We all know one – someone who’s constantly feeling too hot or too cold at home or in the office. Why is it that when everyone else is shivering, they’re comfortable in a T-shirt? Or when it’s a temperate summer day, they’ll be cozy in a sweatshirt and jeans? Sometimes the answer is that you’re situated in a drafty area or poorly insulated home. But if you’re consistently fighting over the thermostat, here are some surprising possible explanations.

You Have Poor Circulation

Do you have (literal) cold feet? A common cause of cold feet or hands is poor circulation. When your blood doesn’t flow as readily to your limbs and extremities, it can cause them to feel cold, even if the core of your body is at a comfortable temperature. If you always have chilly hands and feet, you might want to consider checking with your doctor to see if you can improve your circulation.

Don’t worry too much, though – poor circulation is a common issue and usually not indicative of a larger medical problem. It can be easily improved by wearing gloves and thicker socks, or by taking short exercise breaks to encourage blood flow.

You’re Tired

Everybody knows the health and beauty benefits of getting enough sleep, but feeling cold may be a surprising cost of not getting enough rest. Many people report feeling consistently more cold when tired, and science may support those reports. There is evidence that when you don’t get enough sleep, your metabolism slows down, lowering your body temperature. In addition to feeling sluggish, you may also feel colder than your well-rested peers. Make sure you’re getting around 8 hours of restful sleep a night to keep yourself alert and comfortable.

You Drink Too Much Coffee

If you’re feeling hot, it could be that you’re over-caffeinated. Drinking coffee to combat the morning grogginess could warm you up a little too much. Over-consumption of caffeine could lead to dehydration or an increase in body temperature. Feeling warm, having a raised heartbeat, and even breaking into a light sweat are signs you’re drinking too much coffee. If you’re consistently feeling like a tropical island of one, consider switching to decaf or skipping that third cup of joe.

You’re Stressed Out

Are you hot and bothered? Most people know that in high-stress situations, your fight-or-flight response can cause a physical reaction. But if you’re consistently feeling stressed out, it can cause your body temperature to rise and for you to feel too warm. The part of your brain that controls temperature regulation can become overwhelmed when you’re in a stressful situation, which means you’ll be feeling hot in addition to stressed. Try not to get too worked up – this too shall pass.

The moral of the story? Try to make sure you’re getting enough rest, drinking enough water, and not sitting still for hours at a time. If you’re still feeling cold or hot, consider checking in with your thermostat – or with your doctor.