Cold Adaption and Acclimation Tutorial Flashcards
Abroriginal: Environment
- Great diurnal-nocturnal variation in temperature.
Summer: min 22˚C max 37˚C
Winter: min 4˚C max 21˚C
Cold test parametres (Aborigina)
8hr sleep
3-5˚C
0.29-0.34 CLO
Aboriginal: Physiological adaptation to Cold
Greater tolerance of lowering skin and rectal temp. -> 30% reduction in heat conductance.
Oppose cold stress: Increasing insulation via vasoconstriction + Tolerating moderate hypothermia without metabolic compensation.
Shepherd Norwegian Lapps: Environment
Nomadic,
Lack of formal housing (increase cold stress)
- Sleep in poorly heated tents at -25-30˚C.)
Norwegian Lapp shepherds, villagers and white control: night exposure results
White + Villager: Metabolic response and rectal temperature comparable.
Shepherd: 1˚C drop in rectal temp, Smaller metabolic response to cold. Also shepherd foot temp higher than others.
Eskimos: Environment
North America,
Winter: -46˚C min, -31˚C max, no sun
Summer: not above 6˚C. No night.
Eskimos: Technological adaptation (housing):
whale rib rafters, double insulation with seal skin and moss -> traps air (insulation). Underground tunnels with fires (heat rises and heats surrounding houses).
Eskimos: Technological adaptation (clothing):
Most made of caribou: High quality insulation, light and supple.
What CLO dos caribou clothing provide?
7-12 Clo
What is second favourite material of choice for Eskimos?
Polar bear
Eskimos Physiological adaptations - Metabolic rate: What and why?
Higher metabolic rate than white control in hot and cold conditions (13-45% higher)
- not due to thyroid hormones.
mainly due to high protein and fat diet, but that not everything
Eskimos Physiological adaptations - Peripheral temperature: What and why?
Higher peripheral temperature in response to cool stimuli = prevents frostbite and allows hands to be used for hunting etc.
Most likely due to enhanced vascularisation. Have higher [RBC]. (Higher plasma volume and more globulin proteins.)
When do Eskimos acquire acclimation/adaption characteristic to cold adaption?
During growth: the thermoregulatory characteristics of Eskimos reflect the influence of developmental adaptation.
AMA Women divers from Korea: Metabolic rate
BMR inversely proportional to water dive temp. (35% higher than normal). Urine nitrogen normal so changes were not cause by different in diet.
AMA Women divers from Korea: Shiver - Results and What does this indicate?
Started shivering at 28.2˚C, not 29.9˚C like control group. = Lower shivering threshold for cotton swimsuit ladies (Not diving suit ladies in the 80’s)
- This indicates that adaptation of low shiver rates in cotton swimmers returned to control levels (non-diver levels) at the introduction of the proper diving suit.
