Effects of hyperbaric oxygen on recovery from exercise-induced muscle damage in humans.

OBJECTIVE: To determine whether hyperbaric oxygen (HBO) therapy could accelerate recovery from exercise-induced muscle damage in humans.

DESIGN: Pretest-posttest design with random assignment to either a treatment (HBO) or placebo control (sham) group.

SETTING: University of Alberta and Misericordia Hospital, Edmonton.

PARTICIPANTS: 12 healthy male students (24.2 +/- 3.2 years) who were unaccustomed to strenuous eccentric exercise of the calf muscles.

INTERVENTIONS: All subjects performed a strenuous eccentric exercise protocol designed to elicit muscle damage within the right gastrocnemius muscle. Subjects subsequently received either HBO (100% oxygen at 253 kPa [2.5 ATA] for 60 min; n = 6) or sham (atmospheric air at 132 kPa [1.3 ATA] for 60 min; n = 6) treatment conditions. The first treatment was administered 3-4 hours after damage, with a second and third at 24 and 48 hours after the first, respectively.

MAIN OUTCOME MEASURES: Dependent variables included peak torque at 0.52 radians/s, peak isometric torque, and muscular endurance using isokinetic dynamometry; muscle cross-sectional area using magnetic resonance imaging; inorganic phosphate levels and T2 relaxation time using 31P and 1H magnetic resonance spectroscopy; pain sensation and unpleasantness using the Descriptor Differential Scale. These variables were assessed at baseline and until day 5 postdamage.

RESULTS: There was little evidence of a difference in recovery rate between the HBO and sham groups. Faster recovery was observed in the HBO group only for isometric peak torque and pain sensation and unpleasantness.

CONCLUSIONS: HBO cannot be recommended as an effective method of treatment of this form of muscle injury.