Treat the heat like a cardiovascular stress-test. Slow down.
As heatwaves grow more frequent and severe, medical experts are drawing attention to a vulnerability that has long gone unaddressed: women's bodies are physiologically and socioeconomically less equipped to withstand extreme heat than men's. From hormonal fluctuations across the menstrual cycle, pregnancy, and menopause, to lower sweat production and higher insulating body fat, the female body faces a compounding set of disadvantages when temperatures rise. The human cost is already visible — in fainting spells, cardiovascular strain, and sleepless nights — and researchers warn it may extend to higher mortality risk. What is being asked of society now is not merely awareness, but a reckoning with how public health policy has been shaped without women's specific needs at its centre.
- Women's bodies sweat less, run hotter, and are hormonally primed to struggle during heatwaves — a biological reality that medicine has been slow to take seriously.
- Real women are already paying the price: fainting before work shifts, abandoning bras from sweat, sleeping on kitchen floors while heavily pregnant, jolted awake by hot flushes with no relief in sight.
- Menopausal, pregnant, and menstruating women face layered crises simultaneously — their thermoregulatory systems disrupted by the very hormones that define their life stages, all while external temperatures climb.
- Socioeconomic disadvantage tightens the trap: lower-paid jobs, caregiving duties, and longer lifespans mean women have fewer options to rest, cool down, or escape when their bodies most need it.
- Doctors are calling for targeted public health messaging, workplace protections, and women in policy roles — insisting this is not a niche women's issue but a systemic failure with life-or-death consequences.
When a June heatwave passed through the UK, women began writing to the BBC in numbers — describing dizziness, exhaustion, bloating, and fear of the heat still to come. Their experiences pointed to something medical experts have long understood but rarely communicated loudly enough: extreme heat does not affect all bodies equally.
The biology is consequential. Women produce less sweat than men and begin sweating only at higher temperatures, meaning their primary cooling mechanism is slower to activate. They also carry higher core body temperatures and greater body fat, which insulates heat inward rather than releasing it. Hormones compound the problem: estrogen and progesterone, which fluctuate across the menstrual cycle, pregnancy, perimenopause, and menopause, directly regulate the brain's temperature control systems. When those hormones shift — as they constantly do — the body's ability to manage heat is thrown into disarray, placing extra burden on an already-strained cardiovascular system.
The stories women shared made the data human. Michaela Finn, on her period during the heatwave, felt so faint before a work shift that she had to call in sick. Charlie Paddock nearly fainted twice and experienced intense hot flushes. Hilary Serif, 57 and menopausal, described her night flushes during the heatwave as "truly horrendous" — dozing off only to be jolted awake, already overheated, with no relief. Jess Bloom, 35 and heavily pregnant, resorted to sleeping on the kitchen floor and taking cold baths every night just to get through.
Beyond biology, socioeconomic realities deepen the risk. Women are more likely to be lower-paid workers and primary caregivers, limiting their ability to rest or escape the heat. They also live longer on average, meaning more years of exposure to heat stress — and greater susceptibility to conditions like dementia that impair the ability to manage it.
Dr Nighat Arif, an NHS GP specialising in women's health, describes heatwaves as a cardiovascular stress-test for women's bodies and urges practical action: track your cycle, know the signs of heat exhaustion, slow down. But she and her colleagues are also asking for something larger — employer awareness, policy change, and more women in decision-making roles. "This is not a woman's problem," Dr Arif said. "This is a societal problem. If we get it right for women, we get it right for everyone."
The June heatwave had barely passed when the messages started arriving at the BBC. Women describing themselves as overwhelmed, irritable, dizzy, bloated, exhausted. They were bracing for more heat to come, and they were afraid.
Extreme heat affects everyone. But when temperatures spike, women's bodies face a particular kind of strain that men's do not. Dr Nighat Arif, an NHS GP specializing in women's health, describes heatwaves as a "stress-test" for the female cardiovascular system—one that leaves women more vulnerable than men. Dr Cat Pinho-Gomes, an academic public health consultant at UCL's Institute for Global Health, goes further: women may face a marginally higher risk of heat-related death, though researchers need more data to say so with certainty. As climate change makes heatwaves more intense and more frequent, medical experts are pushing for something that has been largely absent: targeted awareness and protection designed specifically for women.
The biology is straightforward but consequential. Women's bodies produce less sweat than men's, and they begin sweating only at higher temperatures. This means the body's primary cooling mechanism is impaired—heat cannot shed as quickly, and the visible signs of strain are fewer. A 2025 study found that women also carry a higher core body temperature and greater body fat percentage than men, which acts as an insulating layer, trapping heat inside. Layer onto this the monthly and lifelong fluctuations of estrogen and progesterone, hormones that directly regulate the brain's temperature control systems. During the menstrual cycle, perimenopause, menopause, pregnancy, and breastfeeding, these hormonal shifts throw the thermoregulatory system into disarray. The cardiovascular system, already working harder in hot weather, bears the full weight of this biological mismatch.
But biology is only part of the story. Socioeconomic circumstances matter enormously. Women are more likely to be lower-paid workers and primary caregivers—roles that limit their ability to rest, hydrate, or escape the heat when their bodies need it most. Age compounds the risk. Women live longer than men on average, which means more years spent vulnerable to heat stress. Older women are also more susceptible to dementia, which can impair the ability to recognize thirst or manage medications like diuretics that increase heat vulnerability.
During the menstrual cycle, the second half brings a rise in progesterone, which elevates core body temperature just as external heat is already climbing. Then menstruation arrives, and estrogen plummets to its lowest point, forcing the heart to work harder to cool the body down. Michaela Finn, from north London, was on her period during the late June heatwave. She bled normally but felt a surge in fatigue, dizziness, anxiety, and sleeplessness. Her work shifts fell on the same days. One morning, showering before her shift, she felt faint and had to call in sick. Her body was exhausted, aching, cramping. Charlie Paddock, 27, nearly fainted twice and experienced intense hot flushes. Jess Allingham, 26, described absolute exhaustion beyond her normal experience and total brain fog. Menstruation also means iron loss, which impairs sleep and oxygen delivery—adding more strain to an already overburdened cardiovascular system.
For menopausal and perimenopausal women, heatwaves amplify an already difficult symptom set. Hot flushes and night sweats, driven by falling estrogen, become more frequent and severe during extreme heat. The same applies to women in chemical or surgical menopause, used to treat hormone-sensitive cancers and conditions like endometriosis. Hilary Serif, 57, from Cheshire, called her hot flushes during the June heatwave "truly horrendous, especially at night." She would doze off only to be jolted awake by a flush, already warm, with no relief. Her HRT helps but does not fully control it. Dr Rosaline West, 41, perimenopausal, said surviving the heatwave "was just about survival." She was regularly changing her underwear and eventually abandoned wearing bras altogether because of the sweatiness and discomfort.
Pregnancy adds another layer of vulnerability. Pregnant women struggle to regulate body temperature due to increased metabolic heat and fluid demands. Progesterone fluctuations in early to mid-pregnancy make the body hotter; later, rising progesterone and estrogen bring temperature back down. The sheer physical burden of carrying another human inside the body increases cardiovascular strain. Research published in the Lancet suggests that heat stress during pregnancy may increase the risk of adverse outcomes for both mother and child, particularly in higher-risk pregnancies. Jess Bloom, 35, expecting a baby at the end of July, described being heavily pregnant in summer as "hell—it's literally hell." She has tried sleeping on the kitchen floor and taking cold baths every night, sometimes with a Mars ice cream for company.
The medical consensus is clear: heat exposure is linked to higher cardiovascular morbidity and mortality, especially among women. During heatwaves, the added strain on the heart can cause blood pressure to drop. Combined with fluid and salt loss from sweating, this leads to heat exhaustion. If blood pressure falls too far, the risk of heart attack rises. Dr Arif's advice is direct: know the signs of heat exhaustion and heat stroke, drink fluids, use fans and cooling methods, exercise before sunrise or after sunset, use sunscreen, track your periods. "Treat the heat like a cardiovascular stress-test," she said. Slow down. Take care of your body. She also called on employers, colleagues, and policymakers to be more mindful of women's heat sensitivity. Dr Pinho-Gomes added that more women need to be sitting at decision tables, in positions of power and influence, where they can shape policy with awareness of women's specific needs. "This is not a woman's problem," Dr Arif said. "This is a societal problem. If we get it right for women, we get it right for everyone."
Citações Notáveis
Being heavily pregnant in the thick of summer, it's hell—it's literally hell— Jess Bloom, 35, expecting a baby
This is not a woman's problem. This is a societal problem. If we get it right for women, we get it right for everyone.— Dr Nighat Arif, NHS GP specializing in women's health
A Conversa do Hearth Outra perspectiva sobre a história
Why does the body's cooling system fail women more than men?
It's not that it fails—it's that it was built differently. Women sweat less and later, so heat doesn't shed as fast. Add in higher body fat and core temperature, and you're carrying extra insulation. Then hormones come in and scramble the thermostat itself.
So it's purely biological?
No. That's the trap. A woman working two jobs as a caregiver can't rest when her body needs it. A woman on a tight budget can't afford to cool her home. Biology loads the gun, but circumstance pulls the trigger.
What happens during a period in a heatwave?
Your progesterone spikes and raises your core temperature right when it's already hot outside. Then your period comes and estrogen crashes, forcing your heart to work even harder to cool you down. You're bleeding, losing iron, losing sleep. Your body is in crisis mode.
And menopause?
Hot flushes and night sweats are already brutal. A heatwave turns them into something else entirely. Women describe it as a double hit—you're already warm, then a flush hits from nowhere, and there's no relief at all.
What do experts want to change?
They want this to stop being invisible. They want workplaces to understand it. They want women in the rooms where climate and health policy gets made, because men won't think to ask these questions.
Is this a women's health issue or a climate issue?
It's both. But the real answer is: it's a power issue. Who decides how we prepare for heatwaves? Whose needs get designed into the solution? That's where the problem lives.