Optimize Temperature and Light at Night with the Science of New Sleepwear Technology

By Dr. Dan Gartenberg

After examining thousands of people's sleep, I've discovered that one of the most effective things is to perfect a poor sleepers temperature and light environment. Temperature and light are some of the most important external cues, or zeitgebers, that tell our body when to fall asleep and when to be alert. 

The below sleep hacks are so effective because once you do them, they can positively impact every night of sleep for the rest of your life. I've seen the benefits myself, where after months of arguing with my spouse about the thermostat or lighting in the room,  I finally invested in a sleep mask and high quality Pajamas for both
men and women designed to address this problem.

By keeping the bedroom very cold and wearing layers, you can optimize the temperature in your sleep environment and sleep more deeply. But it gets much more sophisticated than this if you truly want to optimize your sleep. This is why I recently teamed up with Dagsmejan luxury PJs and developed a sleep program with them within the SleepSpace app. Read the below sleep solutions to learn more. 

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1. Keeping the best temperature for sleep

How to do it

What many might not be aware of is the massive impact temperature has on our sleep quality and sleep duration. In particular our deep sleep phases and our REM sleep is impacted by temperature fluctuations, as a result we spend less time in these phases. The result? A lower quality sleep that fails to give us the energy we want and need when we are awake.

Studies have shown that around 40% of people mention being too warm or too cold as the most disturbing factor preventing them from enjoying a great sleep. If we become too warm, and can't release that heat fast enough, we start to sweat. Sweating while sleeping is totally normal, we sweat on average one cup every night. However, with the wrong materials it can lead to uncomfortable wetness on our skin. 

Most couples run at different body temperatures for optimal sleep. And even if you sleep alone, it can be challenging to get the perfect temperature. Yet decreasing internal body temperature sends a cue to our alertness system that now it is time to fall asleep. Counterintuitively, increasing the temperature of your limbs (with special socks), decreases your internal body temperature. This signals to your body that it is time for sleep. But you can also easily be too hot with socks. That's why a good strategy for deeper sleep with sleepwear is to keep the room very cold (i.e. 60-68 degrees) and layer up with pajamas, socks, and multiple blankets. You won't regret it! Get $15 off all purchases of Dagsmejan with promo code sleepspace23 at checkout

Best temperature settings to improve sleep quality with Dagsmejan
Graph of the percentage of people who are too hot or too cold at night

2. Why what we wear matters

How to do it

To keep the best temperature for sleep we need to wear the right clothing at night. When choosing what pajamas to wear at night there are 4 factors to look for:

1) Temperature regulation: a breathable pajama is critical as this helps to release excess heat so that we don't overheat and start to sweat. We also don't want to become too cold however, as we then can start to shiver which also disturbs our sleep quality. Natural material tends to be more breathable than synthetics.

2) Moisture management: we all sweat but if our sleepwear gets damp or soaked we can easily get cold and start to shiver. A sweat wicking pajama helps to make sure that sweat is wicked away from the skin

3) Fit and comfort: as we move over 40 times every night in big and small movements we want to make sure that our sleepwear moves with it. So look for a comfort design. The most comfortable pajamas should be like a second skin.

4) Super soft touch: during the night the blood flow in our skin increases making us more sensitive to touch. Look for flat, ergonomic seams and a tagless design for a minimum of friction and rubbing at night.

3. Matching your individual physiological sleep needs

How to do it

Dagsmejan temperature regulating pajamas is developed to meet your personal sleep needs, regardless of if you are hot and cold at night, always overheat or tend to shiver and get cold. Using the finest natural fibres combined with the latest textile technologies, Dagsmejan is scientifically proven to help you to sleep better. Find your sleep solution:


Keep comfortably warm and never overheat with the stay warm collection. 4x more breathable than cotton this collection is as warming as other fabrics up to 50% heavier.

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Dagsmejan eye mask for complete comfort and pitch black bedroom environment

4. Ensure that your bedroom environment is pitch black

How to do it

Did you know that humans have receptors in their eyes that can detect different types of light even when your eyelids are closed? This is why it is extremely important to have a pitch back bedroom environment. Otherwise, these receptors in your eyes, called photoreceptors, send a signal to your brain to inhibit melatonin at a time when your brain should be producing more melatonin. One of the simplest hacks to solve for this is an eye mask. We recommend the Dagsmejan Sleep Mask  for a few reasons: 1) It completely blocks out light, 2) It dissipates heat well which is important for falling asleep, 3) It is made of a hypoallergenic material that ensures comfortable sleep. This solution is ideal for travel as well, since many hotel rooms have annoying lights from electronic devices and other sources. Other solutions for your home include getting blackout blinds and putting black tape or stickers over any electronics that emit light.   

Man keeping a clean bedroom in order to promote sleep hygiene

5. Keep your head cool for falling back asleep

How to do it

Another hack that goes along with this is cooling your head to help fall asleep since the core body temperature is related to the temperature of the head or torso. Having a cool pillow that isn't warmed by your body heat that you can swap in during the middle of the night can help with staying asleep in the middle of the night if you wake up. On the Ben Greenfield Life podcast we delve deep into how to optimize temperature to improve your sleep quality. 

woman trying to sleep