At some point, we’ve all woken up shivering and clutching the duvet in the middle of the night due to the cold. This common phenomenon affects most people and is mainly due to internal factors rather than your surroundings. We consider the science behind why you might be reaching for those extra blankets come 3am and what you can do to combat feeling cold at night.

Related: How to Get Out of Bed When It’s Cold

Why do I get cold when I sleep?

You get cold when you sleep due to your body’s core temperature. This is usually 36°C to 39°C, however it drops a degree or two overnight. This is a natural response due to a lack of exposure to light and lets your body know it’s time to rest. According to Web MD, a drop of temperature allows you to have a good night’s sleep, which is often why exercising less than an hour before bed isn’t recommended, as it heats the body.

Come daytime, natural or artificial light sends signals to your brain’s hypothalamus which then alerts the body’s natural clock, the suprachiasmatic nucleus. This lets you know it’s time to wake up but also rises your body temperature back up for the day. 

What causes a person to be cold at night?

Although this drop of body temperature is often a helpful nudge towards the land of nod, there can sometimes be other feeling cold at night causes, mainly certain medical conditions. If you often find yourself shivering while your partner is having a good night’s rest, it could be due to the following health problems:

1. Anaemia

Anaemia is a very common condition and occurs when your body struggles to make sufficient red blood cells to carry oxygen throughout the body. This will result in regular fatigue, irregular heartbeats and often feeling cold.

Read more about anaemia here.

2. Hypothyroidism (Underactive thyroid)

This occurs when your thyroid (a gland at the base of your neck) struggles to generate or process the thyroid hormone. Feeling cold is a regular symptom of hypothyroidism. However, weight gain, thinning hair, and constipation are other things to look out for.

See more symptoms for hypothyroidism here.

3. A blood vessel disorder

If your main problem is cold hands at feet at night, then this could be due to blood flow. The cause of cold feet at night is sometimes due to clotting disorders, the blood vessels narrowing, or spasms of the arteries. If you feel this might be the cause, look out for tingling and throbbing in your arms and legs, or white or blue pigment of your fingers and toes.

Find out more here.

4. Diabetes

Finally, another potential cause for feeling cold at night could be diabetes. Although unlikely, the kidney damage from diabetes results in feeling cold all the time, nausea, shortness of breath and swelling of the hands and feet.

See more symptoms and the causes of diabetes here.

What kind of vitamin deficiency makes you cold?

A lack of vitamin B12 or iron might leave you feeling cold. B12 can be found in chicken, eggs and fish, whereas iron is best found in green vegetables, such as spinach, beans or broccoli. According to Health, a regular intake of these vitamins can help you stay warm but also prevent issues such as hypothyroidism and anaemia. Dr Holly Phillips, author of The Exhaustion Breakthrough, says “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”.

How can I stop feeling cold at night?

If you’re concerned you may be affected by any of the above conditions, talk to your doctor about the best treatments. In general, it’s best to arm your immune system by taking regular vitamins and improving your lifestyle. Certain issues, like a blood vessel disorder, can be lessened by quitting smoking. Also, ensuring you are at a healthy weight will help you maintain a good temperature overnight.

If you are healthy but still struggling to sleep at night due to feeling cold, try adjusting your surroundings:

  • Set your heating to a timer which will turn off overnight
  • Consider wearing socks to bed
  • Have a warm bath before bed
  • Take a hot water bottle to bed with you

How do you stay warm when you’re feeling cold at night? Let us know in the comments.