EFFECTS OF TRIATHLON TRAINING ON HEMODYNAMIC RESPONSES AND VASCULAR FUNCTION: THE ATHLAS STUDY

Abstract

Objective: Regular and moderate endurance exercise has beneficial effects on the cardiovascular system. Triathlon is a rigorous endurance multisport that requires a higher level of training. Chronic consequences on cardiovascular system of such a high cardiovascular demand have not yet been highlighted. In this study, we assessed the effect of triathlon training and racing on the cardiovascular system in experienced triathletes. Design and method: ATHLAS is a prospective controlled study comparing 34 male recreational long-distance triathletes aged 19 to 39 years (Tri) with 29 healthy insufficiently active of the same age (Ctrl). All volunteers completed three visits throughout an annual sports season: at baseline during the off-season (in winter), at peak of physical performance during races period (in spring/summer), and during active rest in post-season (in autumn). At each visit, peripheral blood pressure was measured, and applanation tonometry was performed to evaluate arterial stiffness by carotid-femoral pulse wave velocity (cfPWV) and myocardial perfusion using the subendocardial viability ratio (SEVR). Results: At baseline, Tri had higher systolic blood pressure (SBP) and pulse pressure (PP) than Ctrl (respectively, 131.1±8.9 vs 125.7±10.4 mmHg; and 56.5±12.8 vs 48.9±6.5 mmHg, p<0.05) but lower cfPWV (6.29 ±0.15 vs 6.95 ±0.16 m/sec, p<0.01). SEVR was increased in Tri indicating better myocardial perfusion (mean difference of 34.42%, p = 0.03). At peak of performance in Tri, SBP and PP were decreased (respectively, mean difference of 3.63 mmHg, and 3.36 mmHg, p<0.05), and returning to baseline levels in active rest. Tri cfPWV and SEVR were not influenced by training phases. In Ctrl group, SBP, PP and cfPWV exhibited seasonal variation with lower levels in spring/summer (p< 0.05). Conclusions: Triathlon training and racing have beneficial effects on arterial stiffness and myocardial perfusion regardless of time of season. In triathletes, increased SBP despite lower arterial stiffness (cfPWV) reflects adaptation of the athlete's heart with a high cardiac output. These results will require further study to determine whether high blood pressure could lead to negative cardiovascular impact in the long term.