Hypertension in Special Populations: Athletes

Rosa Maria Bruno; Giulia Cartoni; Stefano Taddei

Disclosures

Future Cardiol. 2011;7(4):571-584. 

In This Article

Abstract and Introduction

Abstract

Physical exercise is known to lower blood pressure and reduce cardiovascular risk through a wide range of mechanisms. Nevertheless, hypertension is the most prevalent cardiovascular disease among athletes and physically active subjects. This article reviews the state of the art in practical approaches to this issue, focusing on special aspects a physician should take into account when diagnosing hypertension, such as screening of secondary causes, assessment of global cardiovascular risk and target organ damage and, in addition, the treatment choice in athletes.

Introduction

Arterial hypertension, although becoming increasingly more frequent with aging, is the most prevalent cardiovascular risk factor in each age-class. Its prevalence is about 29% in the US population aged >18 years.[1] A linear relationship has been demonstrated for each age-class between systolic and diastolic blood pressure values and cardiovascular morbidity and mortality, as well as heart failure, peripheral artery disease and end-stage renal disease.[2] For these reasons, arterial hypertension represents the leading cause of death in the world according to the WHO.[3] Given the linearity of the relationship between blood pressure values and cardiovascular risk, with no evidence of threshold up to 115/75 mmHg, any classification and definition of hypertension appears to be arbitrary. Nevertheless, for practical reasons, in order to make diagnosis and treatment easier, a conventional classification is used: in particular, arterial hypertension is defined by systolic and/or diastolic blood pressure values equal to or greater than 140/90 mmHg.[4] As illustrated in Table 1, arterial hypertension can be classified according to severity of blood pressure values; interestingly, an intermediate category, named high-normal blood pressure, is defined: although it was suggested that people with high-normal blood pressure and high cardiovascular risk could be considered and treated as hypertensive patients,[4] the most recent reappraisal of European guidelines recommend more caution and discourages the use of aggressive approaches.[5] It is also important to notice that this classification refers to office blood pressure, that means blood pressure measured in a clinical setting by a physician or a nurse, while home and 24-h blood pressure reference values are lower.[4]

Athletes are usually young individuals appearing to be in good health, who perform systematic physical exercise at high intensity. Accordingly, this is a population at low cardiovascular risk. The number of athletes who die of cardiovascular or related causes each year in the USA is probably less than 300, compared with the large number of athletes participating in a broad spectrum of organized sports (about 10 to 15 million) of all ages in the USA.[6] The incidence of sudden cardiac death in young competitive athletes (<40 years) in the USA is even lower, approximately 66 per year.[7,8] Despite their rarity, such deaths are highly emotional events, since they frequently occur while the subject is engaged in athletic activity and involve young and otherwise healthy individuals. The main causes of cardiovascular death are congenital or idiopathic diseases, including hypertrophic cardiomyopathy (36%) and congenital coronary artery abnormalities, as well as traumatic events.[7,8] Hypertension itself is not associated with an increased risk of sudden cardiac death. However, coronary heart disease has been identified in the great majority of exercise-related sudden deaths above the age of 40.[9] Moreover, the various different sports do not provide equal cardiovascular protection. A survey conducted in 2049 Finnish elite male athletes demonstrated that former athletes who had performed endurance or mixed sports during youth had a lower rate of hospitalization for ischemic heart disease as compared with controls, while power sports athletes (boxing, wrestling, weight lifting) were at an even greater risk than sedentary subjects.[10] In this complex scenario, the issue of hypertension in athletes should not be disregarded, for several reasons. First, although prevalence of hypertension in athletes is still an unresolved issue, it is reasonable to estimate that it is approximately 50% lower among sports practitioners than in the general population.[11] Thus, arterial hypertension is the most prevalent cardiovascular condition even in athletes.[12] Furthermore, increased life expectancy and quality, and growing attention to fitness and lifestyle measures to counteract cardiovascular disease in Western countries, is leading to a non-negligible number of physically active aged subjects, in whom classical cardiovascular risk factors are expected to be well represented. Thus, specialists in hypertension and sports medicine are very likely to encounter such patients in their everyday activity, with two main roles:

  • To apply the classical principles of cardiovascular prevention to this subset of population. Indeed, almost all sudden cardiac deaths above the age of 40 years occurred in subjects presenting cardiovascular risk factors,[9] thus it is likely that these deaths would have been prevented with standard treatment.

  • To diagnose and treat hypertension and, more generally, assess global cardiovascular risk, which is mandatory for a decision on sports eligibility.

It is also important to consider that hypertension per se can limit exercise performance: untreated hypertension can decrease exercise capacity, by means of impairment of left ventricular diastolic filling, regardless the presence of left ventricular hypertrophy or diastolic/systolic dysfunction at rest;[13–15] furthermore some antihypertensive medications can impair cardiovascular adaptation to exercise. This article aims to clarify, in a user-friendly style, the key concepts involving pathophysiological aspects, specific features in diagnostic evaluation, criteria for sport eligibility, effect of performance-enhancing drugs on the cardiovascular system, target organ damage assessment and therapeutic choices.

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