Ergometry is the process of creating a performance profile for a patient’s cardiovascular system. Ergometry thus takes place as part of aptitude tests and sports medicine examinations or to prognosticate cardiopulmonary conditions. Contraindications to exercise testing include acute myocardial infarction, severe cardiac insufficiency, or excessive resting blood pressure values.
What is ergometry?
Ergometry is a performance profile for a patient’s cardiovascular system. Ergometry measures performance parameters of the cardiovascular system under targeted stress to the organism. Literally translated, the ancient Greek term means “work measurement”. In most cases, ergometric tests correspond to graded stress tests. The purpose is to objectively assess a patient’s physical performance. The conditions of each ergometric test are exactly reproducible. This means that ergometric tests can be specifically repeated and compared with each other. The measuring device of an ergometry is also called an ergometer and records extensive data of the cardiovascular system. Precursors of ergometers already existed towards the end of the 18th century. In Germany, the first ergometers are built in the 19th century. The physician C. Speck becomes a pioneer in this field. Both bicycle and running ergometers are produced between the 19th and 20th centuries. Today there are also rowing ergometers, swimming channel ergometers or paddle ergometers. In addition to step tests, performance measurement is now also performed as endurance tests. Documentation of cross-sectional as well as longitudinal tests is possible with modern ergometers.
Function, effect and goals
Mostly, ergometry takes place in the context of sports or occupational medicine. The procedure serves diagnostic or prognostic purposes in particular. Especially in the assessment of heart and lung diseases, ergometric tests take place in the medical field. As part of an aptitude test, ergometry is also often used to diagnose the performance of athletes or patients from certain professions. Examples of such professions are the fire department, the police or NASA. The ergometer can be used to precisely record a patient’s performance level. For athletes, for example, ergometric tests are often used to create a training plan that is precisely tailored to their personal performance level. In rehabilitation facilities, ergometers are also often used as training equipment. Because of the reproducibility of ergometric conditions, patients’ performance can be recorded over a period of time and reliably compared with baseline values. In this way, rehabilitation successes can be documented and analyzed in a meaningful way. Under certain circumstances, the ergometer can also be used as a documentation tool for disease progression. The exact procedure of an ergometry differs with the field of application and the ergometer. In the case of performance diagnostics, the respective work associations or sports federations usually determine the scope of the test. Standard ergometry ends after completion of the specified steps. Step ergometry, on the other hand, increases at predetermined intervals until the patient can do no more. On a bicycle ergometer, for example, the power can be increased by 50 watts every three minutes. On a treadmill, on the other hand, the treadmill speed is increased by 0.5 m/s at predefined intervals. During this targeted exercise, the patient’s blood pressure is measured. In medical diagnostic ergometry, an additional device for logging lung function is usually connected to the ergometer. An example of such a device is the ergospirometer. In the medical field, ergometry usually corresponds to a step test performed according to WHO criteria. The stress period is between nine and twelve minutes. After a resting ECG, the test is normally started with a load of 25 or 40 watts. After every two minutes, the physician increases the load by 25 watts, for example. The maximum pulse rate to be achieved is calculated using the formula 220 minus the patient’s age. The Bruce protocol usually serves as the standard protocol when performed on a treadmill. In cardiac patients, ergometry allows prognostic conclusions about life expectancy. The risks of surgery can also be determined in this way.Finally, the performance of a patient is usually given as an absolute value, but also relative to the target performance.
Risks, side effects, and hazards
For the patient, ergometry is associated with risks. Fatal adverse events rarely occur. Medical science estimates the prevalence of fatal consequences to be between one in 50,000 and one in 600,000. Despite the low fatality rate, ventricular fibrillation sometimes occurs during ergometry, especially in cardiac patients. This scenario may require the use of a defibrillator. In some cases, patients also suffer circulatory collapse during exercise. Despite these possible risks, medicine speaks of a relatively safe method. Serious incidents during stress tests are therefore comparatively rare. Nevertheless, the contraindications to ergometry must be carefully considered in advance. Unstable angina pectoris prohibits exercise testing, as does acute myocardial infarction. Aortic aneurysms, severe valvular heart disease and carditis as well as severe hypertension or heart failure are also considered contraindications. If the patient’s regular blood pressure is above 200/120 mmHg or if heart muscle inflammation is present, ergometry should also not be used. Patients may need to discontinue certain medications prior to ergometry. Unlike for many other diagnostic tests, the patient should not appear fasting for ergometry, but should at least have eaten breakfast. Side effects of ergometry sometimes include muscle soreness-like symptoms the following day. Pain in the joints can also occur. The same is true for temporary shortness of breath.
