Experts are calling for better awareness of the heat-related risks to women and more targeted efforts to protect them.
New Delhi, India Jul 9, 2026 ALN: Overwhelmed, irritable, dizzy, bloated, exhausted.
These are the words coming up frequently in comments sent to the BBC by women who, having barely recovered from the record-breaking heat in June, are bracing for more hot weather.
Extreme heat can affect anyone. But heatwaves are a "stress-test" for women's cardiovascular systems, and hit them harder than men, Dr. Nighat Arif, an NHS GP who specializes in women's health, told the BBC.
Women may also be marginally more vulnerable to heatwave-related death than men, though more evidence is needed, said Dr. Cat Pinho-Gomes, an academic public health consultant at UCL's Institute for Global Health.
As climate change drives increasingly intense and frequent heatwaves to the UK, experts are calling for better awareness of the risks to women and more targeted efforts to protect them.
Biologically, it comes down to two things: the natural rise and fall of women's hormone levels and our body's response to heat, which are different from men's, Dr. Arif said.
Women produce less sweat and start sweating at a higher temperature, research shows. This impairs their ability to quickly shed excess heat and makes it harder to judge when their bodies are under burden, simply because they can't see as much sweat on their skin or clothing.
The same research found that women also have a higher core body temperature and body fat percentage than men, which acts like an extra insulating layer.
Now combine this with the natural fluctuations of women's hormones, which already put their brain's temperature regulation systems "out of kilter," according to Dr. Arif.
Levels of oestrogen and progesterone shift most substantially during the menstrual cycle, perimenopause, menopause, pregnancy, and while breastfeeding – which can make it harder to regulate temperature.
All of this is hard work for women's cardiovascular systems, especially in hot weather.
But it's not just biology that puts women more at risk, said Dr. Pinho-Gomes, co-author of a review into sex differences in heatwave-associated deaths.
Socioeconomic circumstances – such as being lower paid or the most likely caregiver to loved ones – can have an even greater impact on how well women are able to look after themselves in hot weather, she said.
Age is another factor. The older one is, the more vulnerable they are to heat – and since women live longer on average than men, they are at greater risk of health impacts, Dr. Pinho-Gomes explained.
Elderly people are also more susceptible to dementia, which can limit the ability to recognize thirst or conditions that require diuretics, used to lower blood pressure – both of which can further expose them to heat stress, she said.
As hormone levels dip and rise throughout the menstrual cycle, so does sensitivity to heat, Dr. Arif explained.
Progesterone rises during the second half of the cycle, before menstruation begins. This can raise core body temperature, adding to the discomfort when it's already hot.
Then the period hits and oestrogen – the hormone which drives the thermoregulatory system – drops to its lowest level, putting more pressure on the heart to cool down.
"I bled a normal amount but noticed a big increase in fatigue, dizziness, anxiety, and sleepless nights," said Michaela Finn, from north London, who was on her period during the late June heatwave.
"My shifts at work landed on the same days, too. During my morning shower, I felt faint; I had to be realistic and call in sick. My body was completely exhausted, aching, and cramping."
Charlie Paddock, 27, from south London, also said she "nearly fainted twice and the hot flushes were unreal," while Jess Allingham, 26, said she was "absolutely exhausted, more than normal," and had "total brain fog."
When women lose blood through menstruation, they also lose iron, which can affect sleep, Dr. Arif highlighted.
Low iron – especially common for women with heavy periods – also affects oxygen delivery, putting additional strain on cardiovascular systems.
Hot flushes and night sweats are common for perimenopausal and menopausal women due to lowering oestrogen, according to Dr. Arif.
The same can happen for women undergoing chemical or surgical menopause, which is used to treat hormone-sensitive cancers and major gynecological conditions.
During a heatwave, women may experience more frequent and severe hot flushes and night sweats, which could be further exacerbated by global warming.
"Truly horrendous, especially at night time," is how Hilary Serif, 57, from Cheshire, characterized her hot flushes during the June heatwave.
"You're dozing off and then it hits you from nowhere. You're already warm, there's no relief at all. It's like a double whammy. The good old HRT helps a lot but doesn't control it."
Dr. Rosaline West, 41, from Kettering, who is perimenopausal, said enduring the heatwave "was just about survival."
"I was regularly changing my underwear, and by the end... my friend and I had just given up on bras altogether because of that sweatiness, that discomfort."
Pregnant women have a harder time regulating body temperature due to increased metabolic heat and fluid needs, making them more prone to heat stress, according to research published earlier this year.
Cue the hormones. Fluctuating progesterone levels during early to mid-pregnancy can make women feel hotter, while levels rise during the latter stages, bringing body temperature back down.
Size also makes a difference. "Obviously, there is more cardiovascular burden on the body the bigger you are, because you're carrying a human inside you," Dr. Arif explained.
The research suggests that heat stress may increase the likelihood of adverse outcomes for both mother and child, particularly in higher-risk pregnancies.
Jess Bloom, 35, is expecting a baby at the end of July. "Being heavily pregnant in the thick of summer, it's hell – it's literally hell," she said.
She's explored sleeping on the kitchen floor and having a cold bath every night. "Sometimes a Mars ice cream would join me," she added.
Heat exposure has been linked to a higher risk of cardiovascular morbidity and mortality, especially among women, a major review of studies on the effects of heat exposure found.
During heatwaves, the added strain on hearts can cause blood pressure to lower, which combined with the loss of fluids and salt from sweating, can lead to heat exhaustion.
If blood pressure drops too low, the risk of heart attacks also rises.
Dr. Arif advised: "Know the signs of heat exhaustion and heat stroke... drink plenty of fluids, have your fans, your cooling stuff. Make sure you do your exercise before sunrise or after sunset. Use sun cream, track your periods.
"Treat the heat like a cardiovascular stress-test," she said. Slow down, take care of your body.
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