Pain Relief after Isometric Exercise Is Not Task-Dependent in Older Men and Women

Introduction This study assessed the effect of isometric contractions that varied in intensity and duration on pain perception in adults older than 60 yr. Methods Pain perception was measured in 24 men and women (mean +/- SD age = 72.2 +/- 6.2 yr) using a pressure pain device applied to the right index finger before and after isometric contractions of the left elbow flexor muscles of the following doses: 1) three brief maximal voluntary contractions (MVC), 2) 25% MVC held for 2 min, and 3) 25% MVC held to task failure. Results Older adults reported increased pain thresholds (58 s vs 49 s, P < 0.001) and decreased pain ratings (2.8 vs 3.4, P < 0.001) after exercise, and these changes were similar across all three tasks (P = 0.94 and P = 0.55, respectively). Sex differences were identified with older women reporting greater pain sensitivity (lower pain thresholds [P = 0.01] and higher pain ratings [P = 0.004]) and larger reductions in pain ratings than men (23% vs 9%, P = 0.003) after isometric contractions. Conclusions Older adults experienced similar reductions in pain after several different intensities and durations of isometric contractions. Both older men and women experienced increases in pain threshold, but only older women experienced reductions in pain ratings.