Bright light increases blood pressure and rate-pressure product after a single session of aerobic exercise in men.

This study aimed to test whether bright light (BL) exposure attenuates the reduction in blood pressure (BP) postexercise compared to dim light (DL). Twenty healthy men (27 ± 5 years) randomly underwent two experimental sessions: one under BL (5000 lux) and another under dim light (DL <8lux). In each session, subjects executed a bout of aerobic exercise (cycle ergometer, 30 min, moderate intensity). BP (oscillometric) and heart rate (HR monitor) were measured, and rate-pressure-product (RPP) was calculated. Additionally, a 24-h ambulatory blood pressure monitoring (ABPM) was conducted after the sessions. Systolic BP decreased while HR increased significantly and similarly after the exercise in both sessions. Additionally, systolic BP levels were higher in BL than DL throughout the experimental session (P = 0.04). Diastolic (P = 0.02) and mean (P = 0.03) BPs decreased after exercise in DL (at 30 min), and increased in BL (at 60 and 90 min). RPP increased in both sessions postexercise, but with a main effect revealing higher levels throughout the experimental session in BL than DL (P = 0.04) and during the first 3 h of ABPM (p = 0.05). In healthy men, BL exposure increased systolic BP and cardiac work, and abolished the postexercise decreases of diastolic and mean BPs.