Hydration is important every day, but it takes on increased urgency in the summer months. “Dehydration is the lack of both water and electrolytes, and an effective hydration strategy should involve replacing both,” says Dr. Nikolas Harbord, assistant professor, medicine, nephrology, Icahn School of Medicine at Mount Sinai and site chair of nephrology at Mount Sinai Beth Israel. We talked to the doctor to get the scoop on why it’s vital to get more than your usual eight-a-day when the mercury rises.
Water is your body’s best friend in summer
Why is it especially important to stay hydrated in the summer or hotter weather?
In summer, when the ambient temperature is high, your body adapts by sweating, which cools the body through evaporative heat loss. Prolonged heat exposure, and especially activity in the heat, can lead to liters of fluid loss, greatly increasing the risk of dehydration.
In humid weather, when the air already has increased water vapor, sweating continues without evaporation and there is less cooling. So in addition to dehydration, summer temperatures can lead to heat illness.
How much water should we consume when it’s hot out?
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A hydration strategy should include regular drinking of water in excess of losses in sweat. The amount of fluid loss depends on the level of activity and many other factors, and could be measured by weighing yourself on a scale. More practically, water intake in very hot weather should well exceed the typical intake of eight cups per day.
Are sports drinks a good idea? Can they replace water?
Sports drinks containing carbohydrates and electrolytes in water can be effective for hydration.
Are all liquids hydrating?
While all liquids contain water, alcohol and caffeinated drinks, including caffeinated sports drinks, can dehydrate and should be avoided.
Can you drink too much water? How much is too much, and what happens if you do?
It is possible to drink too much water, and in turn, dilute the dissolved salts in the body, leading to a condition called hyponatremia. Hyponatremia usually results from acute or chronic medical conditions or from medications, but can occur with rapid water intake in excess of 1 liter an hour or more 20 liters in a day. Symptoms of hyponatremia are neurological (nausea, headache, confusion) and the result of brain swelling.
What types of people need more hydration than others?
Athletes exercising in the heat have higher fluid losses and need an aggressive hydration strategy to avoid dehydration and heat cramping. The elderly have a decreased thirst reflex and may not recognize the need for hydration. Young children and infants are also at great risk of dehydration in high heat due to their body composition and diminished thirst.
Who is at risk for dehydration?
Anyone active in the sun with fluid losses in sweat and breath is at risk of dehydration.
What are the signs of dehydration?
Initial signs are tiredness, weakness and headache. More severe signs include decreased urination and muscle cramping.
What should you do if you notice the signs?
Get out of the sun and begin to rehydrate with water and salt.
“If you’re thirsty, you’re already dehydrated.” Is there any truth to that?
This is likely true, as the sensation of thirst accompanies a complex neurological and and hormonal response to the decreased body fluid volume in circulation or an excessive sodium concentration from water loss.