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I.9.7 Man’s physiological responses to environmental stresses: hot desert

Characteristics of Arid / Hot Desert Climate

  • <100 MM rainfall
  • Dry and random distribution of rainfall


  • Heat – Very high temperatures
  • Water


  • Diminished pulse rate
  • Lower rectal temperatures
  • Increased sweating
  • Decrease in salt concentration of sweat
  • Decrease in volume of urine
  • Taller body sizes
  • Slender bodes with no fat
  • Aridity – Nomadic activity
  • Clothing and Shelter
  • Genetic adaptations
      • Bergmans law- Body size
      • Allen  law- Body shape
  • Cultural adaptation

    Cultural is a most potent paper in hands of human race. It distinguishes humans from other animals to survive in an favourable climatic conditions. In the recent past houses in desert are used to keep the inside cool even during maximum date time it. Clothing in desert like conditions usually covers almost all body so as to reduce radiation. In hot wet climatic conditions the houses are open and closing is minimum to promote sweat evaporation.

    eg. Hunters and gatherers tend to restrict physical activities during Mid day in hot climates

  • The desert-adapted person can sweat freely but must deal with the water loss involved; hence, he is usually thin but not tall. This adaptation minimizes both water needs and water loss. Skin pigmentation is moderate since extreme pigmentation is good protection from the sun but allows absorption of heat, which must be lost by sweating. Adaptation to night cold is also common in desert-adapted people.

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