Drink ORS regularly so that the electrolytes in your body will replenish and always stay hydrated especially when you're outside drink a minimum of 3.5-4 liters of water per day when you're in the sun and preferably one liter of that should be ORS as you will excessively sweat in the heat and will cause loss of electrolytes. Stay in the shade whenever possible and if you feel the heat is increasing try and apply ice over the forehead, nape of your neck, armpits and groin.