Key result
Aerobic exercise at 40% and 60% VO2max reduced systolic blood pressure by 6 mm Hg compared to non-exercise control over 10 hours in men with low dietary calcium intake, but not in those with high intake.
Why the study?
Does acute aerobic exercise reduce blood pressure in men with elevated blood pressure, and is this response modulated by dietary calcium intake and RAS polymorphisms?
RCT (n=50)
Single-blind
Random order crossover
No
Does acute aerobic exercise reduce blood pressure in men with elevated blood pressure, and is this response modulated by dietary calcium intake and RAS polymorphisms?
Postexercise hypotension is more pronounced in hypertensive men with low dietary calcium intake, and this response is further modulated by ACE I/D and AT1R A/C polymorphisms.
May warrant dietary calcium assessment before exercise for BP control; extends evidence on intake-dependent postexercise hypotension.
BACKGROUND: Dietary calcium intake and the renin angiotensin system (RAS) regulate blood pressure (BP) by modulating calcium homeostasis. Despite similar BP regulatory effects, the influence of dietary calcium intake alone and combined with RAS polymorphisms on the BP response following acute aerobic exercise (i.e., postexercise hypotension) has not been studied. Thus, we examined the effect of dietary calcium intake and selected RAS polymorphisms on postexercise hypotension. METHODS: Subjects were men (n = 50, 43.8 +/- 1.3 yr) with high BP (145.3 +/- 1.5/85.9 +/- 1.1 mm Hg). They completed three experiments: non-exercise control and two cycle bouts at 40% and 60% of maximal oxygen consumption (VO2max). Subjects provided 3 d food records on five protocol-specific occasions. Dietary calcium intake was averaged and categorized as low (<880 mg/d = LowCa) or high (> or = 880 mg/d = HighCa). RAS polymorphisms (angiotensin converting enzyme insertion/deletion, ACE I/D; angiotensin II type 1 receptor, AT1R A/C) were analyzed with molecular methods. Genotypes were reduced from three to two: ACE II/ID and ACE DD; or AT1R AA and AT1R CC/AC. Repeated measure ANCOVA tested if BP differed among experiments, dietary calcium intake level and RAS polymorphisms. RESULTS: Systolic BP (SBP) decreased 6 mm Hg after 40% and 60% VO2max compared to non-exercise control for 10 h with LowCa (p < 0.01), but not with HighCa (p > or = 0.05). Under these conditions, diastolic BP (DBP) did not differ between dietary calcium intake levels (p > or = 0.05). With LowCa, SBP decreased after 60% VO2max versus non-exercise control for 10 h among ACE II/ID (6 mm Hg) and AT1R AA (8 mm Hg); and by 8 mm Hg after 40% VO2max among ACE DD and AT1R CC/CA (p < 0.01). With HighCa, SBP (8 mm Hg) and DBP (4 mm Hg) decreased after 60% VO2max compared to non-exercise control for 10 h (p < 0.05), but not after 40% VO2max (p > or = 0.05). CONCLUSION: SBP decreased after exercise compared to non-exercise control among men with low but not high dietary calcium intake. Dietary calcium intake interacted with the ACE I/D and AT1R A/C polymorphisms to further modulate postexercise hypotension. Interactions among dietary calcium intake, exercise intensity and RAS polymorphisms account for some of the variability in the BP response to exercise.
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Pescatello et al. (2007) conducted an RCT in High normal to Stage 1 hypertension (n=50). Aerobic exercise (40% and 60% VO2max) vs. Non-exercise control (seated rest) was evaluated on Systolic blood pressure (SBP) change over 10 hours (-6 mm Hg, p=<0.01). Aerobic exercise at 40% and 60% VO2max reduced systolic blood pressure by 6 mm Hg compared to non-exercise control over 10 hours in men with low dietary calcium intake, but not in those with high intake.
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