There are a few reasons your feet could be chilly, the first being the most obvious: Are you wearing socks? Maybe your feet are cold because you’re not covering them and are walking on a cold floor.

OK then — now that we’ve ruled out the most obvious reason your feet may be chilly, let’s explore some more, less obvious explanations:

One very common reason people experience cold feet is poor circulation, meaning that not enough blood is getting to your feet (or in some cases, your hands as well) to keep them warm. This can be caused by a sedentary lifestyle (think office job) and can often be remedied by walking around for a bit each day. Poor circulation can also be the cause of blood clots and can lead to other health issues as well. Be sure to check with your doctor if you think this is the problem.

Another common cause of cold feet is an underactive thyroid. More common in women than in men, hypothyroidism can cause cold feet and hands, fatigue, hair loss and weight gain, among other symptoms. If you do have a thyroid issue and are taking medication for it, but still experiencing cold hands and feet, you could have Raynaud’s syndrome. Raynaud’s syndrome is characterized by a loss of blood flow to the hands and feet caused by spasms in the blood vessels.

Some people with cold feet can have peripheral neuropathy, in which someone may experience a cold feeling in the hands and feet without the hands or feet actually being cold to the touch. Other symptoms can include numbness, tingling or a burning sensation in the extremities. Though this can be annoying in and of itself, peripheral neuropathy is a sign of underlying nerve damage, caused by diseases such as diabetes, exposure to toxins, infections, or vitamin deficiencies. If you suspect this may be the issue, tell your doctor right away, as waiting can allow more nerve damage to occur. Your doctor may perform several tests, including NCS (nerve conduction studies) to see how well messages from the brain are being carried to the peripheral nerves.

Incidentally, did you ever wonder where the expression “getting cold feet” comes from? “Cold feet” as an expression connotes loss of courage, such as when a performer gets cold feet right before he goes on stage to a thousand waiting fans (uh-oh) or a bride gets cold feet before her wedding day (double uh-oh). Linguists trace it back to either Italian playwright Ben Jonson in 1605 or German author Fritz Reuter in an 1862 novel. The earliest use of it in the English language dates back to writer Stephen Crane in his 1896 book, “Maggie: A Girl on the Streets” in which he writes, “I knew this was the way it would be. They got cold feet.”

No matter where the phrase comes from and no matter the underlying cause, cold feet can be a nuisance, and in some cases, a sign that something more serious is going on. Be sure to check with your doctor if you think this is the case. If not, go put on a warm pair of socks and stop Googling stuff late at night.