Summer Heatwaves or a Silent Health Emergency

We see a sharp rise in temperature across India, since past few years. Summer is no more longer just a warm season which varieties of fruits to enjoy but, has become an emerging health concern season due to climate change and rapid urbanisation. The impact of heatwaves extends beyond fatigue and dehydration, cardiovascular deaths are becoming more common.

Understanding Heatwaves

When the temperature rises significantly above the normal average for a region, that is exceeding 40°C in plains and 30°C in hilly areas, is termed heatwave.

How your body reacts to heat

Your body is structured to function within a temperature range. And, when our body tries to cool down during the heatwaves, the body’s natural ability to regulate the temperature get affected, this condition is called “heat-illness” or hyperthermia.

How heat affects cardiac health

Extreme heat creates an extra stress on the cardiovascular system. And, the stress forces the heart to give extra efforts to regulate body temperature. These efforts develops a strain and increases the chances of heart attacks, irregular heart rhythms (arrhythmias), and worsening heart failure. Radiation and evaporation are the two mechanisms through which the body cools itself. In case of radiation, our blood vessels widen and more blood is redirected towards the skin to release heat into the surrounding air. And, heat is pulled out of skin through sweat which is termed evaporation. But, cooling becomes difficult when it’s too hot and humid because the evaporation process becomes less effective.

So, rise in temperature creates pressure on the heart to circulate two to four times more blood per minute as compared to cooler days. On extremely hot days, which further increases workload on the heart and demands more oxygen. Rise in temperature means excess sweating which causes abnormal heart rhythm due to loss of electrolytes like sodium and potassium.

A dehydrated body can reduce blood volume leading to fluctuations in blood pressure and also thickens the blood causing clot formation, strokes, and stacks. Again, if you are under certain medications like Beta blockers they can further slow down the heart rate and reduce the heart’s ability to increase circulation efficiently, while diuretics can increase fluid loss and raise the risk of dehydration.

Other health impacts due to heat

Other than cardiac health, you may also find complications in kidneys due to fluid loss and electrolyte imbalance. Also, mental health gets affected due to increased irritability, anxiety, disturbed sleep, and reduced concentration.

Metropolitan environments further intensifies the problem due to the “heat island effect,” where concrete infrastructure and limited green cover trap heat, making cities significantly warmer than surrounding areas. Urban lacks access to cooling due to poor ventilation which increases the heatwave risks.

Age-group at risk

Children, older adults, pregnant women, pre-existing conditions such as diabetes, hypertension, kidney disease, or cardiovascular disorders become more vulnerable to heatwaves. And, some outdoor workers are more prone to risk during heatwaves.

Precautionary measures

• Avoid outdoor exposure during peak hours mostly in the afternoon.
• Prefer wearing loose, light-coloured cotton clothing, using hats or umbrellas.
• Keep yourself hydrated by drinking adequate amount of water. And, you can also opt for fluids such as oral rehydration solutions (ORS), coconut water, buttermilk, and water-rich fruits like watermelon and cucumber which helps maintaining hydration, electrolyte balance, and also keeps your gut healthy.
• Avoid alcohol
• Don’t ignore subtle symptoms like dizziness, breathlessness, excessive fatigue.

Warning signs

Subtle symptoms which includes dizziness, high fever, brain fog, fainting, or less urination it becomes important to consult your doctor immediately.

By Dr. M Ravi Kumar, Senior Consultant – Internal Medicine, Sakra World Hospital, Bengaluru