The short-term effect of brisk walking at different intensities and durations on systolic blood pressure in middle-aged men

Elevated blood pressure is associated with an increased risk of cardiovascular morbidity and mortality, while exercise studies regularly demonstrate reductions in blood pressure in hypertensive individuals. Reductions in blood pressure are often associated with reductions in body mass and/or increases in aerobic fitness following long-term intervention studies. However, blood pressure can also be reduced immediately following exercise, illustrating that exercise can effect blood pressure independently from body mass losses or increases in aerobic fitness.PURPOSE The purposes of this study were firstly to determine whether walking for 30 minutes at 45% VO2max was sufficient to significantly lower systolic blood pressure (SBP) during the 24 hour post-exercise period compared to a sedentary control session in normo-/hypertensive middle-aged men. Secondly, whether increasing the intensity to 65% VO2max or the walking duration to 60 minutes may influence the magnitude and/or duration of any possible effects.METHODS The study included 13 non-smoking middle-aged males (age 59.92 ± 6.64 years; height 1.79 ± 0.05 cm; mass 94.11 ± 11.17 kg) and employed a repeated measures design, including 4 trials: 1) control trial (CON), 2) walk for 30 min at 45% VO2max (3045), 3) walk for 30 min at 65% VO2max (3065) and 4) walk for 60 min at 45% VO2max (6045). SBP was measured pre-walk, immediately post-walk, and 1-hr, 4-hr & 24-hr post-walk.RESULTS There was a significant interaction between walking intensity and time over the course of the 24 hour period, where SBP decreased significantly for at least 4 hours following 3045 (P=0.023), SBP was only significantly lowered at 1 hour postwalk following 3065 (P=0.032) and back to normal by 4 hours, and SBP was lowered for at least 1 hour but less than 4 hours following 6045 (P=0.006). SBP did not change significantly over the 24 hour period following CON and returned to pre values at 24-hr in each treatment.CONCLUSION Walking for 30 minutes at 45% VO2max is an effective therapy for reducing SBP for at least 4 hours in normotensive/mild-hypertensive middle-aged men. Furthermore, this type of activity appears to be more effective than walking at a higher intensity for the same duration or with an increased duration at the same intensity