Effect of altitude exposure on thermoregulatory response of man to cold

Abstract

The thermoregulatory responses to 10 degrees C (for 3 h) were investigated in 1) 12 natives from sea level (lowlanders) at 150 m, and on arrival at 3,350 and 4,340 m; 2) 6 of these during a 6-wk sojourn at 4,360 m, and on return to sea level; and 3) 5 natives from each of the two altitudes (highlanders) in their respective habitat, and after descent to 150 m. The cold-induced increase in the rate of O2 consumption (Vo2) of the lowlanders was significantly smaller at both altitudes than at sea level. It did not recover substantially during the 6 wk at altitude, but was restored to its initial rate on return to sea level. By contrast, visible shivering activity was augmented on arrival at altitude. It persisted throughout the 6 wk there, but was greatly depressed on return to sea level, despite the increased Vo2. Mean skin temperatures (Tsk) stabilized in the cold at significantly higher values at altitude. Rectal temperature (Tre) decreased similarly at all altitudes. Vo2 of the highlanders in the cold was significantly greater at sea level than at their resident altitudes, although shivering activity was less intense; Tsk stabilized at significantly lower levels at 150 m than at either altitude. These results indicate that altitude exposure reduces the calorigenic response of man to cold, and that this effect is not moderated by acclimatization to altitude, yet is reversible immediately on descent to sea level. The component of cold thermogenesis which appeared to be reduced by altitude exposure was nonshivering thermogenesis rather than visible shivering.

Moderate hypoxia does not affect the zone of thermal comfort in humans

“…Although studies have reported equivocal findings regarding the effect of hypoxia on autonomic thermoregulation in humans, (Cipriano and Goldman 1975;Blatteis and Lutherer 1976;Robinson and Haymes 1990), the effect on behavioural thermoregulation has largely been ignored. Replicating the protocol of Cabanac (1972), Golja and Mekjavic (2003) investigated the effects of hypoxia on preferred hand temperature during core cooling and found no significant effects.…”

Proceedings of the Physiological Society, 18‐19 September 1987, Cambridge Meeting: Poster Communications

“…Department of Physiology, Marischal College, Aberdeen AB9 lAS An increase in oxygen consumption in the absence of visible shivering has been taken to indicate a non-shivering and non-muscular contribution to human thermogenesis (Batteis & Lutherer, 1976). It is a common subjective experience that shivering is preceded by increased muscle tone, and the present work was carried out to determine the magnitude of the increase and to relate it to oxygen consumption.…”

General and local cold responses in humans after 2 weeks at high altitude

“…The general thermal changes after a high altitude residence have previously been studied by Blatteis and Lutherer (1976) and by Mathew et al (1979). However, results from these studies appear conflicting since Blatteis and Lutherer (1976) have shown that the changes observed at altitude in 6 lowlanders acclimatized during a 6 week sojourn at 4360 m disappeared immediately after descent.…”

“…However, results from these studies appear conflicting since Blatteis and Lutherer (1976) have shown that the changes observed at altitude in 6 lowlanders acclimatized during a 6 week sojourn at 4360 m disappeared immediately after descent. Conversely, Mathew et al (1979) have reported that 18 highlanders presented greater cold tolerance at sea level compared to lowlanders.…”

“…Extensive studies have been carried out on human responses to cold during hypoxia with both whole body cold exposure (Blatteis 1972;Blatteis and Lutherer 1976;Brown et al 1952;Bullard 1961;Cipriano and Goldman 1975;Davis et al 1967;Elsner 1963;Johnston et al 1996;Kottke et al 1948;Mathew et al 1979;Mazess and Larsen 1972;Nair and George 1972) or with local cold exposure of the extremities (Durand et al 1969;Malhotra et al 1976;Mathew et al 1977Mathew et al , 1979Nair et al 1971;Rai et al 1978). However, few studies have been conducted to examine the effects of high altitude residence on physiological responses to cold observed after descent both during whole body or during local exposure of the extremities.…”