Beat the heat: Why hydration is the best hack to face extreme summers
Summary
A balanced intake of water, hydrating foods and low-sugar fluids can help prevent heat-related illnesses this summer
We’re just stepping into April but several parts of India are already suffering heat waves and abnormally high temperatures. As a result, hydration has become a hot topic earlier than usual. As with most vital wellness and health-related matters these days, there is a fair bit of conflicting information out there with no credible source or scientific evidence to support it. “That doesn’t take away from the fact that hydration is critical in fighting extreme heat, as prolonged exposure to high temperatures can increase water loss through sweating, leading to dehydration," says Dr. N.R. Shetty, Consultant, Internal Medicine, Kokilaben Dhirubhai Ambani Hospital, Mumbai.
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A study in the American Journal of Physiology found that even mild dehydration (1-2% body weight loss) can impair cognitive performance and mood. Dehydration can increase the core body temperature and reduce endurance, coordination, and cognitive function, making people more vulnerable to heat-related illnesses including heat exhaustion, dizziness, headache, muscle cramps, fatigue, and even heatstroke in severe cases.
The general advice that has been drummed down to us over the years is that you need to drink three litres of water a day. Now, while general health guidelines do recommend two and three litres of water per day for adults, doctors and health experts unanimously agree that actual hydration needs vary from individual to individual. For example, people with sedentary lifestyles sweat less and may need less water. “A labourer working outdoors in high temperatures will require significantly more water than someone working in an air-conditioned office. While hydration needs vary, it is always advisable to consciously drink enough water to support the body’s essential functions," says Dr. Manisha Arora, director for internal medicine, CK Birla Hospital, New Delhi. Additionally, our body has built-in mechanisms to regulate water balance.
“The antidiuretic hormone (ADH) and renin-angiotensin-aldosterone system (RAAS) work together to retain water when the intake is low. This is why people who drink less water may still function normally… their bodies compensate by concentrating urine and reducing sweat," explains Arora. Shetty further adds that while maintaining hydration should be a conscious effort, “stressing over precise numbers is unnecessary and listening to the body’s natural thirst signals is key."
As for sources for hydration, water is indisputably the best but fluids like tea, coffee, coconut water, ORS, lime water, milk, soups, and water-rich fruits and vegetables like cucumbers and watermelons, too, contribute to our hydration needs. However, not all beverages hydrate equally. “Tea and coffee contribute to hydration, but excessive caffeine (more than 300 mg/day) may have a mild diuretic effect. Soft drinks and energy drinks are not considered beneficial because of their high sugar and caffeine content. Alcohol also does not contribute to hydration as it acts as a diuretic, increasing fluid loss," says Shetty, adding that the best approach is to prioritise drinking plain water and incorporate hydrating foods and low-sugar fluids in your daily diet.
As per the USA’s Centers For Disease Control and Prevention, during a heat wave, however, hydration should be paired with electrolyte replenishment to prevent imbalances, especially for those who sweat excessively.
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Across India, a lot of people also have strong convictions about drinking water temperatures that are beneficial for the body. Cold or ice water, for instance, is viewed with fear as something that causes illnesses such as cold, cough, fever and sore throat. Warm water, on the other hand, is considered good for human health, revered to the point of being considered medicinal if not magical, and seen as a solution to aid weight loss.
Doctors say there is no scientific evidence backing up either claims. “Cold water is generally safe. Drinking cold water does not directly cause illnesses like cough, cold, or fever," says Arora. The common cold is caused by viruses, not by the temperature of water consumed, adds Shetty. But for individuals prone to respiratory issues or allergies, cold water can irritate the throat and trigger coughing. Additionally, if someone is already incubating a virus or bacteria, consuming ice-cold drinks might worsen symptoms by creating an environment where pathogens thrive, explains Arora.
As for the supposed therapeutic qualities of warm water, Shetty dismisses the claims saying, warm water is not “magical," while Arora says that there is no scientific evidence proving that warm water has unique medicinal properties. But both agree that warm water does offer some physiological comfort. “While there’s no universal medicinal property in warm water, it can be beneficial when combined with herbs, lemon, or honey for specific purposes like soothing a sore throat or aiding digestion. However, these effects vary from person to person and are not a substitute for medical treatment," says Shetty. As for warm water aiding weight loss, Arora says, “Warm water’s role in detoxification and weight loss is not scientifically proven. It is a healthy habit, but it should not replace a balanced diet and exercise."
Shrenik Avlani is a writer and editor and the co-author of The Shivfit Way, a book on functional fitness.
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