Heatwaves

Guidelines and Recommendations

Strengthening health systems preparedness for heat-related illnesses (HRI) in India
Guidelines on Emergency Cooling for Severe Heat-Related Illnesses
Guidelines on Autopsy Findings in Heat-Related Deaths
Public Health Advisory (Do's and Don'ts): Extreme Heat/Heat Wave 2024 (updated)

What is a Heat Wave?

A Heat Wave is a period of abnormally high temperatures, more than the normal maximum temperature that occurs during the summer season in the North-Western parts of India. Heat Waves typically occur between March and June, and in some rare cases even extend till July. The extreme temperatures and resultant atmospheric conditions adversely affect people living in these regions as they cause physiological stress, sometimes resulting in death.

IMD Criteria for Heat Waves

Heat Wave need not be considered till the maximum temperature of a station reaches at least 40°C for plains and at least 30°C for hilly regions.
For stations with normal maximum temperatures ≤ 40°C: Heat Wave is declared with a temperature departure of 5°C to 6°C, and Severe Heat Wave with a departure of 7°C or more.
For stations with normal maximum temperatures > 40°C: Heat Wave is declared with a departure of 4°C to 5°C, and Severe Heat Wave with a departure of 6°C or more.
If the actual maximum temperature remains 45°C or more, heat waves should be declared regardless of normal maximum temperature.

Higher daily peak temperatures and longer, more intense heat waves are becoming increasingly frequent globally due to climate change. India too is feeling the impact of climate change in terms of increased instances of heat waves which are more intense in nature with each passing year, and have a devastating impact on human health thereby increasing the number of heat wave casualties.

Health Impacts of Heat Waves

The health impacts of Heat Waves typically involve dehydration, heat cramps, heat exhaustion, and/or heat stroke. The signs and symptoms are as follows:

Heat Cramps: Edema (swelling) and Syncope (fainting) generally accompanied by fever below 39°C i.e. 102°F.
Heat Exhaustion: Fatigue, weakness, dizziness, headache, nausea, vomiting, muscle cramps, and sweating.
Heat Stroke: Body temperatures of 40°C i.e. 104°F or more along with delirium, seizures or coma. This is a potential fatal condition.

Recovery and First Aid

If you think someone is suffering from the heat:

Move the person to a cool place under the shade.
Give water or a rehydrating drink (if the person is still conscious).
Fan the person.
Consult a doctor if symptoms worsen or are long-lasting, or if the person is unconscious.
Do not give alcohol, caffeine, or aerated drinks.
Cool the person by putting a cool wet cloth on their face/body.
Loosen clothes for better ventilation.

Heat Wave: Do's & Don'ts

Do's

Avoid going out in the sun, especially between 12:00 noon and 3:00 p.m.
Drink sufficient water and as often as possible, even if not thirsty.
Wear lightweight, light-coloured, loose, and porous cotton clothes.
Use protective goggles, umbrella/hat, shoes, or chappals while going out in the sun.
Avoid strenuous activities when the outside temperature is high. Avoid working outside between 12:00 noon and 3:00 p.m.
While travelling, carry water with you.
Avoid alcohol, tea, coffee, and carbonated soft drinks, which dehydrate the body.
Avoid high-protein food and do not eat stale food.
If you work outside, use a hat or an umbrella and also use a damp cloth on your head, neck, face, and limbs.
Do not leave children or pets in parked vehicles.
If you feel faint or ill, see a doctor immediately.
Use ORS, homemade drinks like lassi, torani (rice water), lemon water, buttermilk, etc., which help to rehydrate the body.
Keep animals in the shade and give them plenty of water to drink.
Keep your home cool, use curtains, shutters, or sunshades, and open windows at night.
Use fans, damp clothing, and take baths in cold water frequently.

Don'ts

Do not go out in the sun unnecessarily, especially during peak heat hours.
Do not consume alcohol, tea, coffee, or carbonated soft drinks during a heat wave.
Do not leave children or pets inside parked vehicles.
Do not eat stale or high-protein food.
Do not delay seeking medical attention if feeling unwell due to heat.

Treatment of Sunstroke

Lay the person in a cool place, under shade. Wipe or wash the body frequently with water.
Pour normal temperature water on the head to bring down body temperature.
Give ORS or lemon sherbet/torani to rehydrate the body.
Take the person immediately to the nearest health centre. Heat strokes can be fatal.

Acclimatisation

People at risk are those who have come from a cooler climate to a hot climate. Such individuals should not move about in open fields for a week until their bodies acclimatize to the heat. They should also drink plenty of water.

Acclimatization is achieved by gradual exposure to the hot environment during a heat wave.

Heat Wave Advisory 2024

Advisory for the State Health Department