Does Light Physical Activity Reduce Blood Pressure Responses to Laboratory Stressors?

Previous literature generally suggests that exaggerated blood pressure responses to stress, which is associated with increased risk for later cardiovascular disease (Chida & Steptoe, 2010), can be reduced after engaging in brief bouts of moderate-to-vigorous physical activity (Hamer et al., 2006). Observational work has shown that periods of light physical activity may also be associated with reduced blood pressure responses to stress in daily life (Thomas et al., 2019), however, 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, we randomized 179 healthy, young adults to 15 minutes of light physical activity, moderate physical activity, or sitting before engaging in a 10-minute computerized Stroop Color-Word Interference Task. Blood pressure readings were collected throughout the study session. We hypothesized that participants in the light physical activity group (Hypothesis 1) and moderate physical activity group (Hypothesis 2) would exhibit lower BP responses to stress (BPRS) than the seated control group. Contrary to our hypotheses, the current investigation failed to show significantly reduced BP responses to stress following engagement in light or moderate physical activity relative to seated controls. Surprisingly, participants in the light physical activity group showed higher systolic blood pressure responses to stress than the control participants. 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 light and moderate physical activity may reduce blood pressure responses to stress when measured in an acute experimental session. Future work investigating the relationship between light physical activity and blood pressure responses to stress may be more productive after long-term interventions rather than in acute settings.