Warm or cool? Understanding your body's needs at night

Some people push the duvet away in the first few hours. Others never really warm up. These differences aren't trivial — they reveal how your body manages its own temperature regulation during the night.

The body and temperature

Falling asleep is linked to a drop in core body temperature. At the end of the day, the body starts redistributing its heat towards the extremities — hands and feet — to release it and lower its internal temperature. This process supports melatonin production and prepares the nervous system for rest.

During the night, this temperature keeps changing. It reaches its lowest point around 4 am, then gradually rises until you wake up. The environment you sleep in should support this natural movement — neither slowing it down nor disrupting it.

Those who run hot

Some people naturally tend to produce more body heat, or to release it poorly. This is often the case for people with a high metabolism, but also during certain hormonal phases — pregnancy, menstruation, perimenopause. The surrounding environment also plays a role: a poorly ventilated bedroom, synthetic bedding that doesn't breathe, or an overly enveloping memory foam mattress can make the feeling of heat worse.

The result shows up as frequent night-time awakenings, restless sleep, or tiredness on waking despite a satisfactory amount of sleep.

Those who feel cold

The opposite extreme exists too. Some people struggle to fall asleep because their extremities stay cold, a sign that the body has trouble redistributing heat effectively. Slower peripheral circulation, chronic stress, or simply a natural predisposition can be the cause.

For these profiles, the solution isn't necessarily to heat the bedroom more — which would upset the overall thermal balance — but rather to work on the comfort of the extremities: light socks, a hot-water bottle at the feet, bedding materials that are both soft and insulating.

The solutions

In both cases, the bedroom temperature should be between 16 and 19 degrees Celsius — a range that sleep research considers optimal for most profiles. But the room temperature is only part of the equation.

The materials in direct contact with the body have a considerable impact. Natural fibres — linen, organic cotton, fine merino wool — adapt to temperature changes: they absorb moisture when the body heats up and give back warmth when it cools down. This is what is known as thermo-regulating behaviour.

The surface of the pillow matters as much as the sheets, since it stays in contact with the neck and face all night. That's the principle behind the Olynne Fresh pillow, whose technical-fabric side continuously draws heat away from the body — so you no longer have to flip it over in the middle of the night.

Choosing your sheets, duvet or pillow according to your thermal profile is one of the most direct — and most underrated — ways to improve sleep quality. No need for a complex device. Just materials that work with the body rather than against it.