Exercise-induced hypoalgesia is not influenced by physical activity type and amount

Physical activity (PA), especially vigorous-intensity PA, has been shown to be related to pain sensitivity. The relationship among PA levels and PA types on endogenous pain inhibition after exercise, termed exercise-induced hypoalgesia (EIH), remains unclear. Purpose: This studied examined the EIH response to pressure stimuli among college-age women of differing activity levels. Methods: Fifty women were tested. Pressure pain threshold (PPT) values were assessed before and immediately after isometric handgrip exercise to exhaustion in the right and left forearms. Participant's PA levels were assessed by wearing an accelerometer for seven consecutive days during waking hours, excluding water activities. Participants were classified into four PA groups: met the American College of Sports Medicine aerobic recommendations (AERO), met aerobic and resistance training recommendations (AERO + RT), insufficiently aerobically active but resistance trained (RT), and insufficiently active (IA) based on their measured and self-reported PA level and type. Results: AERO and AERO + RT had greater vigorous (P < 0.001) and total PA (P < 0.001) compared with RT and IA. EIH was observed for PPT in both right and left arms (P < 0.001), with PPT increasing 7.7% (529 +/- 236 vs 569 +/- 235 kPa) and 7.0% (529 +/- 299 vs 571 +/- 250 kPa) in the right and left forearms, respectively. EIH did not differ among activity groups (P = 0.82). PPT values were found to be inversely related to vigorous-intensity PA (r = -0.29). Conclusions: PA levels and types had no effect on endogenous pain inhibition after exercise in college-age women.