Heat related illness

During very hot and extreme heat conditions, people are at greater risk of health problems. These can be specific heat-related illnesses or a worsening of existing medical problems.

Risk is greatest during heat waves and when the temperature hovers about 5C or more above average for 3 or more days. The risk is increased when high temperatures are combined with increased humidity.

At-risk groups:

  • older people, particularly the frail and those living alone
  • babies and young children
  • people with existing medical conditions, such as heart disease
  • people on certain medications, in particular fluid tablets
  • those on fluid restricted diets
  • people who are on medications for mental health conditions or people who use recreational drugs may be at greater risk.

Read more about preventing heat illness and staying healthy during a heat wave.

Heat related illness

Heat related illness can occur when the body is unable to cool itself adequately. The body normally cools itself by sweating. In some situations, sweating isn't enough and body temperature rises. This can be associated with different effects ranging from a mild heat rash or cramps through to heat exhaustion or the more severe and potentially fatal heat stroke.

People can experience heat related illness during periods of extreme heat in summer. It can also occur in athletes or others during periods of physical exertion.

Heat rash

What to look for What to do
  • Clusters of bumps that look like red pimples or small blisters, usually on the neck and upper chest
  • Most common in young children
  • Move to a cooler place
  • Keep the affected area dry
  • Dusting powder may increase comfort
  • Avoid using ointments and creams

Can lead to heat exhaustion without prompt treatment

What to look for What to do
  • Increased thirst
  • Dry mouth, lips and tongue
  • Dizzy, tired or irritable
  • Headaches
  • Bright or dark yellow urine
  • Less urine than usual
  • Drink small amounts of water regularly
  • Move to a cooler place
  • Seek medical attention if symptoms are severe

Heat cramps
Can be an early warning sign of heat exhaustion

What to look for What to do
    • Muscle pains and spasms, usually in the abdomen, arms or legs
    • Most common in people who sweat a lot during strenuous activity
    • Stop all strenuous activity
    • Rest in a cool, shaded place
    • Increase fluid intake with water, low sugar sports drink or diluted fruit juice
    • After the cramps subside, wait a few hours before exercising strenuously
    • Seek medical attention if cramps continue for more than one hour

    Heat exhaustion
    Can lead to heatstroke without prompt treatment

    What to look for What to do
    • Heavy sweating
    • Heat cramps
    • Paleness
    • Weak or dizzy
    • Nausea or vomiting
    • Fast, weak pulse
    • Headache
    • Rest in a cool, shaded place
    • Have a cool shower or bath, or apply cool, wet towels to the body
    • Loosen tight clothing
    • If fully alert, sip water or suck ice chips
    • Seek medical attention immediately if symptoms are severe, get worse or don't improve with treatment, or last longer than an hour

    This is a medical emergency – call Triple Zero (000) immediately

    What to look for What to do

    As per heat exhaustion, plus:

    • Worsening mental condition
    • Slurred speech, poor coordination
    • Seizures or losing consciousness
    • Call Triple Zero (000) immediately – this is a life-threatening emergency
    • Follow directions of ambulance staff
    • Move to a cool, shaded place
    • Remove excess clothing
    • Immerse in water, spray with hose, or apply wet cloths and fan vigorously

    More information