Thermographic evaluation of the relative heat loss by area in man after swimming.

Regional differences in skin temperature (Ts) were determined by infrared radiography in four competitive swimmers of varying body compositions, prior to, after 5 min of immersion in water (Tw) at 23.5 degrees C, and after a 500-m freestyle swim at a training pace. Decreases in skin temperature that correlated with skinfold thickness were seen post-immersion (r = 0.56, p less than 0.05). After swimming, skin temperatures were highest in regions overlying active muscle masses and were independent of skinfold thickness. These regions were the deltoids, trapezius, triceps and biceps brachi, and pectorals. Swimming increased the extent of warmer skin surface areas and gradient Ts-Tw, over which heat loss could occur.