The Health Department has sounded caution that the current heat wave across districts and the sudden increase in ambient temperature can result in extreme heat stress or heat exhaustion and in worst cases, heat stroke, which could be a medical emergency.

With deaths attributed to heat stroke and dehydration being reported from several districts, experts point out that the sudden spike in atmospheric temperature has left people vulnerable due to the lack of climatic acclimatisation, which can upset all natural defence mechanisms of the body for heat dissipation.

“It is only in the past few years that Kerala has been experiencing the effects of heat wave. In the northern parts of the country, people are better acclimatised to this condition and they have better ability to dissipate and tolerate heat. They have learnt to re-design their work hours by doing outdoor manual labour only in the early morning and late afternoon. They conserve their energy by resting indoors and keeping themselves hydrated and with additional salts. Here, people do not seem to have heeded the guidelines we issued, including the alert about staying indoors when the temperature peaks,” a health official said. Heat acclimatisation can take time and varies from person to person. The human body sweats out to cool the body and maintain the core temperature at about 36.7 degree C. But excessive sweating, especially when one has not been drinking enough water, can lead to dehydration and heavy loss of electrolytes. Consequently, internal temperature rises and this can at times prove fatal. Athletes, agricultural labourers, construction workers, coastal community dwellers, those with mostly outdoor occupations such as traffic cops as well as the children and elderly with various co-morbid conditions are at serious risk of suffering heat exhaustion/ heat stroke.

Sodium depletion

Heat exhaustion occurs because of water depletion or sodium depletion and can present as fatigue, nausea, anxiety, confusion or cardiac arrhythmias. The elderly with co-morbid conditions and who are on medication might be at risk of dehydration in extreme heat even when they are indoors. They have to keep themselves hydrated at regular intervals

“There is also another category of people who are over-hydrated. They would be taking in so much water but might fail to replace the sodium salts they are losing through sweat. Over-hydration can lead to the dilution of salts and other electrolytes and result in hyponatremia, a condition in which sodium (salt) levels become dangerously low. Public should be mindful about these facts too,” a health official said. In extreme heat conditions, the natural decline in renal function in the elderly, salt loss, reduced intake of salt and increased water ingestion could contribute to the development ofhyponatremia in elderly.