Causes of Dehydration and Heat Stress

The human body is comprised of over 60% water. Exposure to hot environments and/or strenuous activity, without adequate hydration may lead to dehydration and heat stress.What causes dehydration? The factors below may specifically contribute to an increased incidence of dehydration and heat stress on work sites.


  • Ambient air temperature & humidity
  • Radiation from hot surfaces
  • Outdoor exposure
  • Confined spaces
  • Lack of mobility and access to cooler environments
  • Isolation from other people
  • Strenuous work over prolonged periods


  • Lack of education about effective hydration and cooling
  • Involuntary dehydration
  • Older adults existing co-morbidities in particular cardiovascular, respiratory and renal dysfunction
  • Lack of acclimatisation


  • No access to an adequate supply of water at regular intervals
  • No use of electrolytes
  • No access to shaded environments
  • Equipment that assists the body in cooling
  • Unpalatability of fluids discouraging fluid consumption