Sleepless in summer? Blame climate change

As extreme temperature events increase in frequency, duration and magnitude, the human body, which is fairly adaptive when it comes to thermoregulation, may finally be experiencing the impact of climate change. The World Health Organization (WHO) has already warned that exposure to excessive heat has “wide-ranging physiological impacts for all humans, often amplifying existing conditions and resulting in premature death and disability.”

While short-term consequences like heat cramps and exhaustion are fairly noticeable and manageable, we need to be particular about the impact of high heat in people with comorbidities. Dr Rommel Tickoo, director of internal medicine at Max Super Speciality Hospital, Panchsheel Park, says, “While children and senior citizens have always been susceptible, those with diabetes, heart disease and other comorbidities need to keep themselves very well hydrated and maintain optimum electrolyte balance in extreme ambient heat conditions.”

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“Sometimes, too many diuretics (which cause increased urination) may suddenly influence blood pressure levels. And sudden changes interfere with the effectiveness of ongoing medication. Normally, the human body is adaptive to temperature changes and can ride out extreme conditions if it finds a bout of relief in a controlled and cooler environment. But prolonged exposure to sustained high heat, especially for those who have an outdoor profile, raises the risk of a heat stroke,” he added.

What is the tipping point for a heat stroke?

As Dr Tickoo explains, “That happens when the body’s adaptive capacity is challenged so much that it forgets to sweat. We perspire in high heat conditions which cools the body. But once the body’s temperature regulatory mechanism, subjected to unusual heat stress, fails and a person stops perspiring, the body heats up uncontrollably. There is high fever and delirium and conditions worsen very rapidly.”

The real tussle is when the ambient heat and the body’s own internal heat, generated due to metabolic processes, put extra pressure on the body’s regulatory and adaptive capacity. That’s when you get exhausted and complain of cramps, headaches and nausea. It is because of the swift turning point that Dr Tickoo advises special caution for those suffering from chronic conditions like “cardiovascular, respiratory and cerebrovascular disease and diabetes-related conditions.” Simply because a heat stroke impacts both the body’s circulatory and nervous systems. So, if the usual symptoms of exhaustion, nausea, dizziness and cramps continue despite rehydration and rehabilitation, then one should consult a doctor.

How heat can leave you sleepless

A few days ago, a report by the University of Copenhagen set alarm bells ringing as it established how rising night temperatures driven by the climate crisis were cutting the sleep of people across the world. This is the largest study of its kind till date. While we increasingly emphasise good quality sleep in these stressed times for healing and well-being, with global heating raising night temperatures even faster than day temperatures, we are finding it harder to sleep at the right time and are waking up early. The analysis revealed that the average global citizen is already losing 44 hours of sleep a year, leading to 11 nights with less than seven hours’ sleep, still considered a healthy benchmark.

“Long-term impacts of constant exposure to high heat can not only affect sleep but even your immunity and the digestive system,” says Dr Tickoo.

The human body has a circadian rhythm or its own in-built sleep cycle mechanism. Our internal body temperature goes down to help us fall and stay asleep. This happens after the diurnal hours. Post sunset, body processes begin to slow down, simmering down our internal body temperature, winding us down, so to speak. The blood vessels dilate to release heat and the body is primed for rest.

If the ambient temperature is high, then it slows down and interferes with the body’s natural process of cooling down. “That’s how you sleep on and off. You may toss and turn around. You may lie in bed but drift in and out. And then you get tempted to look at your devices which keep you in a wakeful state. Sleep disorders are subtle, long-term effects of high heat,” says Dr Tickoo. Clearly the body’s restorative functions, which require deep sleep, are affected and impact our immunity levels.

How can you mitigate impact?

Of course, we can condition our immediate environment, keeping the room temperature below 32°C during the day and below 24°C during the night. This, according to the WHO, is especially important for infants or people who are over 60 years of age or have chronic health conditions.

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Electric fans provide relief but when the temperature is above 35°C, they may not prevent heat-related illness as they throw back hot air. “That is why it is important to drink fluids and keep ourselves well-hydrated. Of course, everybody knows that they have to avoid time outdoors during the hottest time of the day. But in case that is unavoidable, drink fluids before you set out. Cover yourself appropriately and use sun hats, shades and umbrellas. And once you step indoors, cool off gradually, wash your face and hands before entering an air-conditioned room. Wear loose-fitting clothes for the air to circulate,” advises Dr Tickoo.

As for a diet during the heatwave, he says, “Drink water or fluid frequently but avoid alcohol and too much caffeine and sugar. Eat small meals and eat more often. Avoid foods that are high in protein. Avoid strenuous physical activity. Do not give up walking, but do it during the coolest part of the day, between 4 am and 7 am. If walking late in the evening, keep that between 6 and 7 pm, not later.” And as the WHO says, “keep medicines below 25°C or in the refrigerator (read the storage instructions on the packaging).

The human body may not be prepared for climate change, but mindful living can help us adjust better to our changed environs.

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