In study with participation of 53 healthy men volunteers and infra-red thermograph application we obtained data confirming thermal portrait (i.e. skin temperature distribution in muscle rest conditions with minimal thermoregulatory activation) interrelations with maximal aerobic capacity (r = +0.6) and lactate level after critical muscle load (r = -0.7). Acute regional cooling (by 1 minute feet placing in ice water) led to temperature rise in certain breast and back skin local areas and increase in oxygen uptake, pulmonary ventilation and respiratory coefficient. Moreover lactate level in peripheral blood reduced. Summarizing obtained results we assume brown adipose tissue (BAT) activity influencing on thermal portrait formation in conditions with environmental temperature below thermoneutral. This hypothesis permits to explain negative correlation between skin temperature and body mass index and 2-fold increase in oxygen uptake during acute cold exposure. Nevertheless further investigations are needed to clarify physiological mechanisms providing significant correlation between skin temperatures in rest thermoneutral conditions on the one hand and maximal aerobic capacity, anaerobic threshold and lactate content after critical muscle load on the other hand.