Why Sleep Is the Key to Living Longer

Today, at the age of 63, I find myself in peak health—physically, mentally, and energetically. A wide range of performance metrics and biomarker data bolster this belief. I’ve gotten here not by luck, but by effort and by prioritizing healthspan: the amount of time you spend in good health, free of disease. I'm on a personal mission to maintain this optimal health for the next decade, so that I can intercept the next generation of therapeutics under development that are promising to slow, stop, and even reverse aging.

Over the past decade, my primary focus has been to study the field of human longevity with an eye specifically toward healthspan. I've immersed myself in research and devoured publications in the realms of biotechnology, nutrition, exercise, sleep, and, most recently, artificial intelligence in service of health and longevity. I've interviewed top scientists on my Moonshots podcast and onstage during my longevity conferences. I’ve even launched XPRIZE Healthspan, where more than 440 teams are currently competing for $101 million to see what can most effectively turn back the ravages of aging. Finally, I hold in close company dozens of top scientists and physicians who work closely with me in the various companies I founded or co-founded.

People often ask me the very same question I’ve posed to these longevity luminaries for years: what can you do to live a longer, healthier life? The answer is so rich and varied that I’ve written a whole guidebook sharing the tools that I’m personally using today to maximize my own healthspan. The Longevity Guidebook includes how to exercise to build muscle and VO2 max, the advanced diagnostics available right now for preventative care, supplements and medications that optimize cellular and whole-body function, how to create and maintain a longevity mindset, and tailored approaches for women’s health. I’m grateful to draw on cutting-edge insights from my friends who are leading experts in the longevity sciences. 

One of the most important (and least appreciated) keys to extending your healthspan is a great night’s sleep. It rejuvenates the body, boosts cognitive function, and powers your immune system. It’s the foundation for your health and longevity.

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Sleep expert Matthew Walker, director of the Center for Human Sleep Science at the University of California, Berkeley and author of the excellent book Why We Sleep, says that sleep is the single most effective thing we can do to reset our mental and physical health each day. There is a direct relationship between how well you sleep and how long you live, and almost nobody can get away with fewer than six hours of sleep a night without harming their health.

For most people, regularly getting eight hours of sleep boosts memory retention, enhances concentration, augments creativity, stabilizes emotions, strengthens the immune system, enhances athletic performance, and staves off deadly ailments like cancers and heart disease.

Still not convinced?  Here are three powerful examples:

1. The difference between getting a good night’s sleep and a bad one is a decrease from 100% to 60% in the brain's ability to retain new facts. That’s the difference, as Walker puts it, between “acing an exam and failing it miserably.”

2. Going twenty-four hours without sleep is like having a blood alcohol concentration of 0.10%, above the legal limit for driving in most places.

3. A sleepless night with only four hours of sleep resulted in a 70% reduction in the activity of your natural killer cells (which combat infections and cancer). Remarkably, the activity of natural killer cells returns to baseline levels after one night of normal sleep.

Sleep doesn’t get the respect it deserves. It’s often the first thing people sacrifice to make time for almost anything else, whether leisure or work. But the popular belief that “you can sleep when you’re dead” is fundamentally damaging to your health, happiness, and longevity.

For example, regularly getting fewer than six or seven hours of sleep each night doubles your risk of cancer and can increase the likelihood that you’ll develop Alzheimer’s disease. Insufficient sleep can also contribute to major psychiatric conditions such as anxiety and depression.

One key lesson from Walker is if humans had been able to evolve with the ability to get along with less sleep, then we would have. We are most vulnerable to predation and least productive while we sleep. Yet evolutionarily our bodies retained the need for eight hours.

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Insufficient sleep can have serious metabolic and hormonal consequences. When individuals are sleep-deprived, the body essentially enters a state of malnutrition. “If you take the mentality of ‘I’ll sleep when I’m dead,’ ironically, you will have both a shorter life and the quality of that life will be significantly worse as a consequence,” Walker said onstage at our longevity conference this year. He then highlighted a study where young, healthy men were restricted to five hours of sleep for five nights. The result? Their testosterone levels dropped to the equivalent of someone 10 years older. “Five hours a night for five nights will age a man by a decade,” Walker emphasized, noting that this also affects female reproductive hormones such as estrogen and progesterone.

Sleep deprivation also leads to cognitive and metabolic impairments. A study that restricted people to four hours of sleep for four nights found that these individuals, previously with normal blood sugar, became classified as prediabetic by the end of the trial. This underscores the profound metabolic toll that insufficient sleep can take in a very short time.

Convinced yet? Here are 9 tips for optimizing your sleep.

1. Aim for 7-9 hours: Anything less than 7 hours of sleep can lead to significant metabolic, cognitive, and cardiovascular impairments.

2. Improve sleep efficiency: Walker emphasizes that efficiency is crucial. You can get a sense of yours through sleep trackers like Oura or WHOOP. Anything less than 85% (time spent in bed sleeping versus awake) needs attention.

3. Maintain regular sleep patterns: Regularity is more important than quantity when it comes to long-term health benefits. Walker recommends going to bed and waking up at the same time every day, with only a +/- 25-minute variance.

4. Align your sleep with your chronotype: Everyone has a chronotype—whether they’re a morning person or a night owl. Your goal should be to gradually adjust to a healthy sleep schedule that respects your natural tendencies. For example, if you're a night owl, start with a bedtime close to when you feel naturally drowsy, like 11:30 PM, and gradually shift it earlier by 15-30 minutes every few nights. 

5. Time your exercise right: For optimal sleep quality, it's best to finish exercise 90 minutes before bed, allowing your body enough time to cool down.

6. Eat at the right times, too: It’s best to finish eating at least two hours before bed, giving your body time to digest and reducing indigestion during sleep.

7. Manage stress before sleep: To avoid “tired and wired” syndrome before bed, consider journaling, taking a hot shower, meditation, or catching up with a friend.

8.    Practice good sleep hygiene: An hour before bedtime, lower the lights in your room by 70%. If you need to use your phone, do it only while standing, and put it away when you lie down. Remove clocks from view to avoid watching the time pass.

9.  Monitor yourself for sleep apnea: Sleep apnea, a condition where breathing repeatedly stops and starts during sleep, reduces oxygen levels and can lead to increased risks of heart disease, diabetes, and cognitive decline. Your doctor can order a sleep study, or you can use tools like the SnoreLab app to track signs like loud snoring or gasping for air. If symptoms appear, seek professional evaluation.

Excerpted from Longevity Guidebook: How to Slow, Stop, and Reverse Aging — and NOT Die from Something Stupid