By Dr. Roshini Raj

My hands and feet are constantly cold. I’ve heard people say that it’s from bad circulation, but that can’t be true, right? 

Actually, that’s not totally inaccurate. Your skin is kept at a comfortable temperature by your blood vessels, which distribute oxygen-rich blood throughout your body. When the mercury drops, sensory receptors in your skin alert your brain to constrict vessels. This allows smaller amounts of blood to your skin to conserve warmth in the trunk of your body, where all your organs are.

In some people, vasoconstriction, as this process is called, can be triggered by the slightest thermometer changes. And one study found that this type of reaction is more common in women, in part due to our fluctuating levels of estrogen, a hormone that plays a big role in regulating temperature. (So you’re not imagining it—you really are more sensitive to cold than your guy!)

A more severe cold sensitivity is a hallmark of Raynaud’s disease, in which extremities—usually just fingers and toes but sometimes also nose and ears—may turn white or blue and go numb. Depending on how bad your symptoms are, treatment may range from wearing extra gloves and socks to taking prescription meds that widen blood vessels.

Finally, cold hands may be a symptom of other conditions, such as hypothyroidism, lupus, or diabetes, or low levels of iron or a vitamin B12 deficiency. Your doctor can perform tests and prescribe the right medication, supplements or diet changes. But if cold hands are your only complaint, try warming them by staying hydrated and increasing your activity levels (get up from your desk at least every hour).

Health’s medical editor, Roshini Rajapaksa, MD, is assistant professor of medicine at the NYU School of Medicine.

Meet Dr. Raj at the Health Total Wellness Weekend at Canyon Ranch in May 2015. For details, go to Health.com/TotalWellness.

Originally published at Health.com