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Beware of Heat Stroke

15 May 2023

What is heat stroke?

The human body can regulate internal temperature within safe limits spontaneously. When we get hot, the temperature control centre inside our body will trigger responses such as sweating and increasing breathing rate to cool us down. However, when the environment becomes extremely hot and spontaneous responses cannot effectively cool down our body, heat exhaustion or even heat stroke will occur.

Symptoms of heat exhaustion include giddiness, headache, nausea, shortness of breath and mental confusion. When the body temperature reaches 41°C or higher, the sufferer will have convulsion or become unconscious; and this is heat stroke. Immediately, the body temperature must be brought down and first aid be given, or else the sufferer’s life will be in great danger.

Who is at risk?

Infants and children, the elderly, pregnant women, those with chronic illnesses, such as heart disease or high blood pressure, outdoor/manual workers, and individuals who are overweight are more vulnerable to heat stroke.

Precautionary measures

Pay attention to the weather warnings issued by the Hong Kong Observatory and take the following measures:

  1. Wear loose and light-coloured clothing to reduce heat absorption and facilitate sweat evaporation and heat dissipation.
  2. Bring and drink plenty of water to prevent dehydration.
  3. Avoid consumption of caffeine (e.g. coffee and tea) or alcohol, because they speed up water loss from the body through the urinary system.
  4. Avoid vigorous exercise and prolonged activities such as hiking and trekking, as heat, sweating and exhaustion place additional demands on the body.
  5. Perform outdoor activities in the morning or late afternoon, if possible.
  6. Choose an indoor venue with good ventilation by opening all windows and using fan or air-conditioning. Avoid doing vigorous exercise in a hot or stuffy environment.
  7. Re-schedule work to cooler times of the day if feasible. Otherwise, increase shaded area in the workplace where practicable, and work slowly at first and pick up the pace gradually. Rest at regular intervals in a cool area to recharge yourself.
  8. Do not stay inside a parked vehicle.
  9. Stop the activity immediately if feeling unwell and seek medical advice as soon as possible.