Feeling chilly when the AC is blasting is one thing. But if you’re always shivering, or your hands and feet feel like blocks of ice while everyone else nearby says the temperature feels toasty, then it’s time to investigate. It’s common for women to report feeling cold, partly as a result of physiology and also a greater susceptibility to conditions that can contribute to coldness, says Holly Phillips, MD, medical contributor for CBS2 News and author of The Exhaustion Breakthrough. This checklist of 10 reasons your internal thermostat is out of whack can help you get a handle on why you’re chronically freezing your butt off.
Reasons You Feel Cold All Time
You’re too thin
Low body weight—defined as a BMI hovering around 18.5 or under—can chill you out for a couple of reasons. First, when you’re underweight, you lack an adequate level of body fat to insulate you from cold temperatures, explains Maggie Moon, RD, a Los Angeles–based nutritionist. The other thing is, to maintain that low BMI, you have to reduce your food intake so you likely aren’t eating very much at all. Skimping on calories puts the brakes on your metabolism, so you don’t create enough body heat. Consider putting on a few pounds by loading up on whole, healthy foods that contain lots of protein, fat, and complex carbohydrates.
Add cold intolerance to the long list of health issues you can blame on the butterfly-shaped gland in your neck. “Always being cold is a telltale sign of hypothyroidism, which means your thyroid doesn’t secrete enough thyroid hormone,” says Dr. Phillips. Without the right level of this hormone, your metabolism slows, preventing your body’s engine from producing adequate heat. Other signs of hypothyroidism are thinning hair, dry skin, and fatigue.
Approximately 4.5% of Americans have this condition, and rates are higher in women who have recently been pregnant or are over age 60. If you suspect a thyroid problem, see your doctor, who can confirm the diagnosis with a blood test and get your thyroid out of the slow lane with prescription meds.
You don’t get enough iron
Low iron levels are one of the most common reasons for chronic coldness. Here’s why: Iron is a key mineral that helps your red blood cells carry oxygen throughout your body, bringing heat and other nutrients to every cell in your system, explains Dr. Phillips. Without enough iron, red blood cells can’t effectively do their job, and you shiver.
Iron is also crucial because a deficiency can make your thyroid lethargic, leading to hypothyroidism, which further leaves you freezing, says Moon. Iron supplements can help, but the best way to boost your iron intake is through healthy food: meat, eggs, leafy greens like spinach, and seafood are the best options, says Moon.
You don’t get enough sleep
“Sleep deprivation can wreck havoc on your nervous system, throwing off regulatory mechanisms in the brain that affect body temperature,” says Dr. Phillips. It’s not clear why this happens; studies suggest that in response to the stress of not getting quality snooze time, there’s a reduction in activity in the hypothalamus, the control panel of the brain where body temperature is regulated. A study from the European Journal of Applied Physiology appears to back this up: researchers documented a drop in body temperature in 20 sleep-deprived young adults. Metabolism may be a culprit here as well. When you’re fatigued from a restless night, your metabolism works at a more sluggish pace, says Dr. Phillips, producing less heat and slower circulation.
“Up to 60% of the adult human body is water, and water helps regulate body temperature,” says Moon. “If you’re adequately hydrated, water will trap heat and release it slowly, keeping your body temperature in a comfortable zone. With less water, your body is more sensitive to extreme temperatures.” Water warms you up another way as well. It helps power your metabolism, and a sluggish metabolism translates into less overall body heat. Aim for the requisite eight glasses a day at a minimum, recommends Moon, but always drink more before and after workouts.
You’re a woman
Find yourself in a constant battle with your spouse or male officemates for control of the thermostat? Turns out that feeling cold really is a gendered condition. “In general, women are better at conserving heat than men,” says Dr. Rohr. “In order to do this, women’s bodies are programmed to maintain blood flow to vital organs such as the brain and heart.” This directs blood flow toward these organs and away from less vital organs like hands and feet, says Dr. Rohr, which leaves these body parts chronically cold. Science bears this out: a University of Utah study found that though women had a slightly higher core body temperature than men, their hands came in at an average of 2.8 degrees cooler.