Studies show that using a 6-8 kg heavy blanket can significantly improve sleep quality and alleviate symptoms of insomnia, anxiety, and depression. This discovery not only highlights the potential mental health benefits of heavy blankets but also explains the science behind “struggling to get up” during winter.
The sleep effect of heavy blankets
According to a study by the Karolinska Institute in Sweden, covering with a heavy blanket weighing 6-8 kg for just one month can not only significantly improve sleep quality, but also relieve anxiety and depression. The study was published in the Journal of Clinical Sleep Medicine.
As one of the most common mental illnesses, 30%-48% of adults have symptoms of insomnia, and another 6% meet the diagnostic criteria for insomnia. Especially among patients with mental illness, insomnia occurs more frequently-70% of patients with bipolar disorder and 60% of patients with anxiety and depression are deeply troubled by insomnia.
In this study, a total of 120 patients with insomnia for more than 2 months and any of the following mental illnesses including: major depression, bipolar disorder, anxiety disorder or ADHD were included. Participants were randomly assigned to two groups in a 1:1 ratio, one group covered with a heavy blanket, 6-8 kg (when participants felt that 8 kg was too heavy, they could be replaced with a 6 kg blanket), and one group covered with a light blanket weighing 1.5 kg as a control group.
The experiment showed that after using heavy blankets for 4 weeks, 59.4% of insomnia patients had improved insomnia and 42.2% had complete remission. In contrast, the light blanket group had only a 5.4% improvement rate and a complete remission rate of only 3.6%.
Figure 1: Changes in the insomnia severity index and insomnia improvement efficiency of the two groups of participants before and after the experiment, orange-heavy blanket group, blue-control group
Not only that, compared with the control group, the daytime fatigue, anxiety, and depression symptoms of participants using heavy blankets were reduced.
After the 4-week experiment, 112 participants continued to participate in the one-year heavy blanket use experiment. After one year, the effective rate of insomnia improvement for all participants was 92%, and the complete remission rate was 78%.
Figure 2: Changes in fatigue index and sleep maintenance before and after the experiment of the two groups of participants, and changes in daytime activities before and after the use of heavy blankets
The study found that heavy blankets not only improve sleep, but also improve daytime concentration, reduce fatigue, and relieve symptoms such as anxiety and depression. This shows that heavy quilts have significant benefits for sleep quality and mental health.
How do heavy quilts improve sleep?
Another study by the Swedish Brain Research Foundation revealed the potential mechanism by which heavy quilts improve sleep. The study included 26 healthy adults and compared the sleep effects of heavy quilts (about 12.2% of body weight) and light quilts (about 2.4% of body weight).
By collecting participants' saliva and testing the levels of melatonin, α-amylase, cortisol, and oxytocin, researchers can analyze the effects of quilt weight on multiple hormones and find out the "culprit" in the process of quilts improving sleep.
Experimental design (2 stages)
The Karolinska Sleepiness Scale (KSS) showed that the KSS score of a thick quilt was 0.2±0.2 points higher than that of a light blanket, and the closer to bedtime, the higher the KSS score, that is, the higher the sleepiness. However, the difference between the two groups was not significant.
When covered with a thick quilt, the increase in melatonin concentration in participants' saliva was greater. Covering with a heavy quilt can increase the participants' salivary melatonin concentration by an average of about 6.6±0.7pg/mL between 22:00-23:00 (one hour before bedtime), which is a significant increase of 32% compared to covering with a lighter quilt.
Melatonin is a hormone secreted by the pineal gland and is closely related to sleep. Studies have shown that the pressure signal generated by a heavy quilt on the skin is transmitted to the solitary nucleus of the brain through neural pathways, and further acts on the paraventricular nucleus of the hypothalamus, thereby enhancing inner peace, reducing stress, and promoting the secretion of melatonin by the pineal gland. This physiological mechanism provides a scientific basis for heavy quilts to improve sleep.
Conclusion
The researchers believe that the "pressure" brought by heavy quilts activates the skin sensory afferent nerves and transmits this feeling to the solitary nucleus (NTS) in the brain through the spinal cord. After receiving the "pressure" signal, the solitary nucleus further projects it to the paraventricular nucleus (PVH) of the hypothalamus. By stimulating the paraventricular nucleus, people's inner peace and happiness can be enhanced, and the feelings of fear, stress and pain can be reduced. In addition, these neurons are also connected to the pineal gland, which in turn affects the release of melatonin.
The significant therapeutic effect of heavy quilts on insomnia patients, especially those with mental illness, shows that it is not only a comfortable choice, but also a part of auxiliary treatment. These research results are not only instructive for insomnia treatment, but also remind us to pay attention to the impact of the environment and objects in daily life on health.