Hoffman MD, Shepanski MA, Ruble SB, Valic Z, Buckwalter JB, Clifford PS.

Department of Physical Medicine and Rehabilitation, Veterans Affairs Medical Center and Medical College of Wisconsin, WI, USA. martin.hoffman@med.va.gov

OBJECTIVE: To examine how exercise-induced analgesia is affected by the duration and intensity of aerobic exercise. DESIGN: Repeated-measures design. SETTING: Exercise science laboratory. PARTICIPANTS: Convenience sample of 12 healthy male and female volunteers (mean age +/- standard deviation, 32+/-9 y). INTERVENTIONS: Pain ratings were assessed before and at 5 and 30 minutes after treadmill exercise of 10 minutes at 75% maximal oxygen uptake (Vo(2)max), 30 minutes at 50% Vo(2)max, and 30 minutes at 75% Vo(2)max (randomized order and no less than 48 h between each bout). MAIN OUTCOME MEASURES: Pain ratings were measured on a visual analog scale at 10-second intervals during a 2-minute pressure-pain stimulus to the nondominant index finger. RESULTS: Pain ratings were significantly decreased (P<.05) from pre-exercise values 5 minutes after 30 minutes of exercise at 75% Vo(2)max but returned toward baseline by 30 minutes after exercise. There were no significant changes in pain ratings after 10 minutes of exercise or after exercise at 50% Vo(2)max. CONCLUSIONS: There are thresholds for both the intensity (>50% Vo(2)max) and duration (>10 min) of exercise required to elicit exercise analgesia.

Publication Types:

• Clinical Trial
• Randomized Controlled Trial
• Research Support, Non-U.S. Gov’t
• Research Support, U.S. Gov’t, Non-P.H.S.

PMID: 15241771 [PubMed – indexed for MEDLINE]