[Thermoregulatory reactions of the human body to moderate hypercapnia]

Thermoregulatory reactions to sustained hypercapnia were investigated. Continuous 40-day exposure to hypercapnia (1.1-1.6% CO2 in the breathing air) in a thermoneutral area was accompanied by the development of a cooling effect that took the form of enhanced heat production beginning with exposure day 3. As the exposure to hypercapnia continued, lactate and excessive buffer bases in blood decreased, core temperature and heat content of the body declined. These changes suggest the limiting effect of hypercapnia in the above concentrations on thermogenesis, evidently at the stage of glycolytic ATP resynthesis.