Heat index should be communicated to the public New Delhi: May 20th 2016: ‘Heat index’ measures the combined effects of temperature and humidity on the ability of the body to lose heat. It determines how hot it really feels. Periods of high heat index adversely affect human health. Elaborating on this, Padma Shri Awardee Dr KK Aggarwal – Honorary Secretary General IMA & President Heart Care Foundation of India explained that the human body normally cools itself by sweating through evaporation, which carries heat away from the body. But, high relative humidity reduces the evaporation rate and so heat is removed from the body at a lower rate causing it to retain more heat than it would in dry air. As a result, the body temperature increases leading to heat-related illnesses such as heat exhaustion, heat cramps and heat stroke. ‘Heat cramps’ is the mildest form of heat disorder, presenting with cramps due to salt and water dehydration. ‘Heat exhaustion’ is a milder form of heat disorder where sweating is still present. But, ‘heat stroke’ can be lethal if not diagnosed and treated in time. Patients with heat stroke manifest with high fever, dehydration and absence of sweating. The rectal temperature often shoots more than 106oF. Oral and axillary temperatures may not be reliable in such situations. The affected person may be dehydrated to up to 8 to 10 litres of fluid. • This summer, with temperatures already crossing 44.60C, cases of heat stroke are likely to increase in the coming days. • Sportspersons should avoid workouts during peak sun hours and should take adequate fluids to prevent dehydration. Salted lemon water and mango ‘panna’ are the drinks of choice. • Heat stroke is common in elderly and in people who take anti-allergic tablets. • Altered consciousness in a patient with fever should make one suspect underlying heat disorders. • One may lose 500 to 1000 ml of fluids everyday due to summer sweating. This amount, therefore, may need to be taken extra. However, patients with kidney diseases or heart failure need to consult their doctors to decide the amount of extra fluid they need to take. • Absence or presence of sweating can be detected by armpit test. A dry armpit may mean severe dehydration. • In summer, everyone should pass urine once in 8 hours. Not passing urine in 8 hours may mean severe dehydration. • One should avoid eating cut-open fruits and vegetables during this season to prevent disorders like jaundice, typhoid, gastroenteritis and cholera.