So the water level must be kept up by drinking water regularly, and not only when we are thirsty. Thirst and satiety govern water intake, but unfortunately, there is a time lag between the actual loss of water and signals of thirst. It is thus vital to be alert and more so in summer.

• Avoiding heatstroke

If you are sweating excessively, drink water even if you are not thirsty. Loss of water as sweat is the body’s mechanism to keep cool. This is what happens in the daytime in summer and we maintain body temperature in the normal range.

Excessive loss of water can take place in two ways due to the heat. In very dry and hot weather, any outdoor exposure to heat causes immediate and excessive water loss, for cooling purposes, through sweating.

But not only heat, humidity too, can cause the body to lose water. Humidity does not allow the evaporation of sweat, so the body is not cooled. As a compensatory mechanism, more sweating takes place in a bid to cool the body.

In both the instances of water loss, adequate and timely ingestion of water as compensation is critical. The danger is that the signals for thirst may occur much after the need for water, so that the body stays heated for some time. This compels the body to react to the build-up in body temperature. The early symptoms are likely to be dry mouth, rapid pulse, fever or increased internal temperature and fainting spells. This is referred to as a heat stroke/sun stroke and is a potentially dangerous condition.

... contd.