The most romantic line of any movie is "I love that you get cold when it's 71 degrees out" from When Harry Met Sally. It beats all other declarations of love partly because it shows how well Harry knows Sally, but also because it brings much-deserved attention to the struggle women face of being *constantly* freezing. Seriously though, there are scientific reasons women are colder than men, and some of them are pretty weird.
Many an experiment has proven that it's not in your head; women actually do feel colder more often than men, though you likely know that from your everyday life. (I'm wrapped in a blanket as I write this.) These findings can't speak for the experience of every person on the planet, of course; some men run cold and some women run hot, especially in different phases of their life like during pregnancy or menopause. But in general, women are likely to be chillier than their male counterparts, and it's all to do with your very bodily make up.
So read on to find out some of the weirdest reasons you're always fighting with your partner about how many blankets should be in your bed, and consider investing in thermal pajamas.
1. Women typically have fewer muscles than men
Clearly, there are plenty of women who are more muscular than men, but generally, "Women have more body fat and less muscle than men" because women have more organs to protect, including the uterus, as Medical Express explained. And although this fat protects the organs, "it also restricts blood flow to the extremities," offering one reason you might find yourself with frigid fingers and toes more often than the men in your life.
2. Women have less blood than men...
Again, there are exceptions to this rule, but in general, women have lower blood volumes than men, as evidenced by a study published in The Faseb Journal. As Informed Health explains, blood "makes sure that the right body temperature is maintained. This is done both through blood plasma, which can absorb or give off heat, as well as through the speed at which the blood is flowing." Since women start off with less blood, their bodies can maintain less heat, leading you to feel chillier.
3. ... and female hormones make the blood you do have run slower
Even worse, the blood you do have doesn't move as quickly as men's does because of estrogen. As Hannah Devlin reported to The Guardian, estrogen makes blood slightly thicker, "reducing the flow to capillaries that supply the body’s extremities," and less blood in the extremities make you colder. Aurora Healthcare said that female bodies are designed to keep the reproductive system warm, so at least your uterus will be nice and toasty while your hands feel like they're gonna freeze off.
4. Women have a higher base temperature
A study conducted by JAMA Network found that women have a slightly higher base temperature than men, which in turn makes you more sensitive to external temperatures. Think about when you jump in freezing water after standing in the heat; your body feels even colder than it would have because you were so warm before. So although you're technically warmer than men, you'll feel colder than them. (Weird, I know.)
5. Your birth control isn't helping either
Hormonal birth control has a myriad of side effects, but a lesser known impact is the way it can change your body temperature. A study published in Pub Med found that hormonal birth control can increase your inner body temperature because it alters the levels of estrogen and progesterone in your system, making you even more sensitive to external temperature changes.
6. Women have slower metabolic rates than men
Ever noticed the men in your life seem to be able to lose weight with a lot less effort than you? It's likely because they actually have a higher metabolism than you, which also explains why they're toasty warm when you're freakin' freezing.
As I mentioned, men usually have more muscle than women, and their bodies thus work harder to burn fat, increasing their metabolisms. Livestrong explained, "while a person with a slow metabolism might have a lower body temperature, someone with a high metabolism will run warmer." So not only are men able to lose weight more quickly, they're also not going to be cold after that post-workout shower. (I have never resented my body more.)
7. Thermostats are usually set for men's comfort
Despite these established differences between male and female body's base temperatures, public spaces are often set up to accommodate men instead of women. A study published in Nature Climate Change reports that "Indoor climate regulations are based on an empirical thermal comfort model that was developed in the 1960s... Standard values for one of its primary variables — metabolic rate — are based on an average male" rates only. It's likely the temperature at your office is set for the men's comfort rather than women's, explaining why you keep three sweaters and a snuggie at your desk at all times.
A myriad of things can cause women to feel colder than men, and usually it's nothing to worry about. But if you notice you're always cold, have trouble feeling your hands and feet, or suddenly become more sensitive to temperature, it's best to check in with a doctor to make sure nothing is wrong. Stay warm, sisters.