Effects of aerobic exercise on muscular pain sensitivity

Muscular pain sensitivity after aerobic exercise was investigated in ten healthy men aged 20 to 30 years in four tests at five-day intervals to determine if previous aerobic work leads to a hyperalgesic status. The intensity of pain was recorded, by visual analog scale, every 30 seconds after the injection of 1 ml of 10% and of 20% sodium chloride hypertonic solution, both during basal conditions, and 1 ml of 10% sodium chloride hypertonic solution 1 and 60 minutes after 30 minutes of submaximal rectangular exercise. The injection of 10% sodium chloride solution 60 seconds after exercise gave rise to a clear increase in pain, similar to that induced by the 20% sodium chloride solution given during basal condition. This observation shows that submaximal exercise produces a hyperalgesic state in the active muscle. This hyperalgesia probably explains the clinical manifestation of latent algogenic triggers during physical activity.