Discussion
Cardiovascular evaluation of highly trained athletes and physically active individuals usually comprises the exercise testing not only to exclude underlying pathologic conditions, but more commonly to assess their physical performance. In this context, knowledge of the normal BP response to exercise is a key component of the medical evaluation.19,20 At present, however, conflicting opinions regarding the clinical value and scarcity of information of the normal response to exercise have often blunted the utility of recording exercise BP values.7–9,11,21–27 Our investigation was planned to fill this cultural gap, by providing the referral values for BP response to exercise, to be implemented in the CV evaluation of healthy and physically active individuals undergoing exercise testing. The major findings of our study are as follows: (1) at maximum exercise, the systolic BP substantially increases from the baseline values, whereas the diastolic BP shows only minimal changes; (2) the reference values for maximal systolic BP (calculated as 95th percentile) are 220 mm Hg in male and 200 mm Hg in female athletes (for diastolic BP 85 and 80 mm Hg, respectively); and (3) a small subset of our athlete's population (7.5%) exceeds these limits, without presenting clinical correlates suggestive for hypertension or any pathologic condition. As expected, the physiologic response of CV system to exercise in athletes is characterized by an increase in heart rate and systolic BP (Figure 1), in response to the increased sympathetic drive, and associated to increased cardiac output.6,28–30 In our athlete's cohort, likely due to extensive peripheral vasodilation, the diastolic BP remains usually unchanged even at maximum exercise.6,28 The maximum systolic BPs we identified as threshold values (220 in male and 200 in female) are relatively higher than those reported by ESC (b210 mm Hg for men and b190 mm Hg for women) and ACC/AHA guidelines (b214 mm Hg); as an example, if the established ESC reference values were used in our population, a remarkably large number of healthy athletes (12% male and 21% female) would have been (mis)classified as abnormal BP responders.4,12 Several factors may be advocated to explain this discrepancy, including the young age of our population, the homogenous Caucasian origin, and the type of exercise (bicycle). Moreover, a relevant reason for the higher threshold values we observed is the uniqueness of our population, comprising young healthy individuals who have been training at very high level for a long period of their life and were able to achieve astonishing performances.
