White Coat, Black Art26:30Hot as hell
Britnee Miazek didn’t immediately connect the ending of her period with her job as a second-year apprentice at a metalworking shop in Sault Ste. Marie, Ontario.
It was only after three months of working in 2023 in positions related to operating coke ovens used in the steel production process that the 35-year-old began to notice certain patterns.
“As soon as I changed jobs … my body started producing periods again,” Miazek said.
She describes the coke ovens outside as “as hot as you can get” and believes the extreme heat they generate may have been the cause of her periods stopping.
Miazek went to a doctor at the clinic, who referred her to a gynecologist in Toronto, but she was unable to go to the appointment because the weather made it difficult to fly.
“I just did the job that was given to me, and I just had to work hard to figure something out,” she told CBC host Dr. Brian Goldman White Coat, Black Art.
As our planet heats up, people like Miazek who work in extremely high outdoor temperatures will be more exposed to heat, increasing the risk of heat-related health problems. But endocrinologists and scientists say there’s still a lot to learn about how a woman’s body copes with extreme heat, especially during life-changing times like perimenopause and pregnancy.
The health effects of heatwaves caused by climate change are already visible in Canada and other places around the world.
“We are witnessing a real epidemic of long-term clinical problems,” said Stephen Cheung, a professor of kinesiotherapy at Brock University in Ontario.
He specifically mentioned heart problems, including arrhythmia and coronary artery disease, as well as kidney problems.
Experts in The Center for Disease Control (CDC) in the US says that Excess heat can also negatively impact female and male fertility and overall reproductive health.
I’m looking for an answer
Miazek knows all too well how difficult it is to find answers. She tried to study the health effects of women working in coke ovens, but found only information from the 1960s.
“It’s 2024,” she said. “You would think we would have some research at least on the extremes of heat and how it affects women’s bodies.”
That’s why she recently traveled hundreds of kilometres to take part in an experiment at Brock University in St. Catharines, Ontario, to see how her body reacts to extreme heat, similar to what she experienced while working in coke ovens.
During the experiment, Miazek performed several tasks, once at a normal temperature of around 22 degrees Celsius while wearing regular clothes, and then again at around 40 degrees Celsius while wearing work clothes.
Cheung, who conducted the experiment, says it will help better understand the impact of heat on women working outdoors.
White Coat, Black Art follows Britnee Miazek, an apprentice metalworker who undergoes an experiment at Brock University to learn how her body copes with extreme temperatures.
Body temperature
As Dr. Amita Mahajan, an endocrinologist and professor at the Cumming School of Medicine at the University of Calgary, explains, a small area in the brain helps control body temperature.
Everyone has a hypothalamus, which helps maintain body temperature within a very narrow range, Mahajan says. It also helps regulate important functions such as blood pressure, sleep and, in women, reproductive function.
Mahajan says that when people like Miazek are exposed to high temperatures for weeks, they can increase the body’s basal metabolic rate — the amount of energy it needs while at rest in a mild environment.
This means the body needs more energy to function in the heat, and if we don’t take in more calories to meet those demands, Mahajan says, an energy mismatch will occur.
“And the hypothalamus — our control center — will sense that,” she told CBC Dose podcast.
Dose23:28What do we know about how a woman’s body copes with heat?
Experts know that men and women respond to heat differently, but we’re still learning how women respond to extreme temperatures. Dr. Amita Mahajan, an endocrinologist and clinical assistant professor at the University of Calgary, explains how extreme heat affects women’s bodies and the role hormones play in regulating their core temperature. For transcripts of The Dose, visit: lnk.to/dose-transcripts . Transcripts of each episode will be available the next business day. For more episodes of this podcast, click this link. [https://podcasts.apple.com/us/podcast/the-dose/id1498259551]
Research shows that in times of stress, the hypothalamus sometimes signals the body to stop ovulation and menstruation and instead focus on basic functions.
Mahajan notes that there isn’t much data on how the hypothalamus functions in women versus men in hot weather, aside from small studies of high-intensity exercise.
Females do better in hot, humid environments “because their bodies don’t send them signals to sweat as quickly as males do,” she said, adding that males, on the other hand, do better in hot, dry environments because they can sweat and lower their body temperature more quickly.
The role of estrogen and progesterone
Mahajan says scientists and medical experts know more about how body temperature changes during the menstrual cycle, which could affect how women feel heat.
She says high levels of estrogen — the dominant hormone in the first half of a woman’s cycle — causes body temperature to remain low.
In the second half of the cycle, lower estrogen levels and higher progesterone levels can cause a 0.4 to 0.8-degree rise in body temperature. The rise in progesterone during this phase of the cycle can mean that a woman “may subjectively feel a little warmer,” Mahajan says.
“It’s really important to listen to your body and understand that you may not feel the same in the second half of your cycle,” she said.
Pregnancy
Studies have shown that that pregnant women are more susceptible to intense changes in body temperature caused by larger body surface area, increased blood flow and basal metabolic rate.
“They need to be aware that the heat can affect them more quickly and worse than it did before pregnancy,” Mahajan said.
She notes that women who are expecting a baby may also notice higher body temperatures during the first trimester, when progesterone levels are higher.
In the second and third trimesters of pregnancy, when estrogen levels are high, body temperature is lower and it gets rid of heat more efficiently, which likely protects the fetus, Mahajan says.
Pregnant women are also more at risk of dehydration, which is why it is recommended to drink 2.5 to 3 liters of water a day.
Perimenopause and beyond
Temperature changes can occur throughout a woman’s life, including perimenopause and menopause. The hot flashes that many women experience during this time are due to fluctuations in estrogen.
The sweat threshold also changes during this time. In people who are not going through perimenopause, sweating begins when body temperature rises by 0.4 to 0.5 degrees.
For perimenopausal or menopausal women, just a 0.1 to 0.2 degree rise in body temperature is enough to cause them to sweat, Mahajan says.
She recommends that women in perimenopause or menopause stay cool by:
- Avoid prolonged exposure to heat
- Drink plenty of water
- Avoid spicy foods, caffeine and alcohol
Dr. Jerilynn Prior, an endocrinologist and professor at the University of British Columbia, advises paying attention to the signs of heat stress and drinking salty fluids if you work in a hot environment.
“Pay attention to your body. Is your heart beating too fast? That’s a big sign that you need to get somewhere cooler,” she said. “You need to drink more and move less.”
I’m still looking for an answer
In Miazek’s case, the experiment she participated in showed that working in higher temperatures caused her heart to beat faster, her sweating increased and her skin temperature rose.
Although she cannot clearly explain why she has not had a period for several months, she is happy to take part in research on women’s response to heat.
“It’s not about who has it worse. It’s literally about the differences and how it affects men’s and women’s bodies differently.”
This story is part of our Overheated series, a collaboration between What on Earth, Quirks & Quarks, and White Coat, Black Art, examining how heat is affecting our health, our cities, and our ecosystems.
