CURA Weighted Duvets Increase Melatonin Levels

A new study from Uppsala University shows that the use of a weighted duvet increases melatonin in healthy young adults at bedtime. Secretion of the hormone melatonin signals to the body that it's time to sleep, and this can help increase sleepiness.

In a previous study, researchers found that the pressure of a weighted duvet can activate special sensors in the skin and stimulate brain areas that influence the release of feel-good hormones. A more in-depth study of the correlation between weighted duvets and the production of melatonin and oxytocin has recently been carried out by – among others – Christian Benedict, Sweden's leading sleep researcher. The study is unique in that it is the first sleep study to be done on healthy, young people with no previous sleep problems. The fact that they also exhibited melatonin secretion is an exciting result! The results have been published in the Journal of Sleep Research and in this article you can read a short summary of the study.

What is a weighted duvet?

You have probably heard of weighted duvets. Maybe you’ve even tried one yourself. These extra heavy duvets or blankets that are said to have a calming and sleep-enhancing effect have become increasingly popular in shops and in our homes.

A weighted duvet is exactly what it sounds like – a duvet with more weight than a normal one. CURA of Sweden offers weighted duvets for improved sleep quality, and has since its launch in 2017 become the leading brand in weighted duvets and other sleep-related products for the bedroom. You can choose from several different types of weighted duvets, ensuring that you will find one that suits your specific needs. It’s best to start with a lesser weight and then gradually increase the weight of the duvet.

A study by sleep expert Christian Benedict

Studies have shown that using a duvet with additional weight can alleviate insomnia, but the mechanisms behind this phenomenon have not yet been  made clear. That's why a team of researchers, including sleep researcher Christian Benedict from Uppsala University, has enlisted the help of 26 healthy young men and women to investigate whether the use of CURA weighted duvets can increase the production of the hormones melatonin and oxytocin at bedtime. These hormones have a sedative effect, causing drowsiness and relief from stress. The study also investigated whether the use of a weighted duvet could reduce activity in the body's stress systems.

To investigate this, saliva was collected from participants while they were lying under a weighted duvet and a regular duvet, and then levels of melatonin, oxytocin, cortisol and sympathetic nervous system activity were measured to see if there were any differences.

How the study was conducted

The study is titled "A weighted duvet increases pre-sleep salivary concentrations of melatonin in young, healthy adults" and the results were published in early October 2022. The aim of the study was to investigate the influence of weight on the production of melatonin and oxytocin during bedtime in healthy young adults. As mentioned earlier, 26 people, 15 men and 11 women, of a young age and in good health were used to compare the difference between using a duvet that weighed about 12% of the person's total body weight, a so-called weighted duvet, and a regular duvet that weighed about 2.4 % of their total body weight.

The study involved subjects spending two nights in the laboratory, plus a so-called adaptation night to get used to the laboratory environment. They were also asked to use both a light duvet and a weighted duvet at home for a number of nights before the study was conducted. The volunteers were then given dinner, and sat in front of two light-emitting diodes at 300 lux throughout the evening (from between 19:00 to 21:00) in order for all the participants to have similar levels of melatonin. Melatonin is the hormone that tells the body it's time to sleep and is released at night. Between 9pm and 11pm, the lighting was dimmed to 5 lux, and the room was made dark between 11pm and 7am.

On one night, the test subjects slept with a light ordinary duvet and on the other night they slept with a weighted duvet from CURA of Sweden. Saliva was collected every 20 minutes between 10pm and 11pm to see the effects of the different duvets on melatonin, alpha-amylase, cortisol and oxytocin. Subjective fatigue was also monitored every 20 minutes between 10pm and 11pm and the next morning between 7am and 8am. This was done using the Karolinska Sleepiness Scale, which is a self-assessment questionnaire that measures sleep difficulties.

Demonstrated increase in melatonin at bedtime

What could be deduced from the study was that there were no major differences in subjective fatigue or total sleep time between a light duvet and a weighted duvet. However, what could be seen by collecting the saliva of the test subjects when they were lying under a weighted duvet or a light duvet was a difference in the melatonin level at bedtime itself - that is, the time from when the test subject went to bed (10pm) to when the lights went out (11pm). During this hour, salivary melatonin increased by 32%, which is incredibly exciting because melatonin is a hormone that makes you sleepy.

The secretion of melatonin is probably the body's main mechanism for making it tired and ready to fall asleep, but whether the observed increase in melatonin is what contributes to the sleep-enhancing and calming effects of weighted duvets reported in previous studies cannot be clarified. No differences in oxytocin, cortisol and sympathetic nervous system activity were observed with the use of a lightweight or a weighted duvet.

Hope for more sleep studies in the future

This study simply cannot identify the underlying mechanism for the observed stimulatory effects of the weighted duvet on melatonin. However, one explanation looked at earlier may be that the pressure from gravity activates cutaneous sensory afferents and transports sensory information via the spinal cord to the solitary nucleus in the brainstem. This area of the brainstem has projection pathways to the paraventricular nucleus of the hypothalamus, which is a brain area that hosts the parvocellular oxytocin neurons. Through their ability to influence other brain networks, parvocellular oxytocin neurons can promote calm and well-being and reduce fear, pain and stress. In addition, they are linked to the pineal gland and may thus affect the release of melatonin, which may explain the significant increase in salivary melatonin in weighted duvet users.

Although the study did not show any difference during sleep itself, this result does indicate that weighted duvets have a melatonin-enhancing effect at bedtime, which in turn may have a positive effect on overall sleep and time spent in bed. The study may simply help explain why some people experience improved sleep with weighted duvets, but a larger study is needed to establish the relationship with certainty. This study was conducted over a few nights with a relatively small number of subjects and shows only the immediate effect of the weighted duvet, but by studying subjects on a nightly basis over several weeks or months it would be possible to see if the melatonin increase is sustained over a longer period of time. Hopefully this is a study we will be able to take advantage of in the future!

Sleep well with weighted duvets from CURA of Sweden

In the meantime, if you experience anxiety or stress when going to bed, it might be worth trying our weighted duvets to see if they can have a positive impact on your night's sleep. You decide how much you want it to weigh and what materials it should be made of to suit your body and your preferences. The weighted duvets are available in weights from 3kg up to 16kg, and it's usually an advantage to start low and then increase the weight as you go to see what suits you.

Read more about the study for more detailed results on the increase in melatonin and the impact on oxytocin, cortisol and sympathetic nervous system activity. We hope this article has given you a better idea of how weighted duvets work and what effects they can have on the body in terms of sleep, stress and anxiety reduction.

Other sources:

https://www.1177.se/Stockholm/liv--halsa/sa-fungerar-kroppen/hormonsystemet/

https://onlinelibrary.wiley.com/doi/10.1111/jsr.13743