Delayed Hypoalgesia to a Heat Stimulus is Induced by Eccentric Exercise and is Greater for Red- than Dark-Haired Women

Abstract

AbstractObjectives: This study sought to examine the potential delayed effect of eccentric exercise on pain perceptions of heat stimuli presented to red-haired and dark-haired women.Methods: Healthy college-aged women capable of physical exercise were sought for participation in the study. They were to assess pain intensity and unpleasantness of thermal stimuli [at 45, 47 and 49 °C] applied to their forearm and posterior lower leg before and 24 and 48 h after 18 eccentric actions of the non-dominant elbow flexors at an intensity of maximal voluntary concentric contraction strength. Women of similar age and ability served as controls and the exercise for the controls (n=6) was concentric exercise, resulting in little or no muscle injury.Results: Eighteen healthy adult women participated. Twelve [five with bright red hair and five with dark hair] subjects performed eccentric exercise. At 24- and 48-h after the eccentric exercise, the volume of the exercised arm increased by 2.2% [±1.5%] and by 5.0% [±2.2%],...