Academic Editor: Lee Stoner
Cardiovascular disease (CVD) is the most common cause of death globally in general population. Sport activity is an effective and recommended non-pharmacological method of CVD prevention. Presently, the group of people practicing sport regularly is constantly growing due to increasing awareness of its health benefits. However, vigorous-intensity exercises can reveal previously undetected disease. Master athletes over 35 years old are particularly exposed to sudden cardiac death (SCD) mainly in the course of coronary artery disease (CAD). Another common disease in veteran athletes is hypertension. It is known that regular endurance training can lower blood pressure at rest, so arterial hypertension in athletes is usually masked by adaptation to effort. Despite of normal or high-normal blood pressure in the office, the values during exercises and in ambulatory blood pressure monitoring (ABPM) can exceed the norm. Hidden hypertension have the same negative impact on cardiovascular system. It increases the risk of (1) atherosclerosis and therefore myocardial infarction or stroke, (2) left ventricular hypertrophy with diastolic and/or systolic heart failure, myocardial fibrosis and ventricular arrhythmias, (3) left atrial enlargement increasing the risk of atrial fibrillation and stroke and (4) aortic dilation/dissection. Through these complications hypertension can lead to SCD during sport activities, therefore it is important to recognize this disease early and start a proper treatment. To enable safe participation in sports competition detailed guidelines for screening were created, but they mainly concern CAD. We propose an additional scheme of screening in master athletes including the detection of hidden hypertension to prevent its consequences.
Cardiovascular diseases are still leading cause of death globally (WHO), among which ischemic heart disease is the most common. Presently people are more aware of benefits of physical activity. Current WHO guidelines recommend 150–300 minutes of moderate (40–69% peak oxygen uptake—VO2 max, 55–74% maximal heart rate—HR max) or 75–150 minutes of intensive (70–85% VO2 max, 75–90% HR max) aerobic exercises per week [1]. Physically active individuals have lower risk of ischemic cardiovascular disease, stroke and mortality compared to a cohort with a sedentary lifestyle [2]. As a result not only young, but also middle-aged and elderly people want to improve their physical capabilities and participate in competitions. Master (veteran) athletes represent group of athletes in an age category over 35 years, who compete in endurance sports events including for example athletics, swimming, cycling or combination of those. Veteran sports exist from many years and even World Masters Athletics Championship began already in 1975. However, the group of over 35 years old includes a variety of athletes—those who are continuously training since childhood, athletes who want to return to training after a long break, but also a growing number of those who never had contact with competitive sport before. We wanted to highlight the most important issues related to cardiovascular risk in the latter group of veteran athletes, who might have never undergone preparticipation medical screening.
Despite of benefits from regular training, an instant load of huge effort can
result in dangerous adverse events, especially when it concerns insufficiently
trained people who began to participate in competitive sport and may have already
developed acquired cardiovascular diseases such as the amateur veteran athletes.
Many of those individuals had never undergone cardiovascular system assessment
before they start to compete in sports events. It poses them at risk of sudden
cardiac death (SCD) during exercise, which is determined as unexpected death due
to cardiac causes that occur within 1 hour of the onset of symptoms. Risk of SCD
is increased in low-trained athletes and most of incidents happen in individuals
over 35 years old during recreational activity [3, 4]. The cardiovascular
conditions which can lead to SCD are specific for each age group. In young
athletes dominate coronary artery anomalies and arrhythmias mainly due to
congenital diseases. In age
During endurance physical activity cardiac output increases due to the
multiplied stroke volume with an effort up to 30% VO2 max and then due to
constantly increasing heart rate. It is paralleled by rise of the mean arterial
pressure (MAP), but mainly because of increasing systolic blood pressure (SBP). SBP should not exceed 210 mmHg in men or 190 mmHg in women during
maximal exercise and diastolic blood pressure (DBP) should nor rise
Arterial hypertension defined as a blood pressure values
In some cases adaptive response of heart to exercises can mask hypertension.
Hidden hypertension may be suspected if through regular repetitive training
athletes have normal blood pressure in the office and at home, but ABPM reveals
mean 24 hours’ values
Hypertension masked by exercise is more difficult to detect, but has the same consequences (Fig. 1). It increases the risk of cardiovascular events and causes destruction of internal organs such as heart failure and renal dysfunction [27, 28]. Hypertensive response to exercise is also associated with higher risk of cardiovascular events and mortality [29], so it is important to detect hidden hypertension early in order to start right treatment and prevent complications.
Complications of uncontrolled hypertension.
The other common medical condition which can be found in master-athletesis coronary artery disease (CAD) [30], mainly caused by ongoing atherosclerosis. Additionally, chronic coronary syndrome (CCS) is the most common cause of SCD in athletes over 35 years old [5, 7]. This condition requires special attention, because of its asymptomatic course for many years. Gradually progressing occlusion of vessels can lead to critical occlusion or plaque rapture and cause acute coronary syndromes (ACS) with all its consequences. Hypertension is strongly associated with CAD by causing vascular endothelial damage, which induces atherosclerosis [31, 32]. Other risk factors that increase the probability of atherosclerotic plaque progression are age, male gender, non-high-density lipoprotein (non-HDL) cholesterol level, smoking, alcohol, diabetes, obesity and sedentary lifestyle [33]. Management options in CAD prevention and treatment include lifestyle modification, pharmacological treatment, revascularization and proper risk rate and effort selection. Physical activity improves triglycerides level, but only mildly affects low-density lipoprotein (LDL) levels and when necessary treatment with lipid lowering drugs should be initiated [34]. Competitive or intensive efforts can reveal symptoms of angina and result in cardiac ischemia and rhythm disturbances [35].
As previously mentioned, major cause of SCD in athletes over 35 years old is
left ventricular hypertrophy (LVH) [6] with HCM being the main cause, followed by
hypertension. It is also possible that some cases of the so-called idiopathic LVH
may be caused by undiagnosed or masked hypertension. While eccentric hypertrophy
without diastolic impairment is considered to be the result of endurance
exercise, concentric hypertrophy with relaxation disturbances could be an effect
of hidden or already diagnosed but improperly treated hypertension [22, 23].
Athletes with higher blood pressure have not only higher left ventricular
mass/volume ratio and LV wall thickness, but also a lower diastolic function [24, 34]. In some athletes lower left ventricle function can occur at rest, but if it
is a physiological phenomenon it should improve during stress echocardiography by
at least 13% contrary to prolonged systolic dysfunction observed in hypertension
[36]. To differentiate conditions leading to SCD from athlete’s heart,
individuals with LV wall thickening on imaging tests (
Rhythm disturbances are direct cause of death associated with exercise, of which the most dangerous are ventricular arrhythmias. They could be caused by structural heart diseases including HCM, DCM or ACM, adverse myocardial remodeling due to volume overload or increased afterload in hypertension and fibrosis. These findings can be detected during imaging tests. Electrocardiogram can reveal some characteristic features for each cardiomyopathy, but it is essential to confirm it in echocardiography and next in CMR. Suspected cardiomyopathy as well as history of rhythm disturbances is an appropriate reason to perform 24-hour Holter ECG to assess the severity and the type of arrhythmia. Some rhythm disturbances intensify during physical effort, therefore ECG-exercise stress test is necessary to reveal their presence and adequately qualify the patient for the effort load. In individuals with normal cardiac morphology, arrhythmias can be triggered by electrolyte disturbances, to which athletes are particularly exposed during long efforts at high temperature. Additionally, the elderly are characterized by a lower thermoregulation capacity [39]. Therefore adequate hydration and the supply of electrolytes and nutrients during intense exercise are essential, especially in the long endurance competition.
Coronary arteries anomalies and ion channels disorders such as long QT syndrome,
short QT syndrome, Brugada syndrome and catecholaminergic polymorphic ventricular
tachycardia can be recognized in ECG, 24-hour Holter ECG and exercise testing and
are indisputable causes of rhythm disturbances, however, these diagnoses are more
likely at age
More common for athletes are supraventricular arrhythmias. There is a strong correlation between hypertension and atrial fibrillation (AF). High blood pressure not only increases probability of AF occurrence, but these both entities share similar risk factors such as age, male gender, genetic predispositions, inflammatory processes, oxidative stress and obesity [40]. Renin hypertension dominates in the majority of hypertensive patients, what is connected with disturbances in renin-angiotensin-aldosterone system. Increased level of aldosterone can result in arrhythmogenic fibrosis of the left atrium [20, 41]. Furthermore, higher blood pressure as a consequence of endothelial dysfunction due to atherosclerosis increases arterial stiffness and is associated with larger left atrial (LA) diameter [42]. LA overload occurs also because of the impaired left ventricular diastolic function. The atrial size has been shown to be proportionally associated with a stroke risk [43]. Enlargement of the left atrium is a common phenomenon in athlete’s heart, but only if accompanied by improvement of atrial emptying due to improved LV diastolic function [44]. Overall the risk of atrial fibrillation is higher and occurs more often in individuals with higher time and intensity of exercises per week [45]. Because this arrhythmia can lead to hemodynamic disturbances, it should be properly treated. Recommended strategy in athletes with atrial fibrillation is ablation [46, 47]. Beta-blockers are often not used due to reduction of maximum heart rate, what is undesirable in endurance sports. Some rhythm disturbances intensify during physical effort, therefore ECG-exercise stress tests is necessary to reveal their presence and adequately qualify the patient for the effort load.
Hemodynamic load may contribute to subtle enlargement of aorta, which is a normal finding in athlete’s heart especially in endurance sports with high dynamic component [48]. However, when combined with hypertension, it has even greater impact on aorta diameter and increases risk of aorta dilatation, which is also associated with aortic stiffness and may result in adverse cardiovascular events [49, 50]. Ultimately high blood pressure with other risk factors or genetic predispositions can lead to aortic dissection, which is one of the causes of SCD [42]. Aortopathies apply even more to veteran athletes, as the elasticity of arteries decreases with age.
Before participating in competitive sports it is recommended to evaluate the cardiovascular system in order to identify people with symptoms caused by exercise. Thorough medical history with assessment of cardiovascular risk factors followed by physical examination including heart auscultation and blood pressure assessment should always be the first step. Coronary artery disease is characterized by symptoms appearing during increased effort load, so the resting ECG may not detect abnormalities. However, ECG is a good method to reveal signs of left ventricular hypertrophy, left atrial enlargement, arrhythmia or prior myocardial infarction in this group of athletes. ECG exercise test is the most accessible method to assess athletes. It is excellent to reveal arrhythmia and its changes on exercise. Unfortunately, ECG exercise test has low sensitivity in CAD detection (68%) and ST changes during examination are difficult to assess when intraventricular conduction disturbances are present [51, 52]. Therefore, echocardiographic exercise test is recommended to detect CAD and with 85% sensitivity and similar specificity reveal contractility disturbances, which is associated mainly with ischemic effect [53]. As mentioned earlier mildly decreased left ventricular ejection fraction (LVEF) at rest in healthy athletes should also return to normal during exercise test [36, 53]. Despite that, electrocardiographic exercise test is most often used as a first step to evaluate athletes, because this is a fast, easily accessible method, the result is not so operator-dependent as echocardiography. Stress test has limited effectiveness in detecting mild to moderate CAD and single-vessel disease [54]. More sensitive noninvasive method to detect or exclude CAD is an anatomic evaluation with coronary computed tomography angiography (CCTA), which has high negative predictive value [55]. However, hemodynamic significance is showed only by stress tests [56]. The most precise way to assess cardiac structure, function of chambers and myocardial perfusion is CMR. Additionally, CMR stress perfusion has 90% sensitivity and 94% specificity in CAD detection [57]. CMR and CT are not recommended in patients with advanced renal failure, when assessment of myocardial perfusion is possible with single photon emission computed tomography (SPECT) with similar effectiveness. The final invasive method is coronary angiography, during which, if necessary, coronary angioplasty can be performed. Potential red flags found during testing of master athletes, which increase the risk of SCD during sport activity are presented in Fig. 2. Table 1 presents the differentiation of the athlete’s heart from the effects of hypertension and hypertrophic cardiomyopathy using additional tests.
Potential red flags found during testing of master athletes, which increase the risk of SCD during sport activity. ABPM, ambulatory blood pressure monitoring; BP, blood pressure; CMR, cardiac magnetic resonance; CVD, cardiovascular disease; CCTA, coronary computed tomography angiography, LBBB, left bundle branch block; STD, ST-segment depression; TWI, T-wave inversion. CVD risk according to SCORE2 calculator.
Athlete’s heart | HHD | HCM | |
Symptoms (chest pain, dyspnoea, palpitations, presyncope/syncope) | – | + | ++ |
Family history of CVD (hypertension or HCM/SCD) | – | + | + |
ECG changes: | |||
- amplitude criteria of LVH | +/– | + | + |
- signs of LAE | +/– | + | + |
- TWI in infero-lateral leads | – | + | ++ |
- left axis deviation | – | +/– | +/– |
- LBBB | – | +/– | +/– |
Echocardiography: | |||
- mild symmetrical LVH | +/– | + | + |
- asymmetrical LVH | – | – | ++ |
- regression of LVH after detraining or treatment | + | + | – |
- LVOT or intraventricular obstruction | – | +/– | +/– |
- diastolic dysfunction | – | + | + |
- systolic dysfunction | – | +/– | +/– |
- aortic dilatation | – | +/– | – |
- balanced heart chamber enlargement | + | – | – |
CMR: | |||
- patchy LGE other than in junction point | – | +/– | +/– |
Exercise test: | |||
- signs of myocardial ischemia | – | +/– | +/– |
- BP drop during exercise | – | +/– | +/– |
- exaggerated BP response to exercise | – | + | – |
- uncommon ventricular arrhythmia | – | + | ++ |
- lower than predicted physical capacity | – | +/– | +/– |
Holter ECG: | |||
- uncommon ventricular arrhythmia | – | + | ++ |
CVD, cardiovascular disease; HCM, hypertrophic cardiomyopathy; SCD, sudden cardiac death; ECG, electrocardiogram; LAE, left atrial enlargement; TWI, T-wave inversion; LBBB, left bundle branch block; LVH, left ventricular hypertrophy; LVOT, left ventricular outflow tract; CMR, cardiac magnetic resonance; LGE, left gadolinium enhancement; BP, blood pressure. |
Middle-aged male athletes have higher risk of atherosclerotic plaque formation, which is correlated with increasing training intensity. These plaques are mostly calcified, so their composition does not in general pose a high risk of an undesirable cardiovascular events [58]. This explains why endurance athletes live longer despite the calcification of the vessels [59, 60]. For this reason coronary calcium score may have a limited prognostic value in that group and reference values for coronary calcium score in master athletes are lacking.
Any severe rhythm disturbances in resting ECG, during ECG exercise test or symptoms of arrhythmia in medical history require verification in 24-hour Holter ECG. It is also a tool to assess prognosis in cardiomyopathies or after cardiac adverse remodeling and helps to make a proper decision about possible sports restrictions.
In high performance athlete cardiac adaptation to effort must be differentiated from diseases, which require some restrictions in competitive sport and proper treatment. It is important to take activesteps not only in early detection of coronary artery disease in master athletes stressed by current sports cardiology guidelines [19], but also overt and hidden hypertension before its consequences such as coronary artery disease, rhythm disturbances, aortic disorders and cardiac remodeling with fibrosis occur (Fig. 3). Every individual over 35 years old should have assessment of complete lipid profile, blood pressure at rest and subsequently cardiovascular risk estimated using a SCORE2 scale which includes age, gender, blood pressure, smoking nicotine and non-HDL cholesterol to predict probability of fatal and non-fatal cardiovascular events in 10 years in people from four risk regions in Europe. Some additional factors such as diabetes mellitus, familial hypercholesterolemia, highly increased values of total cholesterol, LDL-cholesterol and blood pressure, chronic kidney disease, previous ACS, diagnosed CCS, past stroke, transient ischemic attack and peripheral atherosclerosis impact on the determination of CVD risk directly and divide patients from low risk to very high risk.
The proposed scheme for the detection of hidden-hypertension in athletes aged 36–69. ECG, electrocardiogram; ECHO, echocardiography; CCTA, cardiac computed tomography angiography; ABPM, ambulatory blood pressure monitoring; HFpEF, heart failure with preserved ejection fraction; LGE-CMR, late gadolinium enhancement-cardiac magnetic resonance.
Patients with SCORE2
Hidden hypertension should be suspected in patients who have blood pressure
Despite the important role of screening, an essential method to prevent acquired cardiovascular diseases is prevention. Most of problems related to the cardiovascular system as well as hidden hypertension are caused by unhealthy lifestyle and it usually concerns recreational older athletes more than younger professionals, which have special diets and training plan. Considering that age is also a risk factor of hypertension and CVD due to changes in the structure of arteries [65], master athletes should be especially careful about other factors, as a sedentary lifestyle is only one of them [16, 62]. Strong correlation between dietary total antioxidant capacity and reduced cardiovascular risk should contribute to changes in eating habits not only in people with risk factors, but in all those who want to maintain a healthy lifestyle [66]. Additionally, nonsteroidal anti-inflammatory drugs, which are very often used during sports injuries or some inconsistent with the principles of “fair play” substances, prohibited by World Anti-Doping Agency such as erythropoietin anabolic steroids are characterized by increasing blood pressure [67, 68, 69]. Raising awareness of the risk factors is essential in preventing an increasing number of hypertensive patients.
Sudden cardiac death is very disturbing phenomenon and still appearing during sports competitions, despite of evolving screening methods. On the other side, it is important to cooperate properly with such a specific patient as master athlete and to raise awareness of need for medical examination before performing extreme exercises. The current guidelines in sports cardiology are aimed at revealing CAD, but likewise hidden hypertension may pose a risk of cardiovascular event. The overlapping effects of high blood pressure and athlete’s adaptation to chronic intensive effort, especially mild left ventricular hypertrophy, may cause diagnostic difficulties. Regular physical activity reduces resting blood pressure, what makes hypertension even more difficult to detect, therefore the proposed screening scheme facilitates the search of athletes from high-risk group.
KZ—article conception, design, data collection, manuscript writing. ŁM—article conception, review, editing, supervision and final approval. All authors contributed to editorial changes in the manuscript. All authors read and approved the final manuscript.
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This research received no external funding.
The authors declare no conflict of interest. Łukasz A. Małek is serving as Guest Editor of this journal. We declare that Łukasz A. Małek had no involvement in the peer review of this article and has no access to information regarding its peer review. Full responsibility for the editorial process for this article was delegated to Lee Stoner.