The purpose was to examine the effect of isometric handgrip exercise with and without blood flow restriction on exercise-induced hypoalgesia at a local and non-local site, and its underlying mechanisms. Sixty participants (21 males & 39 females, 18-35 years old) completed 3 trials: four sets of 2-minute isometric handgrip exercise at 30% of maximum handgrip strength; isometric handgrip exercise with blood flow restriction at 50% of arterial occlusion pressure; and a non-exercise time-matched control. Pain thresholds increased similarly in both exercise conditions at a local (exercise conditions: ~0.45 kg/cm2, control: ~-0.04 kg/cm2) and non-local site (exercise conditions: ~0.37 kg/cm2, control: ~-0.16 kg/cm2). Blood flow restriction induced greater feelings of discomfort compared to exercise alone [median difference (95% credible interval) of 4.5 (0.5, 8.6) arbitrary units]. Blood pressure increased immediately after exercise (systolic: 10.3 mmHg, diastolic: 7.7 mmHg) and decreased in recovery. There was no within participant correlation between changes in discomfort and pressure pain threshold. A bout of isometric handgrip exercise with or without blood flow restriction can provide exercise-induced hypoalgesia at a local and non-local site. However, discomfort and changes in systolic blood pressure do not explain this response.
Keywords: Analgesia; pain perception; pain sensitivity; pain threshold.