The athlete’s medical examination should represent the first aspect of the athlete’s cardiovascular evaluation and should never be forgotten or underestimated. It should always include a proper interview and medical history.
The aim of the cardiovascular examination should be to assess fitness and competence for physical exercise or sports practice as well as to determine the presence of diseases that pose a risk or may be aggravated by sports practice. On the other hand, the examination should always consider the age and type of exercise, as well as the physical and competitive level of the individual, as this will condition the assessment to a large extent.
In 1996, the American Heart Association (AHA) established for the first time the recommendation of a cardiovascular pre-participation study for sports competitions, considering that it is justified from an ethical, legal and medical point of view.
In Europe, the longest experience is that of Italy, which since 1982 has established by law the need for recognition and certification of freedom from cardiovascular disease in order to enter any official sporting competition. Based on the Italian experience, in 2004 the International Olympic Committee (IOC) adopted this strategy in its competitions.
In 2005 the European Society of Cardiology (ESC) made a consensus recommendation on the need for systematic screening of young athletes participating in organised competitions. This screening should start, at the latest, at the age of 12 years and be repeated on a regular basis at least every 2 years. However, there is still great heterogeneity in its implementation, and few countries have implemented it systematically at all levels of competition and not only in elite athletes. These exceptions are Italy, the United States, Israel and Japan.
There are two types of examination: the basic one, which includes a clinical interview, physical examination and echocardiogram, and which is the minimum that every individual should have before taking part in sports competitions; and the complete one, which includes complementary tests such as the stress test and echocardiogram, and which allow a complete assessment of the athlete’s cardiovascular situation.
What can a cardiological examination contribute to my health?
Firstly, through a clinical interview (personal and family history, symptoms with exercise) and physical examination (inspection, auscultation), the presence of certain diseases that pose a risk for sports practice can be ruled out.
Secondly, a resting electrocardiogram is performed. This simple test makes it possible to rule out the presence of potentially dangerous diseases (cardiomyopathies, long QT, heart block).
Thirdly, during the exercise stress test (or ergospirometry), heart rate and blood pressure are monitored. The test can be used to rule out the presence of arrhythmias during exercise or ischaemic heart disease (insufficient irrigation of the heart muscle during exercise).
Finally, echocardiography is a technique that uses ultrasound to visualise the heart in motion. By reproducing its heartbeat, the circulation of blood through the different chambers and blood vessels is observed. It provides information on the shape, size and strength of the heart, the thickness of the walls and the functioning of its valves.
If everything is in order at the cardiac level, this will result in a favourable evaluation and it can be concluded that there are no contraindications for sports practice. If, on the other hand, the presence of any cardiological alteration is detected, the recommendations to be followed regarding physical exercise will be indicated, as well as the need for follow-up and complementary examinations.
The fact that the test runs correctly and no anomaly is detected does not guarantee 100% the possibility of suffering a cardiac event during sports practice. However, the vast majority of cases can be avoided. It should be remembered that the examination is carried out in a cardioprotected environment (clinic) and does not take into account the environmental conditions of sports practice, such as temperature or humidity, lack of rest, or the obstinacy of the athlete to finish a competition even if he/she is not in good condition.
EXERCISE STRESS TEST WITH GAS CONSUMPTION OR ERGOSPIROMETRY
What does the exercise test with gas consumption consist of?
The exercise stress test or ergospirometry is a maximal test, i.e. it lasts until the athlete reaches the maximum possible effort. This does not mean that it has to be prolonged until exhaustion, but rather that we will base it on gasometric criteria that indicate that the maximum effort has been reached and the test can be interrupted.
Ergospirometry provides information on the response of the cardiocirculatory and respiratory systems to exercise.
On the one hand, continuous ECG monitoring during exercise allows us to check the increase in heart rate during the different phases of exercise, as well as to detect abnormal responses such as the appearance of arrhythmias or signs of ischaemia (lack of risk) in the heart. In addition, during the post-exercise recovery phase, it is checked that the return to calm is carried out correctly. This, without forgetting that repeated measurements of blood pressure during exercise allow us to rule out the possibility of an abnormal hypertensive response during exercise that could put the athlete at risk.
On the other hand, the analysis of gas consumption provides us with information on the function of the respiratory apparatus and energy metabolism at a muscular level. To understand it better, we must know what this test allows us to measure.
What should I know about the stress test and its results?
The three main parameters extracted from ergospirometry are the maximum oxygen consumption or VO2max, and the metabolic thresholds. The VT1 or aerobic threshold and the VT2 or anaerobic threshold.
VO2max is a parameter that is genetically determined and provides us with information on the aerobic power of the organism, i.e. the maximum capacity of the organism to capture oxygen from the air, transport it through the blood to the muscles and use it to metabolise carbohydrates and fats. Its values are expressed in ml/kg/min, so in overweight people, it will be lower.
VO2max cannot be improved once the maximum for which an individual is genetically predisposed is reached. If starting from a sedentary lifestyle, VO2max will increase as the athlete improves the level of training until the theoretical maximum value is reached.
VO2max is the most important parameter in exercise physiology as it represents the integrated functioning of all the apparatus and systems (respiratory, circulatory, locomotor) involved in the exercise response. Athletes involved in endurance sports and long duration sports (cycling, long-distance runners, cross-country skiers…) are those who reach the highest values.
The VT1 or aerobic threshold is the parameter that indicates the moment during exercise when carbohydrate metabolism begins in order to obtain energy. Below this threshold, energy metabolism is based on fat consumption. Its development is especially important for endurance sports. It is usually trained at the beginning of the season, during the running-in phase. This requires extensive, continuous training (running, flatland running, etc.) at low heart rates. The optimum is around 65-75% of maximum heart rate.
The VT2 or anaerobic threshold is the highest intensity of effort that an athlete can maintain constantly for a relatively long period of time. It is the highest level of exercise that can be sustained without fatigue. It is therefore the data that best defines the state of fitness of an athlete. To develop it, the competitive athlete can use both intensive continuous training and extensive intervallic training.
Above this threshold, the athlete is no longer able to adequately “clean” from the blood the lactic acid (lactate) that his muscles manufacture to produce energy (all the extra energy he needs and that metabolism with oxygen can no longer provide). Lactate accumulates in the blood, lowering the pH and causing muscle fatigue and exhaustion.
In recreational sport or healthy sport, it is not advisable to train above this threshold, as it generates a haemodynamic and metabolic situation (acidosis, hypotension) that can put your health at risk if you are not properly adapted.
What can the results of ergospirometry contribute to sports practice?
The most important information that can be provided to the athlete is the heart rate at which the different thresholds are reached. With this data, the athlete or their coach, if they have one, can plan their training properly in order to adapt it to specific objectives.
It is important to remember that the information obtained depends on the type of test carried out. The same athlete will not obtain the same VO2max or threshold values if he/she performs the test on a treadmill or on a bicycle. This is because the muscle groups that work in each exercise are not the same. Generally speaking, and taking treadmill running as a reference, the heart rate values obtained for each threshold should be adjusted:
- Rowing: – 5 beats
Cycling: – 10 beats
Swimming: – 15 beats
With the knowledge of the heart rate for each threshold, the 5 training zones can be established.
What is an echocardiogram for?
The data obtained with this examination provide us with more complete information on the state of the vascular and circulatory system, which allows us to detect cardiac alterations that usually go unnoticed in a physical examination or with an electrocardiogram, thus helping to prevent sudden death.
Who should have it done, the echocardiogram?
The echocardiogram is one of the examinations to be performed as part of a complete (not basic) cardiological examination. A complete examination is recommended:
Athletes with suspected heart disease or a family history of sudden death.
Athletes under 35 years of age
Athletes of any age doing high-intensity sport. Such as players at the Soccer Inter-Action High Performance Centre’s football academy.
Athletes who need guidance on the pace of competition or training.
For the first group, an echocardiogram is almost mandatory to exclude heart diseases that can cause sudden death.
For the second and third group, although it is not a mandatory test, it is advisable to have it done at least once in a lifetime. Intense training can cause changes in the heart and sometimes heart problems develop that can only be detected with an echocardiogram. This is why it is a highly recommended test when training and participating in competitions, whether professional or popular. In people over 35 years of age, it can detect structural changes caused by continuous sports practice or diseases such as high blood pressure.
If I have already taken a stress test, isn’t it enough?
If you have already done a stress test with gas consumption, congratulations. You now know how your body responds to physical exercise, at what intensity is your maximum effort, at what intensity of effort you start to accumulate lactate, and what intensity you must maintain in order not to develop fatigue. And above all, that your cardiovascular system is healthy and suitable for exercise. However, you should be aware that your cardiac screening is not complete.
Some heart diseases may not show up in a stress test while they already show changes in the structure of the heart. With the echocardiogram you can be sure that your cardiovascular system has been studied in detail and that there are no current or potential problems in the future.
And if I take all the tests, nothing can happen to me, right?
But remember, the fact that the tests carried out are normal and no abnormality is detected does not guarantee 100% the possibility of suffering a cardiac event during sport. However, it is possible to avoid the vast majority (>95%) of cases, which provides great security.
It is important to remember, once again, that the tests are performed in a cardioprotected environment and cannot replicate the environmental conditions or the specific physical and emotional situation of the athlete on the day of the competition.
And remember, what is really important in sport is not about achieving goals or getting better and better, but about enjoying every day while doing it. Enjoy it safely and stay healthy and happy.
Dr. Josep Lluís Melero Ferrer
Sports Cardiologist at Clinica Jaime I in Catarroja
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- Boraita Pérez A1, Serratosa Fernández L Sudden death in the athlete. The minimal requirements before performing a competitive sport. Rev Esp Cardiol. 1999 Dec;52(12):1139-45.
- Corrado D, Pelliccia A, Bjørnstad HH, et al. Cardiovascular pre-participation screening of young competitive athletes for prevention of sudden death: proposal for a common European protocol. Consensus Statement of the Study Group of Sport Cardiology of the Working Group of Cardiac Rehabilitation and Exercise Physiology and the Working Group of Myocardial and Pericardial Diseases of the European Society of Cardiology. Eur Heart J. 2005 Mar;26(5):516-24.