You’ve been hearing this for years: Eight hours of sleep is key to good health. However, new research suggests otherwise.
A recent study published in Aging in nature found that seven hours of sleep can really be the best. In their study, researchers evaluated sleep time in relation to cognitive function, brain structure, and mental health.
The researchers looked at sleep cycles, cognitive ability and mental health in nearly 500,000 adults, obtaining data from the UK Biobank, a large-scale collection of genetic and medical data. All participants were between 38 and 73 years old. (Sorry, Gen-Z, your sleep study will arrive.) The study was also based on participants’ answers to questions about their sleep and mental health habits, as well as cognitive tests and near-brain imaging. 40,000 participants as well.
In the study, the researchers found that too much or too little sleep negatively affected participants’ cognitive function (i.e., their memory and problem solving). Those who slept seven hours a night showed better brain function as well as better overall emotional well-being.
How sleep connects to your cognitive function
When it comes to sleeping, you prioritize quality over quantity. The researchers noted that the strength of a seven-hour night may lie in the lack of sleep interruptions. At seven o’clock, you can take advantage of the slow-wave sleep, also known as your deep sleep. According to the American Sleep Association, this type of sleep allows you to process and consolidate memories in your brain.
If you’ve ever spent the night or suffered from insomnia, this concept may resonate. The ramifications of your sleep deprivation state appear almost immediately. You may forget little things or just think. It’s not in your head. (Well, that’s right.) Without sleep, your brain doesn’t have a chance to consolidate critical memories. You didn’t give your brain the tools to do it.
Over time, sleep deprivation can have even greater consequences for your memory. A small study by the National Institutes of Health in 2018 found a higher presence of beta-amyloid, a protein associated with Alzheimer’s disease, in sleep-deprived participants.
Both studies call for more evidence to definitively establish causal links between sleep time and brain health. However, it is clear that your sleep plays a key role in the processing of your daily memory.
How sleep affects your mental health
According to the study, sleeping more than seven hours a night also caused an increase in symptoms related to anxiety and depression.
You’re probably familiar with the concept of waking up on the wrong side of the bed and feeling safe. A night of sleep deprivation can make you feel moody, angry, sad, or anxious. And the findings in the Aging in nature the study supports this change. The researchers found that participants who slept seven hours a night regularly had better mental health than participants who slept more or less seven hours.
How to get a good night’s sleep
We’ve all been there. If you’re wandering around all night, you may want to calm down with a sleep meditation or some relaxing yoga poses. Restorative yoga practices can help calm your nervous system and bring you to a more relaxed state. (Try the restorative yoga postures that Jonathan Van Ness uses to go back to sleep.)
If you’re just a night owl, someone who tends to go to bed later and seems to need less sleep, you may have a delayed sleep phase disorder (DSPD). If your circadian rhythms are off, this can make you go to bed late. A provider may prescribe melatonin supplements or light exposure therapy. Practice good sleep hygiene by avoiding caffeine or alcohol in the evening, moving the TV and work materials out of the room, and exercising in the morning instead of exercising at night.
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