Mercury spikes don't go easy on blood flow; Link between heat stress and heart attacks

It is common for people with heart disease to constantly monitor their blood pressure during the colder months. The caution is reasonable for a season which gets to see an increase in cardiovascular events around the globe. However, very little is spoken about the effects of heat on a heart beating under the scorching sun.

Too much heat is also harmful for the heart and makes it work even harder, said experts, particularly for those with high cardiovascular risk and the elderly.

This increases the risk of heart attacks, heart arrhythmias (irregular heartbeat), and worsening symptoms of heart failure, particularly during heatwaves where the land temperature is above the average record.

As per the data provided by the AQI website, 98 out of 100 hottest cities in the world are lying within the borders of India.

Amidst these harsh weather conditions, experts are advising caution against the silent impact of heat on public health. The ill effects of excessive heat are not limited to dehydration and fatigue alone, they have warned as heat affects multi organ systems in human beings. 

The trapped heat in your vessels

Excessive heat in the surroundings can meddle with the body's thermoregulation, a process of dissipating heat load off the body to make it work at an optimum temperature. 

A body is comparable to a housekeeper, neatly placing all the things in the house in the same order for smooth operations. No stranger entering the space can alter the arrangement. Likewise, body also maintains an optimum environment called homeostasis, irrespective of the changing external conditions.

Studies suggest that even a spike of 1 degrees Centigrade in the body temperature can initiate vasodilation, a phenomenon causing broadening of the blood vessels, enabling the formation and release of sweat, resulting in an overall cooling effect.

When the extra heat finds its way out, this enables the body to maintain a steady blood pressure.

This escape of heat is governed by natural principles like pressure differences between the body surface and the surrounding atmosphere and also the moisture saturation in the air at the time.  

When the core temperature increases due to external heat, more blood is rushed into the skin tissues for the heat to escape as vapour.

However, when there are already high levels of water in the air, it becomes hard for the sweat to escape because of the lack of pressure difference. 

As a result, the heat gets trapped in the body and this is when it starts to put stress on various bodily processes. 

An article published in the Science Direct explains that as one advances in age, the body’s natural ability to regulate core temperature gets reduced. Their blood vessels lose the natural elasticity to expand when overheated. This could happen because of a developing rigidity in the arterial structure or an existing inflammation in its walls.

In fact, some studies suggest that the aging population loses responsiveness to nitric oxide, a short- lived molecule that plays an important role in thermoregulation. This increases their risk of heart-related injuries during this time.

Disruption in the supply demand cycle

When excess blood flows near the skin, it can lead to dehydration and electrolyte imbalance. 

When there is an alteration in the levels of elements like sodium and potassium, the electric machinery of the heart gets tampered and one can experience arrhythmias (irregular heartbeat). 

Additionally, when the dehydration kicks in, it also increases the heart rate and other cardiac metabolic demands. This increased gap between the demand and energy supply can drain the heart’s pumping machinery, sometimes even rupturing the plaque (deposition in arterial walls) and causing events like heart attack or stroke.

Warm nights can affect sleep

Nights with their lower temperature allows the body to recuperate from the stressors of the day. However, warm nights can disrupt this process and affect sleeping patterns.

Speaking to DH, Dr. Vikramjeet Singh, a senior consultant in Internal Medicine, from Aakash Healthcare said: “Warm nights are a serious concern because the body depends on cooler temperatures to rest and repair. When that does not happen, it leads to poor sleep, constant fatigue, and a higher risk of heat-related illnesses.”

“Over time, this continuous stress weakens immunity and makes people more vulnerable to infections and other health problems. Chronic heat exposure has also been linked to increased systemic inflammatory responses and oxidative stress, which may further compromise immune function and worsen pre-existing comorbidities.”

As per a study quoted by the BBC, heart disease is one of the leading causes of death among the fire-fighters. The study had found that their core temperature remained high for three to four hours after the exposure to excessive heat.