Are women more at risk from heatwaves than men? Here's the answer

When a heatwave hits, most of us reach for a cold drink, draw the curtains and hope for a breeze. For millions of women, extreme heat isn't just uncomfortable, it's a genuine health risk that doesn't get nearly enough attention. The conversation around heatwaves tends to focus on the very young and the very old. Rarely does it zoom in on sex differences: how female biology, hormones, and daily life can make the same 42-degree afternoon more dangerous for a woman than for the man sitting next to her. Here are six reasons women are more at risk from heatwaves than men.

Sweating is the body's first line of defense against heat. When temperatures rise, sweat evaporates from the skin and pulls heat away from the body. It’s like an efficient cooling system. The problem is that research consistently shows women tend to produce less sweat than men, and they also begin sweating at a higher body temperature. That combination means the cooling response kicks in later and works less powerfully. This makes it harder for women to cool down efficiently during extreme heat, particularly when temperatures stay high for long periods.

The female body doesn't run at a fixed internal temperature. During the second half of the menstrual cycle, after ovulation, core body temperature rises by around half a degree Celsius. Research shows that this makes many women feel hotter during the second half of their cycle. In normal conditions this is barely noticeable. During a heatwave, when the body is already struggling to stay cool, that extra internal heat can tip the balance and make symptoms significantly worse.

When the body needs to cool itself, it pumps more blood towards the skin so heat can escape through the surface. Research suggests that women often experience a higher heart rate during heatwaves as the cardiovascular system works harder to manage this process. An elevated heart rate puts greater strain on the heart and circulatory system, which becomes increasingly risky the longer extreme heat lasts. For women with existing heart conditions, this effect is even more significant.

This isn't just biology. It's also about where people spend their time. Globally, women are far more likely to take on caring and domestic responsibilities, which often means spending long hours inside homes that can trap heat. While many workplaces have air conditioning, middle class homes frequently don't. During a heatwave, kitchens, living rooms and bedrooms can reach temperatures well above what's considered safe. Women busy with home responsibilities often can't simply step outside or take a cool break when they need one.

Two of the most significant life stages for women bring their own heat-related complications. During pregnancy, extreme heat can worsen dehydration, raise the risk of preterm labour, and put stress on both mother and baby. Menopause, on the other hand, brings sudden waves of intense heat that can strike at any time and are significantly worsened by high temperatures.

Women are more likely than men to be prescribed certain medications that interfere with how the body handles heat. Antidepressants, antihistamines, and some blood pressure medications can all affect the body's ability to regulate temperature or increase fluid loss. Some of these drugs reduce sweating, while others make the skin more sensitive to the sun. Women who take these medications during a heatwave may find that they overheat faster than expected, or that they become dehydrated more quickly, without necessarily feeling thirsty enough to drink more.

Drinking water consistently throughout the day, keeping living spaces cool with fans or damp towels, and avoiding the hottest part of the day (generally between 11am and 3pm) are all practical steps. Anyone who feels confused, stops sweating despite the heat, or develops a rapid heartbeat should treat it as a medical emergency and seek help immediately. Heat is serious. Understanding who it hits hardest is how we start protecting people better.