• The Contribution of Nitric Oxide to the Skin Blood Flow Response to Exercise in Boys and Men

      Woloschuk, Alexandra; Applied Health Sciences Program
      In response to heat stress, children sweat less than adults. However, little is known about their skin blood flow (SkBF) response. We investigated child-adult differences in SkBF during exercise (30 min at 60% VO2max) and local heating (44℃) in 12 boys (9.71.2 y) and 12 men (22.22.0 y) using laser-Doppler flowmetry and L-NAME to inhibit nitric oxide (NO). The exercise-induced SkBF increase was greater in boys versus men (p=0.03). L-NAME blunted SkBF response during exercise in boys and men (p<0.01) (758±201 to 429±229 percent change from baseline vs. 541.6±167 to 352±109 percent change from baseline, respectively). Boys had a shorter time delay between the onset of exercise and onset of SkBF response compared with men (p<0.01) and L-NAME increased the time delay in boys and men (205±48 to 268±90 s vs. 309±71 to 376±116 s, respectively) (p=0.01). During local heating, SkBF increases were greater in boys versus men (p<0.01) and L-NAME blunted the SkBF response in boys and men (2594±939 to 1630±791 percent change from baseline vs. 1600±605 to 1046±345 percent change from baseline, respectively) (p<0.01). These data suggest that boys experience greater and faster increases in SkBF during exercise and local skin heating compared with men. NO influence on microvasculature and thermoregulatory function was not different between boys and men.