Longevity, the pursuit of a healthier and longer life, is an ancient aspiration that unites various fields. Those at the forefront of this quest often don several hats, balancing roles as physicians, professors, entrepreneurs, and even celebrities at times.
Yet despite their hectic schedules, there’s one crucial slot in the day that they never mess with: sleep time.
It might be ironic that one of the most potent drugs longevity scientists swear by is accessible to us all. But hopefully after reading this article, you’ll be convinced to follow in their footsteps and believe in the longevity powers of a good night’s sleep.
Sleep: An Overlooked Pillar of Longevity
Many experts consider sleep, along with nutrition, exercise, stress management, smoking abstinence, and alcohol moderation, as one of the six pillars of longevity. These are six modifiable lifestyle factors that, when optimized, can significantly enhance a person’s lifespan.
A study from earlier this year by the American College of Cardiology[1], involving 172,321 participants, revealed that individuals with good sleep patterns enjoyed an extended life expectancy of 4.7 years for men and 2.4 years for women.
However, in the 24-hour society we live in, sleep seemingly gets the least attention out of all the pillars.
So How Deep Is Our Sleep Problem?
As we’ve already started unraveling the longevity benefits of the Zs we’re missing out on, let’s address the depth of our society’s sleep problem.
According to the Centers for Disease Control and Prevention[2], a staggering 1 in 3 adults in the US admits to not receiving adequate sleep daily. Plus, nearly 40% of adults find themselves unintentionally dozing off during the day at least once a month. To compound this issue, an estimated 50 to 70 million Americans grapple with chronic, ongoing sleep disorders.
These statistics merit a closer look and a more nuanced understanding of sleep as a phenomenon.
The Science of Sleep
Sleep is an evolutionarily conserved process with almost all creatures experiencing some form of it. The stages of sleep, known as sleep architecture, are what vary between species.
In humans[3], we cycle between REM (rapid eye movement) sleep and three stages of non-REM sleep several times in a typical night. Stage 1 of NREM is a transition from wakefulness to light sleep. Stage 2 is a lighter sleep before moving to deeper stages. Stage 3, when brain waves become slowest, is the restorative deep sleep. REM sleep starts about 90 minutes after sleep onset. This is when our minds venture into vivid dreamscapes while our bodies remain temporarily locked in muscle paralysis
Two key mechanisms regulate sleep: circadian rhythms and sleep-wake homeostasis. Circadian rhythms control various functions, such as body temperature, metabolism, and hormone release, aligning our sleep-wake cycle with the day-night cycle. Sleep-wake homeostasis builds up the need for sleep as the duration of wakefulness increases.
Why Do We Need Sleep for Longevity?
For decades, science has recognized sleep for its restorative capacities. Generally, some of these functions include muscle repair, removal of toxins, and memory consolidation.
Today in the age of longevity, researchers are studying sleep’s role in offsetting the hallmarks of aging; the fundamental biological mechanisms that drive aging. With sleep deprivation being studied as an accelerator of biological aging[4], it’s no wonder that these hallmarks go awry with poor sleep.
One study involving hospital physicians[5] discovered DNA damage following an overnight shift with acute sleep loss, starkly contrasting the minimal DNA damage observed after three nights of regular sleep. Similarly, telomeres, which are protective caps on DNA strands, tend to shorten with poor sleep. In a study examining female nurses engaged in rotating night shifts[6], those who averaged less than six hours of sleep per day exhibited shorter telomeres compared to their well-rested counterparts.
Research is still ongoing to elucidate the links between sleep and other hallmarks of aging.
Both Duration and Regularity of Sleep Affect Longevity
So is following the recommended 7–9 hours of sleep[7] enough for longevity? Well, it turns out that both duration and regularity of sleep affect all-cause mortality.
In one study[8], scientists followed over 21,000 Finnish twins for more than 22 years. They studied the twins’ sleep patterns and looked at their longevity. Duly, researchers found that those who slept less than 7 hours had a 24% increased risk of all-cause mortality while those who slept more than 8 hours had a 17% increased risk.
Another study from last September[9], involving 60,977 UK participants, suggests sleep regularity as a stronger predictor of mortality risk. Participants with more regular sleep patterns had a 20% to 48% lower risk of all-cause mortality.
Sleep and Age-Related Diseases
While scientists are still trying to understand the exact mechanisms that make poor sleep a predictor of all-cause mortality, poor sleep has been linked to several age-related diseases.
For example, insufficient sleep has been recognized as a factor in elevating the risk of type 2 diabetes, with notable implications for Hemoglobin A1c levels, a crucial indicator of long-term blood sugar control[10].
Additionally, conditions like hypertension, stroke, coronary heart disease, and cardiac arrhythmias have been notably more prevalent among those suffering from sleep disturbances than their peers enjoying restful sleep[10]. In laboratory settings, it’s been discovered that sleep deprivation triggers metabolic alterations that might correlate with obesity[10].
On the neurocognitive level, a study revealed that even a single night of sleep deprivation can lead to an upsurge in beta-amyloid, a brain protein linked to impaired cognitive function and the onset of Alzheimer’s disease[11].
Tips for Improved Sleep Hygiene
While some may need a minute to process the insidious effects of sleep deprivation on our health, good news still awaits. For many, these effects can be reversed with better sleep hygiene. Here are some starters from Dr. Emmanuel Mignot, the director of the Stanford Center for Sleep Sciences and Medicine:
“Getting solid light exposure — preferably with outside light — during the day, keeping the sleep environment dark at night, exercising regularly but not too close to bedtime, not drinking alcohol and caffeine around bedtime, and avoiding heavy nighttime meals all contribute to healthy sleep. And, of course, make sure any sleep disorder is treated.”
Believe it or not, research also points to the potential benefits of daytime napping, particularly when it comes to increasing brain volume[12].
How to Track Your Sleep?
As our curiosity for understanding sleep grows, so does the popularity of sleep-tracking tools. These come in various forms, including wearable smartwatches and rings, and even devices that rest under your mattress. Numerous tracking apps also exist.
Most commonly, these tools rely on accelerometers to gauge movement throughout your sleep. Then, this data is subjected to analysis through specialized algorithms, allowing the estimation of both sleep duration and quality. Some devices go a step further by measuring parameters like heart rate and respiration rates, which exhibit significant variations during different sleep stages as discussed earlier.
Did you know that you can use this sleep data to estimate your biological age?
The Rejuve Longevity App is your go-to tool for measuring the impact of your lifestyle factors, including sleep metrics, on your biological age.
As you track your own longevity, you also earn special RJV tokens which you can redeem for discounts on supplements, medical tests, longevity therapies, and more!
References:
1- Getting Good Sleep Could Add Years to Your Life. (n.d.). American College of Cardiology. https://www.acc.org/About-ACC/Press-Releases/2023/02/22/21/35/Getting-Good-Sleep-Could-Add-Years-to-Your-Life
2-Do You Get Enough Sleep? | CDC. (2020, June 15). Www.cdc.gov. https://www.cdc.gov/chronicdisease/resources/infographic/sleep.htm
3-National Institute of Neurological Disorders and Stroke (2022) Brain Basics: Understanding Sleep | National Institute of Neurological Disorders and Stroke, www.ninds.nih.gov. Available at: https://www.ninds.nih.gov/health-information/public-education/brain-basics/brain-basics-understanding-sleep.
4-Wang, X. et al. (2023) ‘Day-to-day deviations in sleep parameters and biological aging: Findings from the NHANES 2011–2014’, Sleep Health [Preprint]. Available at: https://doi.org/10.1016/j.sleh.2023.07.018.
5-Cheung, V. et al. (2018) ‘The effect of sleep deprivation and disruption on DNA damage and health of doctors’, Anaesthesia, 74(4), pp. 434–440. Available at: https://doi.org/10.1111/anae.14533.
6-Liang, G. et al. (2011) ‘Associations between Rotating Night Shifts, Sleep Duration, and Telomere Length in Women’, PLoS ONE. Edited by J. Vina, 6(8), p. e23462. Available at: https://doi.org/10.1371/journal.pone.0023462.
[7] National Sleep Foundation (2020) How Much Sleep Do You Really Need?, National Sleep Foundation. Available at: https://www.thensf.org/how-many-hours-of-sleep-do-you-really-need/.
[8] Hublin, C. et al. (2007) ‘Sleep and Mortality: A Population-Based 22-Year Follow-Up Study’, Sleep, 30(10), pp. 1245–1253. Available at: https://doi.org/10.1093/sleep/30.10.1245.
[9] Daniel P Windred, Angus C Burns, Jacqueline M Lane, Richa Saxena, Martin K Rutter, Sean W Cain, Andrew J K Phillips, Sleep regularity is a stronger predictor of mortality risk than sleep duration: A prospective cohort study, Sleep, 2023; zsad253, https://doi.org/10.1093/sleep/zsad253
[10] CDC (2019) CDC — Sleep and Chronic Disease — Sleep and Sleep Disorders, Centers for Disease Control and Prevention. Available at: https://www.cdc.gov/sleep/about_sleep/chronic_disease.html.
[11] National Institutes of Health (2018) Sleep deprivation increases Alzheimer’s protein, National Institutes of Health (NIH). Available at: https://www.nih.gov/news-events/nih-research-matters/sleep-deprivation-increases-alzheimers-protein.
[12] Paz, V., Dashti, H.S. and Garfield, V. (2023) ‘Is there an association between daytime napping, cognitive function, and brain volume? A Mendelian randomization study in the UK Biobank’, Sleep Health [Preprint]. Available at: https://doi.org/10.1016/j.sleh.2023.05.002.
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