The key points

• Keep your bedroom cool during the day and air it out briefly in the evening or early morning to create pleasant sleeping conditions.

• Choose light, breathable sleepwear such as our DEEPSLEEPWEAR with COOLING effect, which wicks away heat and keeps the skin pleasantly dry.

• Support your sleep with small evening routines: a lukewarm shower, light meals and sufficient fluids promote relaxation and restful sleep – even on hot summer nights.

Why can't I sleep when it's hot?

When temperatures rise, sleep quality often suffers – and there's a very natural reason for this: our bodies need to lower their core temperature slightly in order to switch to sleep mode. In the summer heat, this is difficult to achieve, which delays falling asleep and makes sleep more restless.

Sleep researcher Christine Blume from the University of Basel explains:

‘Nights when the temperature doesn't drop below 20 degrees are uncomfortable. Studies have found that it takes longer to fall asleep, you wake up more often and sleep less deeply.’ – Christine Blume, SRF News

The REM and deep sleep phases – the phases in which the body and mind regenerate – are particularly affected. People who sleep in the heat wake up more often, sweat more and often feel exhausted the next morning, even though the night was long enough.

Tip: The ideal sleeping temperature is between 16 and 20°C. Anything above that can disrupt sleep architecture – the very structure that ensures restful nights.

What really helps against heat in the bedroom?

What really helps against heat in the bedroom starts long before bedtime: if the room is protected from sunlight during the day – for example, by closed shutters, curtains or reflective blinds – it heats up significantly less. In the evening and early morning, it is worth ventilating the room to let in cooler air, while a fan ensures pleasant air circulation. The sleeping environment itself also plays an important role: light bed linen and nightwear made of breathable natural fibres such as cotton, Tencel™ or linen promote heat dissipation from the body and prevent heat build-up. A lukewarm shower before bed also supports natural thermoregulation because it helps the skin to release heat more effectively. Sleep hygiene experts also recommend keeping the room temperature between 16 and 20 °C if possible, as above this range it becomes increasingly difficult for the body to switch to restful sleep mode.

What is the best clothing to wear in hot weather?

In summer heat, the right sleepwear is crucial – this is where our DEEPSLEEPWEAR collection with COOLING effect comes in. The lightweight pyjamas and nightgowns are made from breathable natural fibres such as cotton and Tencel™ and, thanks to innovative COOLING technology, provide an immediately noticeable cooling sensation on the skin. The loose fit allows for maximum air circulation, while the material absorbs moisture, dissipates heat and supports the body's natural thermoregulation. DEEPSLEEPWEAR prevents excessive sweating, keeps the skin pleasantly dry and ensures that you can fall asleep refreshed and sleep deeply even on hot summer nights.

Should you sleep with the window open when it's hot?

Whether you should sleep with the window open when it's hot depends mainly on the outside temperature. If it's cooler outside than in the bedroom, fresh air ensures a more pleasant room temperature and supports the body's natural heat dissipation. However, if the outside temperature rises above the inside temperature, an open window can let the heat in and disturb your sleep. It is particularly effective to ventilate briefly in the evening or at night when it cools down outside and to keep windows and curtains closed during the day to prevent the room from heating up. This keeps the bedroom at a comfortable temperature without compromising air quality.

Which drinks or foods promote good sleep in hot weather?

Even in hot weather, the right diet can have a positive effect on sleep. Light, water-rich foods such as cucumbers, melons or berries provide fluids without putting additional strain on the body. Lukewarm or slightly chilled drinks such as herbal teas (e.g. chamomile or lime blossom) or water are also helpful – they support hydration without overstimulating the circulation. Heavy meals, sugary snacks or drinks with a high caffeine content should be avoided shortly before bedtime, as they can stimulate the metabolism and increase body temperature. A small portion of easily digestible protein, such as yoghurt or quark, can also promote sleep without weighing you down.

Conclusion

Heat can severely impair sleep, but with targeted measures, the night can be made much more restful. It is important to keep the bedroom cool during the day, to ventilate it in the evening and early morning, and to use light, breathable bed linen and sleepwear. Our DEEPSLEEPWEAR with COOLING effect is particularly helpful here, as it wicks away moisture, ensures pleasant air circulation and supports the body's natural thermoregulation. In addition, lukewarm showers, light meals and sufficient fluids have a calming effect on the circulation. This maintains deep and REM sleep phases, making even warm summer nights restful. With these simple adjustments, sleep becomes much more relaxed despite the heat.