Influence of blood pressure elevations by isometric exercise on pain perception in women

Very little research has been conducted examining the relationship between blood pressure (BP), exercise, and hypoalgesia especially in women, even though research indicates that there is an interaction between pain modulatory and cardiovascular systems. The purpose of this study was to examine if pain perception was altered shortly after brief isometric contractions that caused an associated transient prior elevation in BP. Twenty-three healthy women completed two randomly-assigned sessions consisting of isometric exercise (25% MVC for 1-min and 3-min) and quiet rest. A pressure stimulus was applied to the right forefinger for a maximum of 2-min following isometric exercise and quiet rest. The participants pressed a button indicating pain threshold (PT), and rated the intensity (PR-I) and the unpleasantness (PR-U) using pain rating scales. BP was assessed every 15-s during exercise, quiet rest, and during exposure to the pressure stimulus. Results indicated that systolic and diastolic BP were significantly elevated during exercise, with higher BP following 3-min vs 1-min of exercise. Patterns of responses for PT, however, differed with a small increase in PT following 3-min vs 1-min of isometric exercise (d=0.38) while there was a small decrease in PT following 3-min vs 1-min of quiet rest (d=0.20). PR-I and PR-U were not found to change significantly following isometric exercise or quiet rest. It was concluded that both durations of isometric exercise significantly elevated BP, but these elevations in BP were not associated with a consistent alteration in pain perception in this sample of normotensive women.