Children are at greater risk than adults of suffering dehydration and heat illness in the hot, humid summer months. Parents must take elementary precautions to keep children safe and cool during summer – Dr. Gita Mathai

Summer holidays are eagerly anticipated by children who look forward to a well-deserved break from school and a chance to play games and sports outdoors. But summer also brings with it sweltering heat and high humidity, causing heat exhaustion, dehydration and heat strokes. Inevitably children are at greater risk than adults of suffering dehydration and heat illness. With summer temperatures in India averaging 37-43° C and periodic heat waves having caused 557 deaths across the country in 2016, it’s vital that parents understand the dangers of dehydration and heat ailments and counsel children to be cool and safe during the hot summer months. 

Children and the elderly are most vulnerable to heat-induced ailments because sweat mechanisms are poorly developed in children under the age of four years and function inefficiently in those above 65. 

Body ‘overheating’ cause and effect

The human body maintains a temperature of 98.6° F to enable smooth functioning of internal organs. If it is hot outside, or if children engage in physical activity, the body temperature begins to rise. As warm blood reaches the brain, it sends signals to blood vessels in the skin causing them to dilate and the body “over-heats”. Heat is further exacerbated if clothes worn are tight, dark and made of synthetic fabrics like nylon and polyester. On the other hand, light coloured clothing made of natural fibres such as cotton helps absorb heat better and allows sweat to evaporate.

When the body overheats, clear beads of sweat form on the skin, coating it in a fine film. As sweat evaporates, the body cools down. But this natural mechanism of fighting heat breaks down if the climate is both hot and sultry. Humidity prevents sweat from evaporating. Adequate fluids must be ingested for sweat to form. 

If the body is not adequately cooled, excessive heat causes painful cramps, usually in the legs. If ignored, this can progress to heat illness or exhaustion resulting in dizziness, palpitations, rapid breathing and fainting. If the body temperature rises to 104° F or higher, a heat stroke can occur, which could prove fatal. The skin becomes hot and dry, sweating mechanisms cease to function and the high temperature affects the brain, prompting seizures. 

Therefore, it’s vitally important that the human body is optimally hydrated to replenish the fluids lost in sweat. Sweat contains electrolytes, which are essential for important chemical reactions in the body. During dehydration, electrolytes are lost and must be replenished through rehydration. Neglect can result in hyponatremia (low sodium) or “water intoxication,” which can cause headaches, fatigue, muscle cramps, stomach ailments, and in extreme cases, brain swelling and even death. 

Rehydration 

The best way to rehydrate the human body is to combine water with a light meal. I also recommend lightly salted buttermilk, lime juice, tender coconut water or commercially available correctly reconstituted ORS solutions. 
Sports drinks are unsuitable for rehydrating children because their mineral and electrolyte composition is prepared for adults. Children’s kidneys are also less mature and unable to correct electrolyte imbalances. Moreover aerated fizzy drinks must be avoided as they are hypertonic (a solution with higher salt concentration than normal body cells so that water is drawn out of the cells by osmosis) as is glucose water, tea, coffee and alcohol. These fluids aggravate dehydration.  

Rehydration is best with:

* Coconut water as it contains carbohydrates and electrolytes without added sugar and preservatives
* Diluted, lightly salted buttermilk
* Freshly squeezed lemon in water with salt and sugar or honey
* Children playing sports need between 15-30 ml of fluids for every 0.5 kg of body weight per day.

First Aid for dehydration/heat exhaustion

If a person is suffering heat exhaustion:

* Rest her in a cool shaded area
* Remove excess or unnecessary clothes
* If indoors, switch on the fan
* Sponge down with tepid tap water (not cold water from the fridge)
* Feed salted fluids. Add 1 level tsp (5 gm) salt to 1 litre of water or make homemade ORS with six level teaspoons of sugar and half a teaspoon of salt in one litre of boiled cooled water. 

Skin ailments

Summer heat not only prompts exhaustion but also prickly heat with red goosebumps that itch intolerably and rapidly spread all over the body making the skin look like bitter gourd. This occurs because moist dirt blocks sweat pores and the skin is secondarily infected with bacteria. Commonly, talcum powder is used for prickly heat. But it should be avoided as it aggravates the problem. Its combination of ground zinc stearate and silicates mixes with sweat to form a chalky precipitate which further blocks skin pores.

Moreover, talcum powder, if applied to the groin and genital areas, can migrate through the vagina, uterus, and fallopian tubes to the ovary where it could introduce carcinogens. Airborne inhaled talc can also cause pneumonia or inflammation and swelling of the airways which can be fatal for infants. Therefore the best way to tackle prickly heat is to bathe twice a day and apply soap with a towel, herbal or plastic scrubber, and not directly to the skin.

Travel smart

Families often travel during the summer holidays. To ensure a healthy and happy holiday:

* Avoid eating/drinking at roadside eateries 
* Drink only bottled mineral water 
* Ensure children wear light colour clothing as light colours absorb heat and allow sweat to evaporate.
* Rehydrate with coconut water, buttermilk and/or lemon juice 
* Remain indoors during the hottest part of the day (between 12 and 3 p.m) or use caps and umbrellas
* Ensure that immunisations of children are up-to-date. Typhoid boosters must be taken every three years after the age of two, and ensure that two injections — taken six months apart — are administered to children to immunise them for life against Hepatitis A (jaundice).

(Dr. Gita Mathai is a Vellore-based paediatrician and author of Staying Healthy in Modern India)