From dehydration, heat cramps, heat exhaustion and to more serious ones like heat stroke, as the mercury soars, the number of people suffering from heat-related health conditions goes up.

With parts of north and central India in the grip of a heat-wave, doctors warn against not keeping body well-hydrated in this weather.

Excessive loss of salt and minerals in this hot weather can cause the body to dehydrate severely. Usually, the body sweats to maintain normal temperature, however, in extremely hot weather, this mechanism does not work as well and the body feels exhausted even after slight exertion.

Heat cramps are the least serious of the three and usually occur if there is intense physical exertion. Drinking a couple of litres of water can usually prevent them.

Heat exhaustion is the most common, and symptoms include weak, rapid pulse; low blood pressure; headache; nausea; dizziness etc. If you have these symptoms, do not waste time in seeing a doctor.

It is the heat stroke that is the most serious heat-related illness, and can even turn fatal. Symptoms include extremely high body temperature, burning sensation in the skin, no sweating, rapid and strong pulse, throbbing headache, dizziness, nausea, disorientation and unconsciousness.

People who are above 60 years of age, young children, obese people and those with underlying medical conditions such as high blood pressure, diabetes etc are at a higher risk of collapsing.

“This heat can be life-threatening in severe cases, especially among older persons, when the lost water is not replenished immediately,” said Dr AB Dey, head of geriatrics department, All India Institute of Medical Sciences (AIIMS).

Doctors advise avoiding direct sun exposure, especially during peak hours.

“It is best to avoid sun between 11am and 4pm. But if you must step out then drink at least a couple of glasses of water immediately before you leave home. Carry a water bottle and keep sipping a glass of water every hour. To replenish lost salts and minerals, take butter milk, coconut water or lime water,” said Dr Rommel Tickoo, senior consultant, internal medicine, Max Super-specialty Hospital, Saket.

Also, covering the head with wet towel, or an umbrella helps in minimizing the sun damage.

Wearing loose, light-coloured clothes also helps minimizing the side-effects of getting exposed to extreme heat.

The scorching sun is equally bad for the eyes as direct exposure can cause burning sensation and dryness of eyes. Keeping eyes covered while going out by wearing wide-rimmed sunglasses helps.

“People can get heat-related allergies that cause dry eyes. Sunglasses do help but the glasses should be of good quality that has certified ultraviolet protection, otherwise impurities in the body of the glass can do harm,” warns Dr Mahipal S Sachdev, director, Centre for Sight chain of eye hospitals.

How to protect against heat-related illness

*Drink cool, non-alcoholic, non-caffeinated beverages. Caffeine, found in tea coffee and colas and alcohol tend to dehydrate

*Avoid extremely cold liquids as they can cause stomach cramps

*Drink a glass of water every two hours even if you are not thirsty, and every hour if you are out in the sun.

*Start your day with a couple of glasses of water.

*While exercising take a sip of a mixture of lemon water, sugar and salt every 15 minutes.

*Avoid peak sun hours, between 12pm and 3pm, if you must go out then take plenty of fluids before stepping out.

*Immediately before stepping out of the house, drink a couple of glasses of water

*Carry a bottle and sip frequently; at least a glass every hour when in the sun

*Increase your overall fluid in-take in summers. A minimum of 3-4 litres in 24 hours

*Munch on food items that have high water content such as watermelon, pineapple, cucumber etc

*Take a cold bath if you feel very hot

*Wear lose, lightweight and light-coloured clothes

*Avoid strenuous activity during the day

*Wear a wide-brimmed hat, or use an umbrella if going out