What are dos and don’ts to deal with a heat wave? How to understand symptoms and treat them?

According to the health ministry, a heatwave condition involves a maximum temperature of at least 40°C or more for plains, 37°C or more for coastal stations, and at least 30°C or more for hilly regions. The following criteria are used to declare a heatwave:

Based on Departure from Normal

Heatwave: Departure from normal is 4.5°C to 6.4°C
Severe Heatwave: Departure from normal is >6.4°C

Based on Actual Maximum Temperature (for plains only)

Heatwave: When the actual maximum temperature ≥ 45°C
Severe Heatwave: When actual maximum temperature ≥47°C

What are the different heat-related illnesses? Why do they occur?

Heat-related illnesses comprise a spectrum of disorders from muscle cramps and heat exhaustion to a more serious medical emergency such as heatstroke. These illnesses occur when there is a disruption in regulating the body’s temperature because heat input from the environment and body metabolism is increased compared with output from the skin —via radiation, evaporation, and convection.

“First and foremost, we must understand the virtues of sweating or cooling down the surface of our skin when environmental temperature exceeds that of the human body. That’s when the blood vessels near the skin open up to soak up the cold. But when sweating doesn’t happen and when you are exposed to high heat, the body’s core temperature increases. This is the time when it starts affecting our organs. With an increased blood flow to the skin cells, there is an increased stress on the heart, causing it to beat rapidly, going up to 10 beats per minute for every 0.5°C rise in core temperature. That’s when you have a racing pulse and a sense of unease. In a bid to wind down the body, the muscle and nerve tissues slow down, causing fatigue, headache, nausea and even vomitting. The worst is the electrolyte balance is completely disrupted, which can be disorienting in elderly patients particularly. If the core body temperature continues to rise past 40°C, then organs start shutting down as body inflammation increases. The heart may go into arrest and kidney functioning might go haywire. This means that toxins cannot be flushed out adequately by a malfunctioning kidney and they build up in the body,” says Dr Tarun Sahani, Senior Consultant, Internal Medicine, Indraprastha Apollo Hospitals, New Delhi.

There are various stages of a heat wave impacting your body.

Heat Stress and Thermoregulation: “When exposed to high temperatures, the body’s natural response is to maintain its core temperature through a process called thermoregulation. Under normal circumstances, the body cools itself through perspiration and evaporation, allowing excess heat to dissipate. However, prolonged exposure to high heat can overwhelm these mechanisms, causing the skin to dry up, leading to heat stress,” explains Dr Sahani.

Dehydration and Electrolyte Imbalance: As the body sweats excessively to cool down, it loses vital fluids and electrolytes. “Dehydration can disrupt the balance of electrolytes such as sodium, potassium and magnesium, which are crucial for the proper functioning of muscles, nerves, and bodily systems. Electrolyte imbalances can result in muscle cramps, weakness, dizziness and even cardiac complications,” adds he.

Heat Exhaustion: If the body’s thermoregulation mechanisms fail to keep up with the excessive heat, heat exhaustion can occur. “This condition is characterised by symptoms such as excessive sweating, fatigue, nausea, dizziness, headache, and a rapid heartbeat. Heat exhaustion is a warning sign that the body is struggling to cope with the heat, and immediate intervention is necessary to prevent it from progressing to heatstroke,” explains Dr Sahani.

Heat stroke: “This happens when prolonged exposure to high heat raises the body’s core temperature to 40 degrees Celsius (104 degrees Fahrenheit). Heatstroke can lead to multiple organ failure and damage, affecting the brain, heart, liver and kidneys. Symptoms include confusion, seizures, loss of consciousness, hot and dry skin, and a rapid, strong pulse. Heatstroke requires immediate medical attention as it can be fatal if not treated promptly,” he adds.

What are signs and the recommended treatment for heat cramps?

During the heat cramps, the patients present themselves with painful, involuntary, spasmodic contractions of the skeletal muscle — the calves, thighs and shoulders. The patient is advised to rest in a relaxed environment; the health ministry also recommends fluid and salt replacement (oral).

What is the clinical presentation of heat exhaustion? What is the recommended treatment?

The patient may have one or more of the following symptoms:

Headache, nausea, vomiting
Malaise, dizziness
Muscle cramps
May progress to heatstroke if fails to improve with treatment

The health ministry recommends the following :

Remove the patient from the heat stress area.
If there is no response to treatment in 30 minutes, then aggressively cool the patient to a core temperature of 39°C

What are symptoms of a heatstroke and what is the recommended treatment?

The patient presents one of the following :

Core body temperature higher than 40 degree celsius
Signs of central nervous system dysfunction with confusion, delirium, seizures, and coma
The health ministry recommends the following:

Remove the patient from the heat stress area.
If there is no response to treatment in 30 minutes, then aggressively cool the patient to the core temperature of 39°C.

What are the dos and don’ts

The health ministry has a comprehensive set of guidelines which can protect everybody.

(1) Stay indoors and in shaded places.

(2) Use umbrella/hat/cap/towel when outside.

(3) Wear thin loose cotton and light coloured garments.

(4) Drink water and salted drinks frequently – lassi, lemon water, fruit juices, ORS (Oral Rehydration Solution). Eat fruits such as water melon, cucumber, lemon, orange etc.

(5) Take frequent cool baths and reduce room temperature: use window shades/curtains, fan, cooler, air conditioner, cross ventilate room, sprinkle water, keep indoor plants.

(6) Those feeling unwell, especially the elderly, children, pregnant women, those with pre-existing medical conditions and outdoor workers, should be immediately shifted to a cooler place, put on minimum clothing, be sponged with cold water, applied ice packs wrapped in cloth, and transported to the nearest health facility.

Don’ts:

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Do not go out in the sun, especially between 12 noon and 3 pm
Avoid strenuous activities when outside in the afternoon.
Avoid drinking alcohol, tea, coffee and carbonated soft drinks
Do not leave children or pets in parked vehicles.
Avoid wearing dark coloured, synthetic and tight clothing.