Explained|Heatwave across India: What can extreme heat do to the body?

India is topping the global heat charts with many of its cities ranking the highest on temperature scale as per the data provided by Air Quality Index. The findings suggest a heat crisis hitting the country with the most affected cities being in Bihar, West Bengal, Odisha and Uttar Pradesh, recording temperatures as high as 43 degrees Celsius. 

Heatwaves are understood as periods with daily temperatures exceeding the historical average of a particular region.

As per reports, there is also a notable surge in sales of air conditioners in Bengaluru as the temperature came close to 37 degrees Celsius. The soaring temperature is very unlikely for a city known for its moderate climate.

The Indian Meteorological Department (IMD) also notified that the seasonal rains in Bengaluru will be delayed by a week.

As per NDTV, the prevalent heatwave is likely to increase medical costs and shrink the economic growth.

While the ill effects of a heatwave are assumed to be limited to skin health and hydration, doctors claim otherwise. 

As per experts, extreme heat can affect the body in multiple ways, far beyond dehydration or fatigue.

Heat and heart health

Excessive heat can make the heart work harder, posing risk for those with pre-existing cardiovascular conditions.

As the body temperature rises, the blood vessels expand causing the blood pressure to drop. This causes the heart to pump the blood harder throughout the body up to the extremities. This can cause significant strain on the heart muscles, particularly among the aged and those with chronic circulatory diseases.

Speaking to DH, Dr. Charu Dutt Arora, a physician from Asian Hospital said: “Warm nights are a serious concern for the body as it depends on cooler temperatures for rest and repair. If the body fails to get enough rest, it can result in chronic fatigue and increased risk of heart-related diseases. Continuous stress on the body also weakens the immunity, a person becomes more susceptible to infections. Extreme heat is also linked to systemic inflammatory responses and oxidative stress.”

As per a study, excessive heat also impairs the thermoregulatory function of the body, particularly among the aged who aren’t able to easily adapt to the temperature changes.

People living with obesity are at higher risk of facing thermal discomfort, the study cited.

In fact, excessive heat can also impact the function of the kidneys and aggravate metabolic irregularities.

“When the body loses too much fluids, the kidneys get affected directly. More people with kidney stones and urinary infections knock at our doors. Heat stress can also result in electrolyte imbalances, particularly sodium and potassium depletion, further impairing the neuromuscular function,” said Dr. Arora.

Heat and fertility

For production of sperms, the optimal testicular temperature must be 3 and 7 degrees Celsius below the body temperature.

These temperature conditions are essential for spermatogenesis, the process through which sperms are formed.

A study done on men working as welders, bakers and iron workers showed that their seminal quality was lesser than those in administrative jobs.

Speaking to DH, Dr. Vineet Malhotra, head of urology and director at VNA hospital said: “Too much heat is a serious but often overlooked risk factor in male infertility. The testicles need a cooler environment to produce sperms in comparison to the body. Even a slight increase in temperature can affect the numbers and quality of sperms. If the body remains exposed to high heat over an extended period, the risk increases for low quality sperms, genetic mutations and infertility in men.”

In fact, studies suggest that placing an overheated laptop or mobile phone on the lap for prolonged periods can have similar effects on the testes.

Likewise, excessive heat causes hormonal imbalances in women, leading to irregular periods, poor egg quality and implantation difficulties in those trying to conceive.

Skin and gut disorders

As per a study published in the National Library of Medicine, when the gastrointestinal tract comes into contact with too much heat, it can cause stress on the intestines.

Very high temperatures can reduce oxygen in the intestines, enabling a harmful imbalance between unstable reactive molecules and the body’s natural tendency to neutralize them. This increases the likelihood of the gut lining getting damaged and inflamed. In extreme cases, it can cause heat stroke and other metabolic complications.

Excessive heat can also alter the gut microbiome, leading to constipation, bloating and decreased digestive function.

Other than that, heat stress also flares up in the form of skin damage, including heat rash, unusual acne breakouts, tanning, pigmentation, sun burn and other serious conditions.

As per experts, heat is no longer a weather condition but a public health threat affecting the body in multiple ways.