DÄ internationalArchive24/2018Exercise Testing in Sports Medicine

Review article

Exercise Testing in Sports Medicine

Dtsch Arztebl Int 2018; 115(24): 409-16; DOI: 10.3238/arztebl.2018.0409

Löllgen, H; Leyk, D

Background: Bicycle and treadmill exercise tests are used in sports medicine and occupational medicine to detect latent disease, to monitor treatment, and to measure patients’ physical performance ability and reserve. In this review, we describe the indications, contraindications, and manner of performance of these tests, along with the variables tested, criteria for evaluation, (sub)maximal stress, and the factors that affect these tests, including age, sex, and medications.

Methods: This review is based on pertinent articles retrieved by a selective literature search and on the ergometry guidelines of four medical specialty societies.

Results: The proper performance of ergometric stress tests calls for preparation and monitoring by qualified staff as well as standardized testing conditions. Ergometric studies are indispensable as a clinical diagnostic method for the early recognition of disease, for follow-up over time, and for individual counseling. The patient’s maximal achievable performance is a predictor of morbidity and mortality. Among the variables that can be measured in the submaximal performance range, the respiratory rate, heart rate, and lactate performance curves are more accurate prognostic predictors than the so-called threshold values (physical working capacity, anaerobic-aerobic threshold). Ergometric stress tests can be used to detect (among other conditions) latent hypertension, pulmonary diseases (e.g., exertional asthma), pabnormal ECG changes, and cardiovascular disorders (e.g., ischemia, arrhythmia, congestive heart failure). The ergometric findings are influenced by the choice of stress-inducing protocol. They provide important information for the planning and monitoring of exercise training and for the treatment of persons suffering from diverse physical conditions, as well as for leisure-time athletes. They are less suitable for use in the design of training programs for high-performance athletes.

Conclusion: Ergometric stress tests provide important data in clinical and preventive medicine. The findings are often difficult to interpret because of the wide range of normal findings, the use of different stress-inducing protocols, and the lack of generally accepted reference values. The establishment of a nationwide fitness and health registry for ergometric data would be very helpful for the individualized interpretation of test findings and for the monitoring of exercise training and therapy.

Ergometric stress testing is indicated to answer relevant questions for athletes, asymptomatic persons, and patients with a wide range of diseases (Box 1). Its most important use is to detect latent disease (health-related indication for testing). It can also be used to measure physical performance ability and reserve and to assess the prognosis of patients with various diseases, as well as to monitor and guide exercise training and the training of athletes. When used in ill patients, it is helpful for evaluating treatment, monitoring interventions, and and assessing the prognosis (1 [p. 51], 2 [p. 60], 3, 4 [p. 268]). Very different groups of persons can benefit from ergometric stress testing, ranging from professional athletes and ambitious leisure-time athletes to untrained persons and ill patients (1 [p. 51], 2 [p. 60], 5, 6, 7 [p. 10]). Further diagnostic objectives are listed in Box 1.

Indications for ergometry in sports medicine*1
Indications for ergometry in sports medicine*1
Box 1
Indications for ergometry in sports medicine*1

The most common standard methods of ergometric testing are bicycle ergometry (in Europe) and treadmill ergometry (in the USA) (1 [p. 21], 2 [p. 162], 4 [p. 238], 8–11). Other testing procedures, such as rowing ergometry, the field step test, rotational ergometry, supine bicycle ergometry, step-climbing, a six-minute walking test, and strength tests are used to measure performance in sport-specific testing and to answer specific clinical questions (4 [p. 238], 12 [p. 519], 13–17). These will not be described in any greater detail in this review.

Method

In this review, we present the indications and contraindications of ergometric stress testing, the manner in which these tests are performed, the variables they measure and their informative value, the criteria for evaluating submaximal and maximal performance, and factors that influence the outcome of the tests (e.g., age, medications, illnesses). This review is based on the current ergometry guidelines of the relevant medical specialty societies (9, 1113, 1820), the literature cited in these guidelines, and a selective literature search in the PubMed/MEDLINE, Cochrane Library, Embase, Scopus, and Web of Science databases (search terms: “ergometry,” “exercise testing,” “functional capacity,” “fitness,” “stress testing”).

Indications

In sports medicine, ergometry is used primarily to measure fitness (“physical capacity”) and endurance, in order to monitor the effects of exercise training in healthy individuals or the effects of treatment (rehabilitation, other measures) in persons with various diseases (Box 1). Further indications include the differential diagnostic evaluation of diseases (heart, lungs) and symptoms, e.g., chest pain or shortness of breath (1 p. 173], 7, 13 [p. 329], 21, 22). The measurement of physical performance for prognostic purposes has become much more common in recent years. Physical fitness (Figure 1) is an indicator of future cardiovascular, metabolic, or even psychiatric events, as well as a means of lowering risk (1 [p. 355, 401], 2, 3, 5, 10, 15, 23, e1–e5). This is true not only for the standard tests (bicycle and treadmill ergometry) but also for grasp strength (e6e9). In a longitudinal study published in 2015, with more than 140 000 participants, grasp strength was a better predictor of morbidity and mortality than systolic blood pressure (e6).

The probability of a serious cardiovascular event as a function of physical fitness (fitness categories based on the maximal performance attained on the ergometric treadmill
The probability of a serious cardiovascular event as a function of physical fitness (fitness categories based on the maximal performance attained on the ergometric treadmill
Figure 1
The probability of a serious cardiovascular event as a function of physical fitness (fitness categories based on the maximal performance attained on the ergometric treadmill

The performance of ergometry

History-taking, physical examination, and rest electrocardiography (ECG) are mandatory prerequisites before the patient is put under any physical stress to detect risks due to latent or overt disease, such as coronary heart disease or hypertension. Standardized conditions must be maintained in the testing room (ambient temperature, humidity, etc.) (eBox 1) (1 [p. 40], 4 [p. 250], 11, 13 [p. 14], 15). Continuous heart rate, blood pressure, and ECG monitoring and observation of the patient are mandatory so that the test can be terminated at once in case any complications arise. The response to emergency situations should be practiced at regular intervals with the nonphysician members of the testing team (eBox 1).

Requirements for ergometric testing*
Requirements for ergometric testing*
eBox 1
Requirements for ergometric testing*

Remarks on testing methods

Bicycle ergometry is used in Europe in preference to treadmill ergometry. Its main advantage is that it less commonly causes artifacts in the stress ECG; treadmill ergometry can also make patients feel insecure or anxious because of the moving surface (4, 7). On the other hand, bicycle ergometry activates a smaller amount of muscle mass than treadmill ergometry and thus generates a maximal performance level that is ca. 10% lower than what is achievable on a treadmill (12 [p. 619], 24 [p. 273]). In supine bicycle ergometry, exhaustion in reached earlier, and the maximal achievable performance is therefore ca. 20% lower.

Standardized stress protocols should be used in order to ensure the validity of inter- and intra-individual comparisons. Different stress protocols are used depending on the category of patient tested and the questions that are to be answered (eTable 1); these protocols vary widely with respect to the initial performance level, the rate increase of performance demanded over time, and the duration of the entire test (1 [p. 47], 9, 25 [p. 155], 26–31). Ramped performance increases and increases in small steps at brief intervals have the advantage of enabling a relatively rapid increase of cardiocirculatory performance. Stress protocols of this type (e.g., an increase by 25 W every 2 minutes, eFigure 1) are suitable, for example, for use in adolescents, or to answer questions of a cardiological nature. The oxygen uptake and the serum lactate concentration respond more slowly to the level of physical performance; thus, measurements of these variables cannot always be reliably attributed to the current performance level (32).

The course of arterial blood pressure during ergometric testing while seated on an exercise bicycle, with performance increments every 2 minutes (mean ± standard deviation) (1, 4)
The course of arterial blood pressure during ergometric testing while seated on an exercise bicycle, with performance increments every 2 minutes (mean ± standard deviation) (1, 4)
eFigure 1
The course of arterial blood pressure during ergometric testing while seated on an exercise bicycle, with performance increments every 2 minutes (mean ± standard deviation) (1, 4)
Recommendations for bicycle ergometric testing protocols*1
Recommendations for bicycle ergometric testing protocols*1
eTable 1
Recommendations for bicycle ergometric testing protocols*1

Performance increases by 40 W or 1.5 km/h every 3 to 5 minutes are often used for the assessment of both the cardiocirculatory and the metabolic component of performance (8, 29, 33) (Figure 2, eFigure 2, eTable 1). If the subject is a high-performance athlete (e.g., a professional cyclist or rower), the test can begin at a higher performance level, e.g., 200–300 W, and maximal performance levels above 500 W are not unusual. At such high performance intensities, blood pressure values of up to 300 mmHg can be regarded as normal (4 [p. 248], 22, 24 [p. 31, 479], 34).

The course of heart rate and lactate concentration in healthy 18- to 35-year-olds undergoing bicycle ergometry (with 4-minute performance steps)
The course of heart rate and lactate concentration in healthy 18- to 35-year-olds undergoing bicycle ergometry (with 4-minute performance steps)
Figure 2
The course of heart rate and lactate concentration in healthy 18- to 35-year-olds undergoing bicycle ergometry (with 4-minute performance steps)
The course of heart rate and lactate concentration in healthy 18- tos 35-year-olds undergoing treadmill ergometry (performance steps of 4 minutes’ duration, with 30-second breaks in between)
The course of heart rate and lactate concentration in healthy 18- tos 35-year-olds undergoing treadmill ergometry (performance steps of 4 minutes’ duration, with 30-second breaks in between)
eFigure 2
The course of heart rate and lactate concentration in healthy 18- tos 35-year-olds undergoing treadmill ergometry (performance steps of 4 minutes’ duration, with 30-second breaks in between)

As soon as the stress test is over, all subjects should be observed for at least a further 6 minutes, as complications such as arrhythmias or a drop in blood pressure tend to occur during this time (4, 20). Staying in motion at a low intensity (0–50 W) helps prevent excessively rapid blood pressure drops (1 [p. 51], 4).

Ergometric stress testing is contraindicated in persons suffering from

  • any acute or severe chronic cardiorespiratory disease causing marked functional impairment (e.g., severe congestive heart failure, high-grade congenital heart defects, cardiomyopathy, severe arrhythmias, thromboses, malignant hypertension, or pulmonary hypertension), or
  • any acute or severe disease of other organ systems, e.g., nephritis, poorly controlled diabetes mellitus, or electrolyte disturbances (1 [p. 51], 11, 26).

The criteria for premature termination of ergometric stress testing (Box 2) are based, among other things, on the experience of the physician conducting the test, as well as on the availability of appropriate emergency measures, such as hemodynamic stabilization, treatment of arrhythmias, cardiopulmonary resuscitation, and defibrillation, in case a severe complication should arise. It follows that ergometric testing in a physician’s outpatient office may be contraindicated for a patient who can, in fact, undergo it in an appropriately equipped testing facility, even in the presence of severe disease, e.g., aortic valvular stenosis. The risk of a life-threatening event or death in a healthy person or athlete undergoing ergometric stress testing has fallen markedly in recent decades to its current level of 0–0.5 cases per 10 000 tests (1 [p. 56], 4 [p. 248], 13). In an older study, 17 fatalities (mainly with supine bicycle testing) and 96 nonfatal complications were reported among 712 285 tested patients with coronary heart disease (e10).

Criteria for the termination of ergometric testing*
Criteria for the termination of ergometric testing*
Box 2
Criteria for the termination of ergometric testing*

Variables measured and the interpretation of findings

The main objective of ergometric stress testing, aside from the diagnostic evaluation of clinical manifestations (dyspnea, dizziness, exhaustion, pain, etc.), is the measurement of parameters relating to exercise physiology for the assessment of stress and performance capacity. The main parameters to be measured and monitored include the performance achieved (in watts or km/h), heart rate (HR), ECG, arterial blood pressure (BP), lactate concentration (Lac), and the spiro-ergometric parameters oxygen uptake (VO2), carbon dioxide release (VCO2), respiratory quotient (RQ = VO2/VCO2), respiratory rate (RR), respiratory minute volume (V̇E), and respiratory equivalent (RE = V̇E/VO2).

The subjective perception of exertion is assessed on the Borg scale (1 [p. 71], 35), ranging from 6 (very, very easy) to 20 (maximal stress). Borg chose this range of values to reflect the heart rate of healthy individuals doing physical work: the Borg score multiplied by 10 can be used to compare the subjective perception of exertion with the heart rate during the work in question. Substantial differences, if present, may reflect the subject’s over- or underestimation of his or her own reserves; they may also be seen, for example, in patients taking beta-blockers. For special questions there are also shorter Borg scales, the so-called CR10 scales (35, e11).

The interpretation of findings: general considerations

The interpretation of the findings requires specialized knowledge and experience, particularly in view of the wide range of normal physiologic values of the measured variables (both within and across individuals). For example, the literature indicates individual ranges of 7–15% for heart rate and arterial blood pressure under stress (22 [p. 161], 36, 37). There are no generally accepted reference values: many studies of highly variable methodological quality are available for each of the measured variables (1 [p. 62], 10, 22 [p. 161], 28, 34).

This variability in the quality of studies is one of the reasons why multiple meta-analyses have not yielded any definitive reference values with corresponding evidence levels (10, 26, 28). Moreover, the results of measurement are heavily influenced by the particular stress-inducing protocol used. For example, the maximal performance attainable in a protocol with stress increments at 2-minute intervals is, understandably, higher than that attainable in an otherwise identical protocol with 3-minute intervals (4 [p. 240], 7, 33). In the submaximal range as well, different settings in different stress protocols (e.g., with respect to HR, VO2, and Lac) can lead to significant differences in the values obtained (4 [p. 270], 32, 33).

Criteria for peak performance

The main criteria for peak performance are the maximal achieved performance, maximal heart rate (HRmax), maximal lactate concentration (Lacmax), maximal oxygen uptake (VO2max), and other spiroergometric parameters (1 [p. 147], 11, 13) (Table). The peak performance criteria are age-dependent and must be set lower for persons over 65 (38). The values given in the Table are reference values that are to be exceeded when the individual achieves peak performance; in other words, only when at least one of the measured values exceeds the corresponding value in the Table can peak performance be said to have been reached. Healthy subjects who have attained one of these reference values can and should stress themselves further up to the point of exhaustion.

Criteria for peak word load—minimal values for adults*1
Criteria for peak word load—minimal values for adults*1
Table
Criteria for peak word load—minimal values for adults*1

The maximal achieved performance is more than just an important indicative value for diagnostic evaluation during exercise training (eTable 2). It is now considered to be a good predictor of the severity of illness and a prognostic criterion for patients with cardiopulmonary disease, and it is used in preventive interventions (Figure 1) (1 [p. 335, 401], 3, 15, 23, 39). In the context of medical evaluations of physical performance, a distinction must be made between maximal performance and performance capacity. The latter is the highest performance that can be achieved without any pathological changes such as ST elevation or cardiac arrhythmia (1 [p. 243], 4 [p. 279]).

Norms for maximal work load (W) with increasing performance level, by age, sex, and body weight (after [e31])
Norms for maximal work load (W) with increasing performance level, by age, sex, and body weight (after [e31])
eTable 2
Norms for maximal work load (W) with increasing performance level, by age, sex, and body weight (after [e31])

Maximal oxygen uptake is considered to be the most important gross spiro-ergometric criterion of peak performance ability. Healthy persons without special training attain VO2max values of 30–45 mL O2/kg/min; world-class rowers, cross-country skiers and marathon runners attain values around 80 mL O2/kg/min. The VO2max can be roughly estimated without direct measurement of gas exchange by way of the maximal achieved performance (e.g., in bicycle ergometry, VO2max = 360 + 11 × performance [W]; in treadmill ergometry, VO2max = 4.25 + 2.98 × speed [km/h]), as the curve of oxygen uptake vs. physical performance is nearly a straight line when the usual ergometric test settings are used (15, 16, 24, e12, e13). The VO2max can also be approximated from the subject’s body weight, HR, and maximal performance with the aid of the classic Astrand rhyming nomogram (2, 24 [p. 273]). Some authors recommend the indirect approximation of oxygen uptake from the heart rate alone, but the values obtained by this method are markedly less reliable than those obtained by direct measurement, because HR values in the maximal range are highly variable (standard deviation ca. 10%) (1, 4, 9, 18, e14).

The maximal heart rate of healthy persons under stress depends mainly on age, rather than the degree of exercise training (28, 33, e15). A further important factor is the mass of working muscle: a higher heart rate can be achieved on a treadmill than on an exercise bicycle. The currently recommended formulae for assessment of the HRmax are, for bicycle ergometry, 208 − 0.7 × age in years (e15) and, for treadmill ergometry, 209.3 − 0.72 × age in years (28). These formulae, based on measured values in large sample groups, are equally valid for men and women.

Interpretation of measured values in the submaximal performance range

The maximal values obtained at peak performance are often the main focus of the diagnostic study, but values that are obtained in the submaximal performance range also have their advantages:

  • The effects of training and therapy can be recognized earlier and more clearly (e16).
  • Motivation plays a smaller role than in peak-performance testing (often a problem in tests done for medicolegal purposes).
  • The risk of a medical event (complication) is lower.
  • Incipient pathological changes already become visible at moderate intensities of stress.

Latent hypertension, for example, can become evident under stress in persons who have a normal blood pressure at rest (e17). On the other hand, an inadequate rise in blood pressure may indicate cardiac dysfunction (e.g., systolic heart failure or arterial hypertension). The response of the heart rate to stress can also reveal pathological changes: a low or slow rise in HR may indicate inadequate chronotropic function (e.g., in coronary heart disease or congestive heart failure), which the clinical history can distinguish from a bradycardic reaction due to training. An excessive rise in HR may be due to lack of training, hyperthyroidism, heart failure, or atrial fibrillation (1 [p. 287], 7, 13 [p. 387]). Pathological ECG changes (e.g., ST elevation or depression, arrhythmias) can arise even at low intensities of stress. Thus, blood pressure measurement and monitoring of the HR and ECG in stress testing in the submaximal performance range are important and, indeed, mandatory safety checks that can reveal ischemia, arrhythmias, and heart failure (2 [p. 130], 9, 11, 13 [p. 351], 23, e18).

Further very important criteria for evaluation in the submaximal performance range are the respiratory rate, heart rate, and lactate concentration curves over time (Figure 2, eFigure 2, eTables 3a, b, eTables 4a, b). In the past, various “threshold” concepts for these values were developed as an aid to the diagnostic evaluation of physical performance and the guidance and monitoring of exercise training (29, 33, e19). For example, the physical working capacity was defined in reference to a given heart rate (PWC 150 = the performance achieved at a heart rate of 150/min, and so forth). This method, however, underestimates performance in persons with a high maximal heart rate and overestimates it in persons with a low maximal heart rate. Moreover, PWC values depend on the subject’s age and sex, among other factors (1 [p. 76], e14, e20, e21). The uncertainties involved in the use of PWC have led to their no longer being used in sports medicine or in clinical medicine (33).

Heart rate values in healthy 18- to 35-year-olds with different levels of maximal work load in bicycle ergometry (achieved maximal performance 160–320 W, 4-minute performance levels, initial level 40 W, increments of 40 W)
Heart rate values in healthy 18- to 35-year-olds with different levels of maximal work load in bicycle ergometry (achieved maximal performance 160–320 W, 4-minute performance levels, initial level 40 W, increments of 40 W)
eTable 3a
Heart rate values in healthy 18- to 35-year-olds with different levels of maximal work load in bicycle ergometry (achieved maximal performance 160–320 W, 4-minute performance levels, initial level 40 W, increments of 40 W)
Heart rate values of healthy 18- to 35-year-olds with different levels of maximal work load in treadmill ergometry (achieved maximal performance 10–19 km/h, 4-minute performance steps, initial speed 8.5 km/h, speed increment 1.5 km/h)
Heart rate values of healthy 18- to 35-year-olds with different levels of maximal work load in treadmill ergometry (achieved maximal performance 10–19 km/h, 4-minute performance steps, initial speed 8.5 km/h, speed increment 1.5 km/h)
eTable 3b
Heart rate values of healthy 18- to 35-year-olds with different levels of maximal work load in treadmill ergometry (achieved maximal performance 10–19 km/h, 4-minute performance steps, initial speed 8.5 km/h, speed increment 1.5 km/h)
Lactate values in healthy 18- to 35-year-olds with different levels of maximal work load in bicycle ergometry (achieved maximal performance 160–320 W, 4-minute performance levels, initial level 40 W, increments of 40 W)
Lactate values in healthy 18- to 35-year-olds with different levels of maximal work load in bicycle ergometry (achieved maximal performance 160–320 W, 4-minute performance levels, initial level 40 W, increments of 40 W)
eTable 4a
Lactate values in healthy 18- to 35-year-olds with different levels of maximal work load in bicycle ergometry (achieved maximal performance 160–320 W, 4-minute performance levels, initial level 40 W, increments of 40 W)
Lactate values values of healthy 18- to 35-year-olds with different levels of maximal work load in treadmill ergometry (achieved maximal performance 10–19 km/h, 4-minute performance steps, initial speed 8.5 km/h, speed increment 1.5 km/h)
Lactate values values of healthy 18- to 35-year-olds with different levels of maximal work load in treadmill ergometry (achieved maximal performance 10–19 km/h, 4-minute performance steps, initial speed 8.5 km/h, speed increment 1.5 km/h)
eTable 4b
Lactate values values of healthy 18- to 35-year-olds with different levels of maximal work load in treadmill ergometry (achieved maximal performance 10–19 km/h, 4-minute performance steps, initial speed 8.5 km/h, speed increment 1.5 km/h)

Rightward and leftward shifts of the lactate-performance curve permit assessment of performance changes and training effects and their monitoring over time (33, e18, e19, e22). Many lactate “threshold” concepts were previously used to detect the highest level of performance (in km/h or watts) at which lactate was still at equilibrium (33) and then derive recommendations for training from this information (1 [S. 213]). It turned out, however, that this transfer was only possible to a limited degree, even in endurance sports (29, 3133).

Interpretation of the post-exercise phase

In the early recovery phase after ergometric stress testing, complications such as arrhythmia and circulatory collapse can arise, and therefore the blood pressure, heart rate, and ECG should still be monitored. The HR response in this phase also provides further diagnostic information: the HR should fall by at least 12 beats/min in the first minute of the recovery period (e23, 22), indicating a good autonomic balance between sympathetic and parasympathetic function (e24). Delayed HR renormalization may indicate disturbed neurohumoral function due to stress, hypertension, lack of training, or other factors (4 [p. 287, 291], e24). On the other hand, slow HR recovery kinetics and high HR in the recovery period are normal if the subject has performed physical work above the limit of sustainable performance (e23).

Factors affecting the ergometrically measured variables

Norms for maximal performance (in watts) are listed in eTable 2 as a function of the main physiological factors affecting them—age, sex, and body weight. The subject’s food intake and physical activity right before testing can also markedly affect performance and lactate values, which depend on glycogen reserves in muscle (1 [p. 216], 13, 24 [p. 31, 71], 32).

Drug intake can also markedly affect ergometric values (eBox 2). Drugs can alter the response to stress, giving rise to either false-positive or false-negative findings on the stress ECG (e.g., ST depression in the absence of disease or lack of ST elevation in the presence of disease). The drug(s) now being taken must therefore be asked about and thoroughly documented, along with the patient’s past medical history and current illnesses, before ergometric testing is performed. Various commonly consumed substances such as nicotine, caffeine, and energy drinks can also affect the ergometric findings, possibly giving rise to tachycardia or an arrhythmia (1 [p. 335], 2 [p. 153], 9, e25).

Medications that can influence ergometric stress testing*
Medications that can influence ergometric stress testing*
eBox 2
Medications that can influence ergometric stress testing*

Overview and future perspective

Ergometry is one of the main forms of preventive testing in sports medicine (5, e26e28). Its prerequisites are a clinical history, a physical examination, and a digital ECG at rest with computer-assisted interpretation. If there are any abnormal findings, ergometric stress testing is the next step in the diagnostic evaluation; cardiac ultrasonography and other tests may also be indicated, but only after stress testing (39, e26, e29). It is a matter of concern that older persons who are just beginning to exercise regularly, as well as persons who only engage in sports in their leisure time, much less commonly undergo sports-related medical evaluations than high-performance athletes do. A survey of over 10 000 long-distance runners revealed that 59.9% of the ambitious athletes, but only 46.8% of the free-time exercisers and 42.0% of the beginning participants, had ever had such a check-up. The corresponding figure for respondents over age 50 was only 40% (1, 5, e26, e29).

Ergometric stress testing yields important information for the planning and monitoring of exercise and treatment. This is true, in particular, with regard to the increasing use of so-called fitness trackers that register fitness– and health-related parameters (e.g., heart rate, distance, speed, sleep duration) through sensors in a bracelet or chest strap. In high-performance sports, the transfer of ergometric laboratory data into detailed training plans is more difficult, as the sport-specific stress pattern is usually very different from the stress protocol used in testing. Further considerations regarding training recommendations can be found on the website of the European Federation of Sports Medicine (www.efsma-scientific.eu).

The creation of a nationwide fitness and health registry would be of great help for the individualized assessment of test findings and of the course of training and treatment effects over time (5, 25, e28). Such a registry would also enable comprehensive statistical and epidemiological studies and would be helpful for the development and evaluation of health initiatives (e28).

Acknowledgement

The authors would like to thank Matthias Krapick (Institute for Preventive Medicine of the German Federal Armed Forces) for his collaboration.

Conflict of interest statement
The authors declare that they have no conflict of interest.

Manuscript submitted on 9 October 2017, revised version accepted on 21 March 2018.

Translated from the original German by Ethan Taub, M.D.

Corresponding author
Prof. Dr. med. Herbert Löllgen
Praxis für Kardiologie und Sportkardiologie
Johannes Gutenberg-Universität Mainz
Bermesgasse 32b
D-42897 Remscheid, Germany

Supplementary material
eReferences:
www.aerzteblatt-international.de/ref2418

eTables, eFigures, eBoxes:
www.aerzteblatt-international.de/18m0409

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Wasserman K, Hansen JE, Sue DY, Stringer W, Whipp BJ: Principles of exercise testing and interpretation: including pathophysiology and clinical applications. Philadelphia: Lippincott Williams & Wilkins 2012.
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Kokkinos PF, Faselis C, Myers J, et al.: Cardiorespiratory fitness and incidence of major adverse cardiovascular events in US Veterans: a cohort study. Mayo Clin Proc 2017; 92: 39–48 CrossRef MEDLINE
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Åstrand PO: Textbook of work physiology. Physiological bases of exercise. 4th ed., Champaign: Human Kinetics 2003.
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Finger JD, Gößwald A, Härtel S, et al.: Messung der kardiorespiratorischen Fitness in der Studie zur Gesundheit Erwachsener in Deutschland (DEGS1). Bundesgesundheitsblatt 2013; 56: 885–93 CrossRef MEDLINE
26.
Lilly LS: Braunwald’s heart disease. Review and assessment. Philadelphia: Elsevier 2016.
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Kaminsky LA, Arena R, Myers J: Reference standards for cardiorespiratory fitness measured with cardiopulmonary exercise testing: data from the fitness registry and the importance of exercise national database. Mayo Clin Proc 2015; 90: 1515–23 CrossRef MEDLINE PubMed Central
28.
Arena R, Myers J, Kaminsky LA: Revisiting age-predicted maximal heart rate: Can it be used as a valid measure of effort? Am Heart J 2016; 173: 49–56 CrossRef MEDLINE PubMed Central
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Leyk D, Baum K, Wamser P, Selle K, Hoffman U, Eßfeld D: Grenzen der Standard-Ausdauerverfahren in den Sportspielen. In: Jeschke D, Lorenz R (eds.): Sportartspezifische Leistungsdiagnostik. Energetische Aspekte, Köln: Sport und Buch Strauß 1998; 243–50.
30.
Baum K, Leyk D, Hoy S: Metabolische und kardiovaskuläre Beanspruchungen bei Badminton, Tennis und Squash im Überblick. Sportorthopädie und Sporttraumatolgie 1997; 13: 1–4.
31.
Leyk D, Schirrmacher L, Hoffmann U, Baum K: Leistungsdiagnostik in den Sportspielen: Kurze Richtungsänderungen Sprints mit Vergleich zwischen Handballspieler, Sprinter, und Ausdauertrainierten. Leistungssport 2000; 30: 31–5.
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Wackerhage H, Leyk D: Muskulärer Energiestoffwechsel und Sport. Köln: Sport und Buch Strauß 2000.
33.
Heck H: Energiestoffwechsel und medizinische Leistungsdiagnostik. Schorndorf: Hofmann 1990.
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Borg G: Borg’s perceived exertion and pain scales. Champaign: Human Kinetics 1998.
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Edvardsen E, Hem E, Anderssen SA: End criteria for reaching maximal oxygen uptake must be strict and adjusted to sex and age. A cross-sectional study. PLoS One 2014; 9: e85276 CrossRef MEDLINE PubMed Central
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Gulati M, Black HR, Shaw LJ, et al.: The prognostic value of a nomogram for exercise capacity in women. J Cardiopulm Rehabil 2005; 25: 386–7 CrossRef
e1.
Liu R, Sui X, Laditka JN, et al.: Cardiorespiratory fitness as a predictor of dementia mortality in men and woman. Med Sci Sports Exerc 2012; 44: 253–9 CrossRef MEDLINE PubMed Central
e2.
Warburton DER, Nicol CW, Bredin SSD: Health benefits of physical activity: the evidence. Can Med Ass J 2006; 174: 801–9 CrossRef MEDLINE PubMed Central
e3.
Myers J, McAuley P, Lavie CJ, Despres JP, Arena R, Kokkinos P: Physical activity and cardiorespiratory fitness as major markers of cardiovascular risk. Their independent and interwoven importance to health status. Prog Cardiovasc Dis 2015; 57: 306–14 CrossRef MEDLINE
e4.
Brill PA, Kohl HW, Blair SN: Anxiety, depression, physical fitness, and all-cause mortality in men. J Psychosom Res 1992; 36: 267–73 CrossRef
e5.
Thomson D, Turner A, Lauder S, et al.: A brief review of exercise, bipolar disorder, and mechanistic pathways. Front Psychol 2015; 6: 147 CrossRef MEDLINE PubMed Central
e6.
Leong DP, Teo KK, Rangarajan S, et al.: Prognostic value of grip strength: findings from the Prospective Urban Rural Epidemiology (PURE) study. The Lancet 2015; 386: 266–73 CrossRef
e7.
Bohannon RW: Hand-grip dynamometry predicts future outcomes in aging adults. J Geriatr Phys Ther 2008; 31: 3–10 CrossRef
e8.
Gale CR, Martyn CN, Cooper C, Sayer AA: Grip strength, body composition, and mortality. Int J Epidemiol 2007; 36: 228–35 CrossRef MEDLINE
e9.
Ortega FB, Silventoinen K, Tynelius P, Rasmussen F: Muscular strength in male adolescents and premature death. Cohort study of one million participants. BMJ 2012; 345: e7279 CrossRef MEDLINE PubMed Central
e10.
Scherer D, Kaltenbach M: Häufigkeit lebensbedrohlicher Komplikationen bei ergometrischen Belastungsuntersuchungen. Dtsch Med Wochenschr 1979; 104: 1161–5 CrossRef MEDLINE
e11.
Borg G: Anstrengungsempfinden und körperliche Aktivität. Dtsch Ärztebl 2004; 101: A1016–21 VOLLTEXT
e12.
Jackson AS, Blair SN, Mahar MT, Wier LT, Ross RM, Stuteville JE: Prediction of functional aerobic capacity without exercise testing. Med Sci Sports Exerc 1990; 22: 863–70 CrossRef
e13.
Artero EG, Jackson AS, Sui X, et al.: Longitudinal algorithms to estimate cardiorespiratory fitness: associations with nonfatal cardiovascular disease and disease-specific mortality. J Am Coll Cardiol 2014; 63: 2289–96 CrossRef MEDLINE PubMed Central
e14.
Ulmer HV, Hufnagel B: Zur Vergleichbarkeit von W170-Testergebnissen in Abhängigkeit von Alter, Geschlecht und Ausdauertrainingszustand. In: Mellerowicz H (ed.): Standardisierung, Kalibrierung und Methodik in der Ergometrie. Ausgewählte Beiträge vom 4. Internationalen Seminar für Ergometrie. Erlangen: Perimed 1981; 122–7.
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e17.
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Private Practice for Cardiology and Sports Cardiology, Johannes Gutenberg University Mainz:
Prof. Dr. med. Herbert Löllgen
Institute of Physiology and Anatomy, German Sport University Cologne;
Bundeswehr Institute for Preventive Medicine, Koblenz:
Prof. Dr. med. Dr. Sportwiss. Dieter Leyk
Indications for ergometry in sports medicine*1
Indications for ergometry in sports medicine*1
Box 1
Indications for ergometry in sports medicine*1
Criteria for the termination of ergometric testing*
Criteria for the termination of ergometric testing*
Box 2
Criteria for the termination of ergometric testing*
The probability of a serious cardiovascular event as a function of physical fitness (fitness categories based on the maximal performance attained on the ergometric treadmill
The probability of a serious cardiovascular event as a function of physical fitness (fitness categories based on the maximal performance attained on the ergometric treadmill
Figure 1
The probability of a serious cardiovascular event as a function of physical fitness (fitness categories based on the maximal performance attained on the ergometric treadmill
The course of heart rate and lactate concentration in healthy 18- to 35-year-olds undergoing bicycle ergometry (with 4-minute performance steps)
The course of heart rate and lactate concentration in healthy 18- to 35-year-olds undergoing bicycle ergometry (with 4-minute performance steps)
Figure 2
The course of heart rate and lactate concentration in healthy 18- to 35-year-olds undergoing bicycle ergometry (with 4-minute performance steps)
Key messages
Criteria for peak word load—minimal values for adults*1
Criteria for peak word load—minimal values for adults*1
Table
Criteria for peak word load—minimal values for adults*1
Requirements for ergometric testing*
Requirements for ergometric testing*
eBox 1
Requirements for ergometric testing*
Medications that can influence ergometric stress testing*
Medications that can influence ergometric stress testing*
eBox 2
Medications that can influence ergometric stress testing*
The course of arterial blood pressure during ergometric testing while seated on an exercise bicycle, with performance increments every 2 minutes (mean ± standard deviation) (1, 4)
The course of arterial blood pressure during ergometric testing while seated on an exercise bicycle, with performance increments every 2 minutes (mean ± standard deviation) (1, 4)
eFigure 1
The course of arterial blood pressure during ergometric testing while seated on an exercise bicycle, with performance increments every 2 minutes (mean ± standard deviation) (1, 4)
The course of heart rate and lactate concentration in healthy 18- tos 35-year-olds undergoing treadmill ergometry (performance steps of 4 minutes’ duration, with 30-second breaks in between)
The course of heart rate and lactate concentration in healthy 18- tos 35-year-olds undergoing treadmill ergometry (performance steps of 4 minutes’ duration, with 30-second breaks in between)
eFigure 2
The course of heart rate and lactate concentration in healthy 18- tos 35-year-olds undergoing treadmill ergometry (performance steps of 4 minutes’ duration, with 30-second breaks in between)
Recommendations for bicycle ergometric testing protocols*1
Recommendations for bicycle ergometric testing protocols*1
eTable 1
Recommendations for bicycle ergometric testing protocols*1
Norms for maximal work load (W) with increasing performance level, by age, sex, and body weight (after [e31])
Norms for maximal work load (W) with increasing performance level, by age, sex, and body weight (after [e31])
eTable 2
Norms for maximal work load (W) with increasing performance level, by age, sex, and body weight (after [e31])
Heart rate values in healthy 18- to 35-year-olds with different levels of maximal work load in bicycle ergometry (achieved maximal performance 160–320 W, 4-minute performance levels, initial level 40 W, increments of 40 W)
Heart rate values in healthy 18- to 35-year-olds with different levels of maximal work load in bicycle ergometry (achieved maximal performance 160–320 W, 4-minute performance levels, initial level 40 W, increments of 40 W)
eTable 3a
Heart rate values in healthy 18- to 35-year-olds with different levels of maximal work load in bicycle ergometry (achieved maximal performance 160–320 W, 4-minute performance levels, initial level 40 W, increments of 40 W)
Heart rate values of healthy 18- to 35-year-olds with different levels of maximal work load in treadmill ergometry (achieved maximal performance 10–19 km/h, 4-minute performance steps, initial speed 8.5 km/h, speed increment 1.5 km/h)
Heart rate values of healthy 18- to 35-year-olds with different levels of maximal work load in treadmill ergometry (achieved maximal performance 10–19 km/h, 4-minute performance steps, initial speed 8.5 km/h, speed increment 1.5 km/h)
eTable 3b
Heart rate values of healthy 18- to 35-year-olds with different levels of maximal work load in treadmill ergometry (achieved maximal performance 10–19 km/h, 4-minute performance steps, initial speed 8.5 km/h, speed increment 1.5 km/h)
Lactate values in healthy 18- to 35-year-olds with different levels of maximal work load in bicycle ergometry (achieved maximal performance 160–320 W, 4-minute performance levels, initial level 40 W, increments of 40 W)
Lactate values in healthy 18- to 35-year-olds with different levels of maximal work load in bicycle ergometry (achieved maximal performance 160–320 W, 4-minute performance levels, initial level 40 W, increments of 40 W)
eTable 4a
Lactate values in healthy 18- to 35-year-olds with different levels of maximal work load in bicycle ergometry (achieved maximal performance 160–320 W, 4-minute performance levels, initial level 40 W, increments of 40 W)
Lactate values values of healthy 18- to 35-year-olds with different levels of maximal work load in treadmill ergometry (achieved maximal performance 10–19 km/h, 4-minute performance steps, initial speed 8.5 km/h, speed increment 1.5 km/h)
Lactate values values of healthy 18- to 35-year-olds with different levels of maximal work load in treadmill ergometry (achieved maximal performance 10–19 km/h, 4-minute performance steps, initial speed 8.5 km/h, speed increment 1.5 km/h)
eTable 4b
Lactate values values of healthy 18- to 35-year-olds with different levels of maximal work load in treadmill ergometry (achieved maximal performance 10–19 km/h, 4-minute performance steps, initial speed 8.5 km/h, speed increment 1.5 km/h)
1. Löllgen H, Erdmann E, Gitt AK (eds.): Ergometrie. Belastungsuntersuchungen in Klinik und Praxis. Berlin, Heidelberg: Springer 2010.
2. Pescatello LS (ed.): ACSM‘s guidelines for exercise testing and prescription. Baltimore: Lippincott Williams & Wilkins 2014.
3. Ross R, Blair SN, Arena R, et al.: Importance of assessing cardiorespiratory fitness in clinical practice. A case for fitness as a clinical vital sign: a scientific statement from the American Heart Association. Circulation 2016; 134: e653-99 CrossRef MEDLINE
4. Löllgen H: Kardiopulmonale Funktionsdiagnostik. Nürnberg: Novartis Pharma 2005.
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6. Löllgen H, Leyk D, Löllgen D: Verordnen Sie Bewegung auf Rezept! Evidenzbasierte Empfehlungen für die Trainingsberatung im Breitensport. MMW-Fortschritte der Medizin 2011; 153: 29–32 CrossRef
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18. Deutsche Gesellschaft für Kardiologie – Herz- und Kreislaufforschung (DGK): Leitlinien zur Ergometrie. Z Kardiol 2000; 89: 136–43 CrossRef CrossRef
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20. Wonisch M, Berent R, Klicpera M, et al.: Praxisleitlinien Ergometrie. Austr J Cardiolog 2008; 15: 3–17.
21. Löllgen H: Bedeutung und Evidenz der körperlichen Aktivität zur Prävention und Therapie von Erkrankungen. Dtsch Med Wochenschr 2013; 138: 2253–9 CrossRef MEDLINE
22. Wasserman K, Hansen JE, Sue DY, Stringer W, Whipp BJ: Principles of exercise testing and interpretation: including pathophysiology and clinical applications. Philadelphia: Lippincott Williams & Wilkins 2012.
23. Kokkinos PF, Faselis C, Myers J, et al.: Cardiorespiratory fitness and incidence of major adverse cardiovascular events in US Veterans: a cohort study. Mayo Clin Proc 2017; 92: 39–48 CrossRef MEDLINE
24. Åstrand PO: Textbook of work physiology. Physiological bases of exercise. 4th ed., Champaign: Human Kinetics 2003.
25. Finger JD, Gößwald A, Härtel S, et al.: Messung der kardiorespiratorischen Fitness in der Studie zur Gesundheit Erwachsener in Deutschland (DEGS1). Bundesgesundheitsblatt 2013; 56: 885–93 CrossRef MEDLINE
26. Lilly LS: Braunwald’s heart disease. Review and assessment. Philadelphia: Elsevier 2016.
27. Kaminsky LA, Arena R, Myers J: Reference standards for cardiorespiratory fitness measured with cardiopulmonary exercise testing: data from the fitness registry and the importance of exercise national database. Mayo Clin Proc 2015; 90: 1515–23 CrossRef MEDLINE PubMed Central
28. Arena R, Myers J, Kaminsky LA: Revisiting age-predicted maximal heart rate: Can it be used as a valid measure of effort? Am Heart J 2016; 173: 49–56 CrossRef MEDLINE PubMed Central
29. Leyk D, Baum K, Wamser P, Selle K, Hoffman U, Eßfeld D: Grenzen der Standard-Ausdauerverfahren in den Sportspielen. In: Jeschke D, Lorenz R (eds.): Sportartspezifische Leistungsdiagnostik. Energetische Aspekte, Köln: Sport und Buch Strauß 1998; 243–50.
30. Baum K, Leyk D, Hoy S: Metabolische und kardiovaskuläre Beanspruchungen bei Badminton, Tennis und Squash im Überblick. Sportorthopädie und Sporttraumatolgie 1997; 13: 1–4.
31.Leyk D, Schirrmacher L, Hoffmann U, Baum K: Leistungsdiagnostik in den Sportspielen: Kurze Richtungsänderungen Sprints mit Vergleich zwischen Handballspieler, Sprinter, und Ausdauertrainierten. Leistungssport 2000; 30: 31–5.
32.Wackerhage H, Leyk D: Muskulärer Energiestoffwechsel und Sport. Köln: Sport und Buch Strauß 2000.
33. Heck H: Energiestoffwechsel und medizinische Leistungsdiagnostik. Schorndorf: Hofmann 1990.
34. Wilson MG, Drezner J, Sharma S: IOC manual of sports cardiology. Chichester: Wiley Blackwell 2017.
35. Borg G: Borg’s perceived exertion and pain scales. Champaign: Human Kinetics 1998.
36.Löllgen H, Haninger B, Just H: Langzeitvariabilität ergometrischer Messgrößen. In: Kindermann W, Hort W (eds.): Sportmedizin für Breiten- und Leistungssport: Berichtsband Deutscher Sportärztekongreß Saarbrücken 16.10.–19.10.1980. Gräfelfing: Demeter-Verlag 1980, S. 73–8.
37. von Nieding G, Krekeler H, Löllgen H, Ripplinger E: Intraindividuelle Variabilität von Lungenfunktionsgrößen im Längsschnitt und ihre Bedeutung für die arbeitsmedizinische Untersuchung. Prax Klin Pneumol 1977; 31: 858–71 MEDLINE
38.Edvardsen E, Hem E, Anderssen SA: End criteria for reaching maximal oxygen uptake must be strict and adjusted to sex and age. A cross-sectional study. PLoS One 2014; 9: e85276 CrossRef MEDLINE PubMed Central
39. Gulati M, Black HR, Shaw LJ, et al.: The prognostic value of a nomogram for exercise capacity in women. J Cardiopulm Rehabil 2005; 25: 386–7 CrossRef
e1.Liu R, Sui X, Laditka JN, et al.: Cardiorespiratory fitness as a predictor of dementia mortality in men and woman. Med Sci Sports Exerc 2012; 44: 253–9 CrossRef MEDLINE PubMed Central
e2. Warburton DER, Nicol CW, Bredin SSD: Health benefits of physical activity: the evidence. Can Med Ass J 2006; 174: 801–9 CrossRef MEDLINE PubMed Central
e3.Myers J, McAuley P, Lavie CJ, Despres JP, Arena R, Kokkinos P: Physical activity and cardiorespiratory fitness as major markers of cardiovascular risk. Their independent and interwoven importance to health status. Prog Cardiovasc Dis 2015; 57: 306–14 CrossRef MEDLINE
e4. Brill PA, Kohl HW, Blair SN: Anxiety, depression, physical fitness, and all-cause mortality in men. J Psychosom Res 1992; 36: 267–73 CrossRef
e5. Thomson D, Turner A, Lauder S, et al.: A brief review of exercise, bipolar disorder, and mechanistic pathways. Front Psychol 2015; 6: 147 CrossRef MEDLINE PubMed Central
e6. Leong DP, Teo KK, Rangarajan S, et al.: Prognostic value of grip strength: findings from the Prospective Urban Rural Epidemiology (PURE) study. The Lancet 2015; 386: 266–73 CrossRef
e7. Bohannon RW: Hand-grip dynamometry predicts future outcomes in aging adults. J Geriatr Phys Ther 2008; 31: 3–10 CrossRef
e8. Gale CR, Martyn CN, Cooper C, Sayer AA: Grip strength, body composition, and mortality. Int J Epidemiol 2007; 36: 228–35 CrossRef MEDLINE
e9. Ortega FB, Silventoinen K, Tynelius P, Rasmussen F: Muscular strength in male adolescents and premature death. Cohort study of one million participants. BMJ 2012; 345: e7279 CrossRef MEDLINE PubMed Central
e10. Scherer D, Kaltenbach M: Häufigkeit lebensbedrohlicher Komplikationen bei ergometrischen Belastungsuntersuchungen. Dtsch Med Wochenschr 1979; 104: 1161–5 CrossRef MEDLINE
e11. Borg G: Anstrengungsempfinden und körperliche Aktivität. Dtsch Ärztebl 2004; 101: A1016–21 VOLLTEXT
e12. Jackson AS, Blair SN, Mahar MT, Wier LT, Ross RM, Stuteville JE: Prediction of functional aerobic capacity without exercise testing. Med Sci Sports Exerc 1990; 22: 863–70 CrossRef
e13. Artero EG, Jackson AS, Sui X, et al.: Longitudinal algorithms to estimate cardiorespiratory fitness: associations with nonfatal cardiovascular disease and disease-specific mortality. J Am Coll Cardiol 2014; 63: 2289–96 CrossRef MEDLINE PubMed Central
e14.Ulmer HV, Hufnagel B: Zur Vergleichbarkeit von W170-Testergebnissen in Abhängigkeit von Alter, Geschlecht und Ausdauertrainingszustand. In: Mellerowicz H (ed.): Standardisierung, Kalibrierung und Methodik in der Ergometrie. Ausgewählte Beiträge vom 4. Internationalen Seminar für Ergometrie. Erlangen: Perimed 1981; 122–7.
e15.Tanaka H, Monahan KD, Seals DR: Age-predicted maximal heart rate revisited. J Am Coll Cardiol 2001; 37: 153–6 CrossRef
e16.Lannoy L de, Sui X, Lavie CJ, Blair SN, Ross R: Change in submaximal cardiorespiratory fitness and all-cause mortality. Mayo Clin Proc 2018; 93: 184–90 CrossRef MEDLINE
e17. Schultz MG, Otahal P, Cleland VJ, Blizzard L, Marwick TH, Sharman JE: Exercise-induced hypertension, cardiovascular events, and mortality in patients undergoing exercise stress testing: a systematic review and meta-analysis. Am J Hypertens 2013; 26: 357–66 CrossRef MEDLINE
e18.Hollmann W, Strüder HK, Predel HG, Tagarakis CVM: Spiroergometrie. Kardiopulmonale Leistungsdiagnostik des Gesunden und Kranken. Stuttgart: Schattauer 2006.
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