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How longevity and sleep are connected

May 29, 2020 | Posted by Julia Herni
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It’s no secret that quality sleep is extremely important for your overall health. In fact, quality sleep has the ability to boost longevity. Matthew Walker, sleep expert, and neuroscientist, wrote in his book ‘Why We Sleep’: “The shorter you sleep, the shorter your lifespan”. And he’s not wrong. Several studies prove that insufficient sleep can shorten human longevity. But what Walker doesn’t mention is that oversleeping can also shorten your lifespan. Learn more about the impact of short and long-duration sleep on longevity. 

What does sleep deprivation do to your body?

Your body needs sleep. Sleep doesn’t just help you feel less tired, it boosts your mental and psychical health, improves your immune system, repairs your body, renews the brain, and more. A 2018 study proves just how important sleep is: it shows that insufficient sleep (short-duration sleep of <6 hours per night) causes all kinds of physical and mental dysfunction, such as obesity, weakened immunity, and diabetes. This image below highlights eleven effects of insufficient sleep.


Image: Effects of insufficient sleep. Source: Healthline

Yes, you can sleep too much

While insufficient sleep can lead to health problems, so can too much sleep. Oversleeping (long-duration sleep of >9 hours per night) is linked to several health problems. Research shows that oversleeping can cause the same effects as insufficient sleep, meaning an increased risk of obesity, weakened immunity, and diabetes.

For some people, oversleeping is actually a medical disorder. It’s called hypersomnia, or ‘long sleeping’. The disorder is characterized by the body’s tendency to remain asleep for longer periods of time: people with hypersomnia need 10 - 12 hours of sleep each night to feel good. The main symptom is constant tiredness. If you’re reading this and you’re thinking ‘oh god, I have hypersomnia!’, don’t worry. That is very unlikely. The condition affects about 5 percent of people.

There are two types of hypersomnia: primary and secondary. Primary hypersomnia occurs with no medical issues and is caused by circadian rhythm disorders or brain abnormalities. Secondary hypersomnia is due to medical conditions. These can include sleep issues (insomnia, sleep apnea) or diseases (Parkinson’s disease). In short, people with conditions that make them feel tired during the day are most at risk for hypersomnia. People who are overweight, drink regularly, or smoke a lot are also more at risk of developing hypersomnia.

You can’t self-diagnose hypersomnia. It’s quite a challenging condition to diagnose since there are a lot of steps in the diagnosing process. Doctors will consider a hypersomnia diagnosis if a person has had symptoms for over 3 months and if the symptoms significantly impacted the person’s life. The diagnosing process also involves excluding other causes of daytime sleepiness, such as insomnia and sleep apnea. Eventually, you might have to go through several tests. Some of the tests may include:

  • Keeping a sleep diary to keep track of sleeping patterns
  • Taking monitored naps during the day to measure the type of sleep that’s being experienced
  • Several sleep tests to determine the cause of sleep problems (polysomnography)

Hypersomnia isn’t the only factor that can cause oversleeping. Other brain and medical conditions can also result in excessive sleeping. For example, people with depression are more likely to oversleep than those who don’t have it. Sleep doctor Michael Breus says that an estimated 40% of people with depression sleep too much. A 2018 study even found that about ⅓ of people who were diagnosed with depression had both hypersomnia and insomnia. 

Obstructive sleep apnea is another condition that can cause people to start oversleeping. People with sleep apnea briefly stop breathing during sleep. This can occur repeatedly throughout the night, causing frequent awakenings. This negatively affects your sleep quality, leading to extended hours in bed to get some more sleep.

There’s one exception when oversleeping is actually beneficial for your body: sleeping more than usual when you’re sick is highly recommended. Sleep gives the body time to fight illness. It boosts your immune system to kill virally infected cells and improves the immune system’s response time. So don’t worry if you find yourself feeling more sleepy when you’re sick. It’s just your body saying it needs more rest to heal. If you’re still feeling very tired after your illness got better, it may be a good idea to visit a doctor.

Your doctor can prescribe various drugs to treat excessive sleepiness. However, those drugs won’t be a substitute for sleep. Here are some tips you can follow to cope with daytime sleepiness that are within your own control:

  • Stick to a consistent sleep schedule to promote a healthy sleeping routine
  • Limit alcohol to improve sleep patterns and sleep quality
  • Take 20-30 minute naps to restore alertness and enhance performance 

The effects of sleep on your lifespan 

Considering the dangers of short-duration and long-duration sleep, it’s not surprising that it can cause a lower life expectancy. A study conducted by Dr. Francesco Cappuccio shows how not getting the recommended amount of sleep (7-9 hours) can result in early death. 

The researchers did many studies in 27 cohorts (groups). The studies included 1,382,999 male and female participants. All studies assessed sleep duration by questionnaire and all assessed the outcome though death certification. There were 112,566 deaths during follow-up across all studies. The researchers found that <6-hour sleep was associated with a 12% increased risk of death. Even more shocking, >9-hour sleep was associated with a 30% increased risk of death. The outcome of this research proves that short-duration sleep and especially long-duration sleep significantly shorter your lifespan. 

Another research proves this statement. The graph below shows the outcome of three studies: a U-shaped curve, showing that progressively shorter or longer sleep duration is associated with greater mortality.

graph mortatlity
Image: Shorter or longer sleep duration is associated with greater mortality. Source: NCBI

How long should you sleep for longevity?

The recommended amount of sleep is 7-9 hours per night. However, sleep requirements vary slightly from person to person. Children and adolescents need more sleep, while older adults may require less. 

Table of recommended sleep time

The National Sleep Foundation says that apart from following the sleep time recommendations, it’s also very important to pay attention to your own individual needs by assessing how you feel on different amounts of sleep. These are some of the questions that the National Sleep Foundation recommends you to ask yourself:

  • Are you productive, healthy, and happy on seven hours of sleep? 
  • Are you experiencing sleep problems?
  • Do you depend on caffeine to get you through the day?

Summary

As we’ve seen, getting consistent, quality sleep is extremely important for longevity. Try to get the recommended amount of sleep every night to avoid health problems and increase your lifespan. We recommend tracking your sleep to be fully aware of your sleep habits. The Pod makes this very easy for you: the Active Grid Tech cover includes sensors that track your biometrics, such as sleep time, heart rate, and more.