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

Abstract

To investigate the effects of a short-term high altitude residence (2 weeks between 4150 m and 6885 m in the Andes) on the general and local cold responses after descent, 11 subjects were submitted both to a whole body standard cold air test (SCAT, dry bulb temperature = 1 degree C, 2 h, nude, at rest) and to a local cold water test of the right upper limb (CWT, 5 degrees C, 5 min) both before and after the expedition. Compared to before the expedition, a lower systolic blood pressure was observed after the high altitude residence [130.00 (SEM 3.35) mm Hg vs 140.40 (SEM 4.74) mm Hg at the end of CWT, P < 0.05] whereas no significant change either in diastolic blood pressure or in heart rate was found. All skin temperatures of the right upper limb were lowered (P < 0.05). During SCAT, body temperatures were unchanged (rectal and mean skin temperature, Tsk) but metabolic heat production was slightly but significantly diminished [110 (SEM 4) W.m-2 vs 125 (SEM 3) W.m-2, P < 0.05] and heat debt increased [11.37 (SEM 1.11) kJ.kg-1 vs 9.30 (SEM 2.30) kJ.kg-1, P < 0.05]. Moreover, the time of onset of continuous shivering (d) was shortened [8.20 (SEM 1.90) min vs 17.30 (SEM 3.60) min, P < 0.05] and the level of Tsk observed at (d) was higher [25.70 (SEM 0.80) degrees C vs 23.57 (SEM 0.78) degrees C, P < 0.05] suggesting an increase in the sensitivity of the thermoregulatory system despite the slight decreased shivering activity observed. It was concluded that general and local cold tolerance were modified by a short-term residence at altitude and that the changes observed were not in accordance with general or (and) local cold adaptation. In contrast, high altitude sojourn could be a risk factor for frostbite of the extremities.

Cold-Induced Peripheral Vasodilation at High Altitudes - A Field Study

“…Mathew et al (1977) and Purkayastha et al (1999) also performed a longitudinal study and observed a strong decrease in CIVD response during the first 2 weeks of high altitude exposure; T max reduced from 9.1 to 5.9°C and 8.7 to 5.9°C, respectively. Savourey et al (1997) found that the mean finger skin temperatures during hand immersion were slightly less after a 2-week stay at altitude (4150 to 6885 m) as compared with the situation before altitude exposure (reduction from 9.3 to 8.0°C). However, Savourey et al (1997) tested their subjects 5 days after the altitude stay, and it is possible that the local acclimatization effect may have been partially lost during this time.…”

“…Savourey et al (1997) found that the mean finger skin temperatures during hand immersion were slightly less after a 2-week stay at altitude (4150 to 6885 m) as compared with the situation before altitude exposure (reduction from 9.3 to 8.0°C). However, Savourey et al (1997) tested their subjects 5 days after the altitude stay, and it is possible that the local acclimatization effect may have been partially lost during this time.…”

“…Consequently, the risk for local cold injuries may be enhanced at altitude. There is no agreement about acclimatization effects on CIVD (Mathew et al, 1977;Savourey et al, 1997).…”

Cold‐induced cutaneous vasoconstriction in humans: Function, dysfunction and the distinctly counterproductive

“…The effects of long-term hypoxia on vasoconstrictor responses to the cold have yielded mixed results, with some studies showing an improved or partly restored vascular response (Daanen & van Ruiten, 2000;Felicijan, Golja, Milcinski, Cheung, & Mekjavic, 2008) and others showing no change (Keramidas, Kolegard, Mekjavic, & Eiken, 2015) or an impaired vascular response (Kounalakis, Keramidas, Amon, Eiken, & Mekjavic, 2017;Savourey et al, 1997) after acclimation to hypoxia. The effects of long-term hypoxia on vasoconstrictor responses to the cold have yielded mixed results, with some studies showing an improved or partly restored vascular response (Daanen & van Ruiten, 2000;Felicijan, Golja, Milcinski, Cheung, & Mekjavic, 2008) and others showing no change (Keramidas, Kolegard, Mekjavic, & Eiken, 2015) or an impaired vascular response (Kounalakis, Keramidas, Amon, Eiken, & Mekjavic, 2017;Savourey et al, 1997) after acclimation to hypoxia.…”

Hand temperature responses to local cooling after a 10‐day confinement to normobaric hypoxia with and without exercise

“…Exposure to high altitude is commonly considered a predisposing environmental factor for local cold injury (Harirchi et al, 2005). Yet, the findings derived from crosssectional studies examining the peripheral vasomotor responses to local cooling, assumed to reflect risk of local cold injury, during and after prolonged hypoxia are equivocal; a few studies have observed an enhancement of local cold tolerance (Nair et al, 1973;Mathew et al, 1977;Rai et al, 1978;Felicijan et al, 2008;Amon et al, 2012), while others have reported either an impairment (Nair et al, 1973;Savourey et al, 1997;Purkayastha et al, 1999;Castellani et al, 2002) or no change (Nair et al, 1973;Mathew et al, 1977;Daanen & van Ruiten, 2000).…”