Why Do I Get Cold at Night and How Can I Stop It?

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 problem is something that most of us have experienced and is mainly due to internal factors rather than our surroundings. Understanding these factors can help you take steps to stay warm and comfortable throughout the night.

Why am I waking up cold?

When you sleep, your core body temperature drops to align with your circadian rhythm, from 36.4-37.2 °C to about 1 °C lower. This might not seem like much, but it can sometimes make you feel chilly at night and even wake you up.

Getting cold at night is normal and signals to your brain that you are ready to sleep. Our core temperature continues to drop until about halfway through the sleep cycle, when it reaches its minimum. The timing of this can vary.

A 2001 sleep study categorised 172 men and women into sleep chronotypes—either “morning people” or “night owls” and they measured their nighttime temperatures. Morning people reached their lowest temperature after 3.5 hours, while night owls took longer at 6.01 hours.

By morning, natural light alerts your hypothalamus to wake you up by signalling the suprachiasmatic nucleus, which raises your core temperature. If you’re a night owl and reach your lowest temperature later, it may take longer to rise, explaining why you might struggle to get out of bed and feel less alert in the morning. Learn more about optimal body heat with our guide: what’s the best temperature for sleep?

Why being cold helps you sleep

Why we have evolved to become cold at night remains a mystery, though researchers believe it may be linked to various body cycles, including the functioning of major organs.

One reason is that the drop in temperature is connected to a decrease in metabolism, which is thought to be regulated by our circadian rhythm. Metabolic rate can drop as much as 15% in humans during sleep, signalling to our brains that it’s time to rest.

A lower body temperature at night also aids energy conservation. Having a time (such as sleep) where you use as little energy as possible would have been beneficial for our ancestors, who likely struggled to find enough food. Using minimal energy to maintain body heat allows more resources to be allocated to restorative processes throughout the night.

In line with our body’s natural processes, creating a cooler sleep environment can help you fall asleep faster. Allowing your body temperature to drop during the evening sends the signal to your brain that you’re ready to sleep. Exercising a few hours before bed or having a warm bath or shower before hitting the hay can also help facilitate a drop in body temperature and assist you in drifting off.

Other reasons you're waking up cold

Apart from your body naturally dropping in temperature at night, which often gives a helpful nudge towards the land of nod, there are other reasons why you might feel the chill more:

1. Inadequate bedding or clothing

You might feel cold at night if you’re not layered up enough, especially during the colder months. Some duvets, like those designed for summer, aren’t as effective at retaining heat. Choosing the right bedding for the colder weather and the appropriate sleepwear can make all the difference, helping you stay warm and cosy while you rest.

Learn more about what to wear to bed.

2. Room temperature

The temperature tends to drop during the night, so if you have the thermostat set quite low to begin with, your room could end up a little too chilly. This is more likely to happen if you sleep with the windows open or have poor insulation, which can lead to drafts. Aim for an optimum temperature between 16–20°C for a comfortable, full night’s sleep.

3. Hydration and diet

Both dehydration and low sugar levels can cause you to feel the cold. This is because your body doesn’t have enough energy to produce and retain heat. To stay hydrated ahead of bedtime, why not try one of our drinks to help you sleep?

4. Poor circulation

If you often get cold hands and feet, it’s likely due to poor circulation. This could be caused by a range of factors, such as anxiety, sitting or lying in one position for too long, or underlying conditions like a lack of iron. Speak to your doctor if you experience cold extremities to help get to the bottom of what’s causing you to wake up cold.

5. Stress or anxiety

Worrying about future plans or overthinking how your day went can impact your ability to fall asleep and affect your overall body temperature. Stress or anxiety can cause blood vessels to constrict, limiting blood flow and making you feel colder.

6. Medical conditions

Several other medical conditions can cause you to feel cold more often, especially when your core body temperature drops at night. These include:

Anaemia: A common condition where your body struggles to produce sufficient red blood cells to carry oxygen throughout the body. This can result in regular fatigue, irregular heartbeats, and often feeling cold.
Hypothyroidism: This occurs when your thyroid (a gland at the base of your neck) struggles to generate or process thyroid hormone. Feeling cold is a common symptom of hypothyroidism, along with weight gain, thinning hair, and constipation.
Blood vessel disorders: Clotting disorders cause blood vessels to narrow and can lead to spasms of the arteries, which may result in cold feet.
Diabetes: Kidney damage caused by diabetes can lead to feeling cold all the time, nausea, shortness of breath, and swelling in the hands and feet.

How does vitamin deficiency make you cold at night?

Various vitamin deficiencies can cause you to feel so cold at night that it becomes difficult to sleep. A lack of B12 and iron is typically the culprit, as deficiencies in these nutrients can lead to some of the issues mentioned above.

B12 can be found in chicken, eggs, and fish, while iron is best sourced from green vegetables such as spinach, beans, and broccoli. According to Health, regular intake of these nutrients can help you stay warm and prevent issues like 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.”

What might cause you to wake up shivering?

If you’re not just waking up cold but actually shivering, it could be a sign of underlying health conditions. These can include:

Menopause

Hormonal changes linked to menopause can cause chills at night. These can occur on their own or after a hot flush.

Infection

An immune reaction to an infection is often associated with fever but can also cause chills. These chills result from muscles quickly contracting and relaxing, and they often signal that a fever is coming.

If you’re feeling under the weather and it’s keeping you awake, learn ways to help you sleep when you have a cold and support your body’s recovery while you rest.

How can I stop feeling cold at night?

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

Set your heating on a timer so it turns off overnight.
Consider wearing socks to bed.
Have a warm bath before bed.
Take a hot water bottle to bed with you.

If you’re concerned that you may be affected by any of the above conditions, talk to your doctor about the best treatment options. In general, it’s a good idea to support your immune system by eating a balanced diet and improving your lifestyle. Adopting healthy habits and maintaining a healthy weight will also help support your body’s natural heat regulation at night.