ABSTRACTGILDERS, R. M., C. VONER, and G. A. DUDLEY. Endurance training and blood pressure in normotensive and hypertensive adults.Med. Sci. Sports Exerc., Vol. 21, No. 6, pp. 629–636, 1989. Twenty-one male and female adults 43 ± 4 yr of age completed in 8-wk control period, 16 wk of conditioning, and 12 wk of deconditioning to determine whether exercise alters blood pressure. Subjects were classified as borderline/mild hypertensive (H, diastolic pressure ≥ 85 and < 104 mm Hg,N= 8) or normotensive (N, diastolic pressure < 85 mm Hg,N= 13) based on average blood pressure during the control period. Conditioning increased (P< 0.05) VO2max, to a similar extent in both groups (average, 14%) and decreased (P< 0.05) resting heart rate (H, 78 ± 5 to 65 ± 3; N, 75 ± 3 to 71 ± 3 beats-min-1)-The double product over 24 h of ambulatory monitoring of blood pressure and heart rate decreased (P< 0.05) in both groups. After deconditioning, VO2maxreturned to values not different (P> 0.05) from those of the control period. Ambulatory 24-h double product and heart rate increased (P< 0.05). In spite of this strong evidence of a conditioning effect, neither group showed changes (P> 0.05) in average 24-h ambulatory or casual blood pressure. The average ambulatory blood pressure for 8-h segments of the day (8 a.m.-4 p.m., 4 p.m.-12 a.m., and 12 a.m.-8 a.m.) was also not altered. Cardiac output and total peripheral resistance at rest did not change (P> 0.05). These findings question the generally accepted belief that endurance exercise conditioning reduces blood pressure in hypertensive individuals by decreasing either cardiac output or total peripheral resistance.