ObjectiveTo investigate the effect on blood pressure for 10-min compared with 40-min episodes of physical activity for 4 days.Design and methodsThe design used a randomized crossover trial of two exercise episode durations, involving 17 subjects, which were performed in a university setting. The intervention was exercise on a stationary bicycle for four consecutive days, at 50% of maximal oxygen uptake (determined by heart rate), for episode durations of 10 or 40min. A rest period of 10 days followed before exercise for the alternative duration was performed. The main outcome measure was blinded assessment of blood pressure 24 h after the last exercise episode.ResultsSignificant reductions were found in systolic and diastolic blood pressure after 4 days of 40 min but not after 4 days of 10 min stationary cycling. The reduction in blood pressure was significant for both systolic and diastolic blood pressure for 4 days of 40 min of exercise episodes.ConclusionExercise of moderate intensity on a stationary bicycle for 10 min for 4 days is not effective in lowering blood pressure in comparison with the same exercise for 40 min for 4 days. The experimental design employed in the present study has potential for monitoring the effects of exercise on blood pressure.