Over the past few days, most parts of North India have been lashed by hot winds. As the temperature rises above 45 degrees, it becomes challenging for the body to adjust to extreme weather conditions. To cope with extreme heat, our body activates the built-in cooling system of sweating, the heart beats faster, and the blood vessels dilate and allow blood to flow. The body can also be susceptible to heat exhaustion and heat stress which can cause symptoms such as dizziness, fatigue, nausea and muscle aches. In rare cases, excessive heat can result in multiple organ failure. (Also Read: 7 Healthy Ways To Lose Weight During Summer)

“Summer days are here and when the scorching heat of summer pushes the mercury above 45 degrees Celsius (113 degrees Fahrenheit), many interesting changes occur in our bodies. Intense heat takes a toll on our physiology, triggering a range of responses that help. We adapt to these extreme conditions. And survive. As mercury levels rise, sweat becomes our ally, blood vessels dilate like never before, and our heart races to beat the heat,” Dr Parinita Kaur, Senior Consultant- Internal Medicine, Aakash Healthcare, New Delhi, told HT Digital in an interview.
How our bodies react to extreme heat
Dr. Kaur explains how our body adapts to cold temperatures above 45 degrees.
1. Increased sweating
As the mercury rises, our body activates its built-in cooling system – sweat. When temperatures exceed 45 degrees, sweat glands work overtime to release sweat, which evaporates on the skin, creating a cooling effect. Sweating helps regulate body temperature and prevent overheating, but it also causes water and electrolyte loss. It is important to replenish fluids and maintain proper hydration to avoid dehydration and related health complications.
2. Dilation of blood vessels
In response to extreme heat, our blood vessels dilate in a process called vasodilation. When the temperature rises above 45 degrees, the blood vessels near the surface of the skin dilate, allowing them to carry more blood. This expansion facilitates heat dissipation and helps regulate body temperature. However, dilation of blood vessels can sometimes cause a drop in blood pressure, which can cause dizziness or fainting. Staying hydrated and taking breaks in cool weather are essential to support heart health during extreme heat.
3. Increased heart rate
When exposed to temperatures above 45 degrees, our heart rate increases. The body perceives high temperatures as stress and responds by increasing cardiac output to more efficiently deliver oxygen and nutrients to cells. The heart beats faster to maintain an adequate blood supply throughout the body, support the cooling mechanism, and maintain vital organ function. However, people with pre-existing heart conditions should take extra precautions during extreme heat.
4. Skin changes and sunburn
Extended exposure to temperatures above 45 degrees can cause various skin-related problems. Hot weather can make the skin dry, irritated and more susceptible to sunburn. Ultraviolet (UV) radiation from the sun becomes more intense, increasing the risk of sunburn and long-term skin damage. It is important to protect the skin by applying sunscreen, wearing protective clothing, and seeking shade during extreme sun exposure to prevent harmful effects on the skin.
5. Heat exhaustion and heat stroke
Extreme heat can push the body’s temperature-regulating mechanisms to their limits, leading to heat-related illnesses such as heat exhaustion and heat stroke. Heat exhaustion occurs when the body loses significant amounts of water and electrolytes through excessive sweating, resulting in symptoms such as dizziness, fatigue, nausea and muscle aches. If left untreated, heat exhaustion can lead to heatstroke, a life-threatening condition characterized by body temperatures above 40 degrees Celsius (104 degrees Fahrenheit) and severe organ dysfunction. Heatstroke requires immediate medical attention to prevent irreversible damage.
Heat wave diseases
Dr. Sarat Sahu, Senior Consultant – Internal Medicine, Apollo 24|7, and Apollo Hospitals, Sector-26, Noida shared with HT Digital that extreme heat can put us at risk.
1. Dehydration: During intense heat, dehydration is one of the main concerns. When the temperature rises above 45 degrees, your body produces more sweat in an effort to stay cool. So, a lack of fluids can lead to dehydration. Symptoms of dehydration include lightheadedness, dry mouth, fatigue and decreased urine output. Drinking plenty of fluids, especially water, and avoiding alcohol or sugary drinks will help keep you hydrated.
2. Cardiovascular stress: The cardiovascular system can experience severe stress from high temperatures. When the body is exposed to intense heat, blood vessels dilate to help the body release heat, which lowers blood pressure. As the body tries to adjust, it can cause a high heart rate. People who already have heart disease, or other heart conditions such as high blood pressure, are at greater risk. During intense heat, it is important to stay in cool places and limit physical activity.
3. Respiratory problems: Chronic obstructive pulmonary disease (COPD) and asthma are two respiratory disorders that can worsen in extremely hot weather. Hot air can irritate the airways, which can cause bronchospasm and make breathing difficult. Additionally, air pollution levels can increase during heat waves, exacerbating respiratory problems. People with respiratory problems need to take extra care, such as staying indoors in air-conditioned spaces and taking medications as directed.
Tips to protect yourself from heatwave
Dr Ajay Aggarwal, Director and HOD – Internal Medicine, Fortis Hospital Noida says that heat stroke or heat wave can be fatal and precautions should be taken. “Those most at risk for heat-related illness include children and adolescents under four years of age, people 65 and older, people who are overweight, and people who are ill or taking certain medications,” says Dr. Agarwal.
Stay hydrated: Drink plenty of water throughout the day even if you are not thirsty. If exercising, take frequent breaks to hydrate and cool down.
Avoid going out during the hottest parts of the day: Try to stay indoors during peak sun hours, usually between 10 am and 4 pm
Appropriate attire: Wear loose, light-colored clothing made of breathable fabrics such as cotton.
Use sunscreen: Apply sunscreen with a high SPF to protect your skin from the sun’s harmful rays.
calm down: Take a cold shower or bath, use a fan or air conditioner, and use a cool compress to lower your body temperature.
Keep an eye out for others: Check older adults, young children, and people with medical conditions to ensure they stay cool and hydrated.
Avoid strenuous activities: Limit physical activities that can raise your body temperature, especially during the hottest parts of the day.
If you or someone you know experiences symptoms of heatstroke, such as a high body temperature, confusion, dizziness, nausea, or a fast heart rate, seek medical attention immediately.