Does light physical activity reduce blood pressure responses to laboratory stressors?

Individuals exhibiting exaggerated blood pressure responses to stress are at increased risk for later cardiovascular disease. Engagement in brief bouts of moderate-to-vigorous physical activity may reduce instances of these exaggerated blood pressure responses. While observational work has shown that periods of light physical activity may also be associated with reduced blood pressure responses to stress in daily life, the few experimental studies involving light physical activity have methodological limitations that temper conclusions. The current investigation sought to understand the effects of brief bouts of light physical activity on blood pressure responses to psychological stress. In a between-person, single-session experimental design, 179 healthy, young adults were randomized to 15 min of light physical activity, moderate physical activity, or sitting before engaging in a 10-min computerized Stroop Color-Word Interference Task. Blood pressure readings were collected throughout the study session. Surprisingly, the light physical activity participants showed higher systolic blood pressure responses to stress than control participants by 2.9 mmHg (F (2, 174) = 3.49, η_p ²  = 0.038, p = .03), whereas no significant differences were shown between moderate physical activity and control groups (F (2, 174) = 2.59, η_p ²  = 0.028, p = .078). These findings show that light physical activity may not be related to reduced blood pressure responses to stress in an experimental session involving healthy, college-aged adults and question the extent to which brief bouts of physical activity may reduce acute blood pressure responses to stress.