Link Between Sleep and Longevity: A Comprehensive Review

In a nutshell

  1. Discover the intricate relationship between sleep and longevity, and learn how every restful night can contribute significantly to your health and lifespan.
  2. You’ll find that sleep is far more than just a sweet escape at the end of the day. It’s an essential, complex process intricately linked to your health and longevity. From the critical functions of sleep and the fascinating discovery of the glymphatic system, to the effects of aging on sleep and the risks posed by common sleep disorders, there’s so much to explore.
  3. Unravel these connections, understand the importance of the recommended seven to eight hours of sleep, and discover how you can navigate changes in sleep patterns as you age. Because when it comes to your health and longevity, every good night’s sleep counts!

There is a saying, “Sleep is the best medicine.” This simple phrase captures the essence of a profound truth. The importance of sleep cannot be overstated, particularly when considering its relationship with longevity. This article seeks to delve into the fascinating, yet intricate connection between sleep quality and longevity, supported by substantial scientific evidence. Rest assured, even if you’re not a sleep scientist, this article is written to be accessible and enjoyable for everyone.

The Importance of Sleep

Sleep is not merely a time of rest and recovery. It serves vital physiological functions, including memory consolidation, cognitive function enhancement, emotional regulation, and bodily regeneration.1 Brinkman JE, Reddy V, Sharma S. Physiology of Sleep. 2022 Sep 19. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan–. PMID: 29494118. PubMed Source Sleep is so fundamental to our well-being that prolonged sleep deprivation can lead to serious health consequences and even death.2 Everson CA, Bergmann BM, Rechtschaffen A. Sleep deprivation in the rat: III. Total sleep deprivation. Sleep. 1989 Feb;12(1):13-21. doi: 10.1093/sleep/12.1.13. PMID: 2928622. PubMed Source

Despite the intuitive understanding that sleep is essential for our bodies, the scientific community grappled for a long time with understanding its exact functions. Then, a groundbreaking discovery unfolded in 2013, shedding light on one of sleep’s most significant roles.3 Xie L, Kang H, Xu Q, Chen MJ, Liao Y, Thiyagarajan M, O’Donnell J, Christensen DJ, Nicholson C, Iliff JJ, Takano T, Deane R, Nedergaard M. Sleep drives metabolite clearance from the adult brain. Science. 2013 Oct 18;342(6156):373-7. doi: 10.1126/science.1241224. PMID: 24136970; PMCID: PMC3880190.PubMed Source This discovery was the glymphatic system – a waste clearance pathway in our brains that becomes particularly active during sleep.

This newly discovered system functions much like the lymphatic system found elsewhere in the body, but it is unique to the brain. Its primary role is to clear away metabolic waste products that accumulate in the spaces between brain cells. During our wakeful hours, the brain tirelessly works, producing waste that needs to be cleared away. This is where the glymphatic system steps in.

This waste includes harmful proteins such as beta-amyloid, which is implicated in the development of neurodegenerative diseases like Alzheimer’s. And that’s what the research supports, poor sleep quality is associated with an increase in beta-amyloid plaques, one of the key hallmarks of Alzheimer’s disease.4 Bubu OM, Brannick M, Mortimer J, Umasabor-Bubu O, Sebastião YV, Wen Y, Schwartz S, Borenstein AR, Wu Y, Morgan D, Anderson WM. Sleep, Cognitive impairment, and Alzheimer’s disease: A Systematic Review and Meta-Analysis. Sleep. 2017 Jan 1;40(1). doi: 10.1093/sleep/zsw032. PMID: 28364458. PubMed Source Therefore, a well-functioning glymphatic system during sleep can have profound implications for our long-term brain health and, consequently, our longevity.


The Connection Between Sleep and Longevity

Now, let’s delve deeper into the relationship between sleep and longevity. Understanding this link between can be the key to unlocking a healthier and more fulfilled life.

Numerous scientific studies have shed light on the complex interactions between sleep and longevity, revealing that our sleep patterns can significantly impact our lifespan. The big insight we can get from long-term studies following groups of people over time.

For example, a unique Finnish twin study that followed twins over their lifespan found a link between sleep duration and all-cause mortality.5Hublin C, Partinen M, Koskenvuo M, Kaprio J. Sleep and mortality: a population-based 22-year follow-up study. Sleep. 2007 Oct;30(10):1245-53. doi: 10.1093/sleep/30.10.1245. PMID: 17969458; PMCID: PMC2266277. PubMed Source The researchers discovered that people who regularly sleep about seven hours per night have the highest longevity. Interestingly, both shorter (less than seven hours) and longer sleep durations (more than nine hours) were associated with reduced lifespan.

This pattern is consistent across different populations and other studies.6 Kripke DF, Garfinkel L, Wingard DL, Klauber MR, Marler MR. Mortality associated with sleep duration and insomnia. Arch Gen Psychiatry. 2002 Feb;59(2):131-6. doi: 10.1001/archpsyc.59.2.131. PMID: 11825133. PubMed Source 7Aurora RN, Kim JS, Crainiceanu C, O’Hearn D, Punjabi NM. Habitual Sleep Duration and All-Cause Mortality in a General Community Sample. Sleep. 2016 Nov 1;39(11):1903-1909. doi: 10.5665/sleep.6212. PMID: 27450684; PMCID: PMC5070744. PubMed Source

This is not to say that sleeping for at least seven hours will guarantee a longer life, but targeting seven to eight hours a night should be a must. It is important to understand that sleep is part of the puzzle. Other critical pieces of this puzzle are regular exercise, balanced nutrition, and mental self-care.

Adequate sleep forms the foundation upon which these other healthful habits can thrive. It optimizes physical recovery, enhances cognitive function, and regulates mood, making it easier to maintain a regular exercise routine, make nutritious dietary choices, and practice effective self-care strategies.

Sleep Quality Matters

Not just the quantity of sleep matters; quality is equally crucial. Sleep quality refers to how well you sleep, which includes factors like sleep efficiency (meaning the time you actually spend sleeping while you’re in bed), sleep disturbances, use of sleep medication, and daytime dysfunction due to sleepiness.8 Buysse DJ, Reynolds CF 3rd, Monk TH, Berman SR, Kupfer DJ. The Pittsburgh Sleep Quality Index: a new instrument for psychiatric practice and research. Psychiatry Res. 1989 May;28(2):193-213. doi: 10.1016/0165-1781(89)90047-4. PMID: 2748771. PubMed Source

Poor sleep quality, such as difficulties falling asleep, frequent awakenings, and non-restorative sleep, has been linked to various health problems, including cardiovascular disease, diabetes, obesity, and depression.9 Liu TZ, Xu C, Rota M, Cai H, Zhang C, Shi MJ, Yuan RX, Weng H, Meng XY, Kwong JS, Sun X. Sleep duration and risk of all-cause mortality: A flexible, non-linear, meta-regression of 40 prospective cohort studies. Sleep Med Rev. 2017 Apr;32:28-36. doi: 10.1016/j.smrv.2016.02.005. Epub 2016 Mar 3. PMID: 27067616. PubMed Source These conditions, in turn, can significantly shorten lifespan.

This underscores the importance of nurturing your sleep quality by embracing good sleep hygiene and creating a soothing, optimized sleep environment. As we age, it’s important to remember that changes in our sleep patterns and structures are normal. Being aware of these changes and adjusting accordingly can play a crucial role in maintaining good sleep health and overall well-being.

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Sleep during Aging: Role of Deep Sleep

As we age and hit our fifth decade, sleep patterns tend to change and these changes can significantly affect the quality of sleep and overall health.10 Mander BA, Winer JR, Walker MP. Sleep and Human Aging. Neuron. 2017 Apr 5;94(1):19-36. doi: 10.1016/j.neuron.2017.02.004. PMID: 28384471; PMCID: PMC5810920. PubMed Source Older adults often have trouble falling asleep and more trouble staying asleep than when they were younger. They may wake up more often during the night and find it harder to get back to sleep. Additionally, the amount of time spent in the deep, restorative stages of sleep, so-called deep sleep, tends to decrease with age.

Now, let’s discuss the different stages of sleep. Sleep is typically divided into two main categories: Non-Rapid Eye Movement (NREM) sleep and Rapid Eye Movement (REM) sleep. Each of these categories is associated with specific brain waves and neuronal activity.

  1. NREM sleep is further divided into three stages:
    • N1 (Stage 1): This is the lightest stage of sleep, the transition phase where you feel yourself drifting off. It’s a relatively brief period of time, usually lasting several minutes.
    • N2 (Stage 2): This is the first stage of true sleep, lasting 10 to 25 minutes. Your heart rate begins to slow, and your body temperature decreases. Despite being a light stage of sleep, most of your sleep time is spent in this stage.
    • N3 (Stage 3): Often referred to as deep NREM sleep, or Slow-Wave Sleep, it’s the most restorative stage of sleep. It’s the period when the body repairs and regrows tissues, builds bone and muscle, and strengthens the immune system. As you age, you spend less time in this deep sleep stage.
  2. REM sleep: This stage usually begins about 90 minutes after you fall asleep. Your eyes move quickly behind your lids, and your brain waves are similar to those when you are awake. This is the stage where intense dreaming occurs due to increased brain activity. REM sleep is thought to play a role in memory consolidation. REM sleep tends to hold relatively steady as we age, with notable changes only starting to appear when people reach their 80s or later.

Deep NREM sleep, or slow-wave sleep, has been particularly associated with longevity. A decrease in slow-wave sleep is linked to an increased risk of hypertension, a known risk factor for reduced lifespan. During deep sleep, our bodies produce growth hormone, restore energy, and repair tissues, all vital processes that help maintain our health and slow down aging.


Sleep Disorders and Longevity

Sleep disorders disrupt the quality, timing, or amount of sleep a person gets and can significantly impact longevity. Some of the most common sleep disorders include insomnia, sleep apnea, restless legs syndrome, and narcolepsy. For instance, people with obstructive sleep apnea, characterized by repeated episodes of partial or complete blockage of the upper airway during sleep, have an increased risk of cardiovascular disease, stroke, and premature death.11Marshall NS, Wong KK, Liu PY, Cullen SR, Knuiman MW, Grunstein RR. Sleep apnea as an independent risk factor for all-cause mortality: the Busselton Health Study. Sleep. 2008 Aug;31(8):1079-85. PMID: 18714779; PMCID: PMC2542953. PubMed Source

Individuals with narcolepsy, a neurological disorder marked by excessive daytime sleepiness and sudden attacks of sleep, often struggle with impaired daily functioning and, in severe cases, are at risk for accidents due to sudden sleep attacks.12Thorpy MJ, Krieger AC. Delayed diagnosis of narcolepsy: characterization and impact. Sleep Med. 2014 May;15(5):502-7. doi: 10.1016/j.sleep.2014.01.015. Epub 2014 Feb 15. PMID: 24780133. PubMed Source

Similarly, those suffering from insomnia, a condition characterized by consistent difficulty in falling asleep, staying asleep, or waking up too early, face a higher risk of developing mental health disorders, heart disease, and diabetes, all of which could potentially lead to a shortened lifespan.13Baglioni C, Battagliese G, Feige B, Spiegelhalder K, Nissen C, Voderholzer U, Lombardo C, Riemann D. Insomnia as a predictor of depression: a meta-analytic evaluation of longitudinal epidemiological studies. J Affect Disord. 2011 Dec;135(1-3):10-9. doi: 10.1016/j.jad.2011.01.011. Epub 2011 Feb 5. PMID: 21300408. PubMed Source

The relationship between sleep disorders and longevity underscores the importance of early detection and treatment. Managing these conditions can not only improve sleep quality and daytime functioning but also potentially extend life expectancy by mitigating the associated health risks.


Recap and final thoughts

In wrapping up, it’s crucial to remember that your sleep plays a pivotal role in your health and longevity. It’s not just about getting enough hours, but also about maintaining the quality of your sleep. Whether due to natural aging or sleep conditions, any disruption to your sleep can potentially lead to health complications that could affect your lifespan. So, it’s worth trying to get those recommended seven to eight hours of quality sleep each night. After all, understanding and adapting to the changes in your sleep patterns as you age, and seeking help when facing sleep disorders, is a significant investment in your overall well-being and longevity.

References

  • 1
    Brinkman JE, Reddy V, Sharma S. Physiology of Sleep. 2022 Sep 19. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan–. PMID: 29494118. PubMed Source
  • 2
    Everson CA, Bergmann BM, Rechtschaffen A. Sleep deprivation in the rat: III. Total sleep deprivation. Sleep. 1989 Feb;12(1):13-21. doi: 10.1093/sleep/12.1.13. PMID: 2928622. PubMed Source
  • 3
    Xie L, Kang H, Xu Q, Chen MJ, Liao Y, Thiyagarajan M, O’Donnell J, Christensen DJ, Nicholson C, Iliff JJ, Takano T, Deane R, Nedergaard M. Sleep drives metabolite clearance from the adult brain. Science. 2013 Oct 18;342(6156):373-7. doi: 10.1126/science.1241224. PMID: 24136970; PMCID: PMC3880190.PubMed Source
  • 4
    Bubu OM, Brannick M, Mortimer J, Umasabor-Bubu O, Sebastião YV, Wen Y, Schwartz S, Borenstein AR, Wu Y, Morgan D, Anderson WM. Sleep, Cognitive impairment, and Alzheimer’s disease: A Systematic Review and Meta-Analysis. Sleep. 2017 Jan 1;40(1). doi: 10.1093/sleep/zsw032. PMID: 28364458. PubMed Source
  • 5
    Hublin C, Partinen M, Koskenvuo M, Kaprio J. Sleep and mortality: a population-based 22-year follow-up study. Sleep. 2007 Oct;30(10):1245-53. doi: 10.1093/sleep/30.10.1245. PMID: 17969458; PMCID: PMC2266277. PubMed Source
  • 6
    Kripke DF, Garfinkel L, Wingard DL, Klauber MR, Marler MR. Mortality associated with sleep duration and insomnia. Arch Gen Psychiatry. 2002 Feb;59(2):131-6. doi: 10.1001/archpsyc.59.2.131. PMID: 11825133. PubMed Source
  • 7
    Aurora RN, Kim JS, Crainiceanu C, O’Hearn D, Punjabi NM. Habitual Sleep Duration and All-Cause Mortality in a General Community Sample. Sleep. 2016 Nov 1;39(11):1903-1909. doi: 10.5665/sleep.6212. PMID: 27450684; PMCID: PMC5070744. PubMed Source
  • 8
    Buysse DJ, Reynolds CF 3rd, Monk TH, Berman SR, Kupfer DJ. The Pittsburgh Sleep Quality Index: a new instrument for psychiatric practice and research. Psychiatry Res. 1989 May;28(2):193-213. doi: 10.1016/0165-1781(89)90047-4. PMID: 2748771. PubMed Source
  • 9
    Liu TZ, Xu C, Rota M, Cai H, Zhang C, Shi MJ, Yuan RX, Weng H, Meng XY, Kwong JS, Sun X. Sleep duration and risk of all-cause mortality: A flexible, non-linear, meta-regression of 40 prospective cohort studies. Sleep Med Rev. 2017 Apr;32:28-36. doi: 10.1016/j.smrv.2016.02.005. Epub 2016 Mar 3. PMID: 27067616. PubMed Source
  • 10
    Mander BA, Winer JR, Walker MP. Sleep and Human Aging. Neuron. 2017 Apr 5;94(1):19-36. doi: 10.1016/j.neuron.2017.02.004. PMID: 28384471; PMCID: PMC5810920. PubMed Source
  • 11
    Marshall NS, Wong KK, Liu PY, Cullen SR, Knuiman MW, Grunstein RR. Sleep apnea as an independent risk factor for all-cause mortality: the Busselton Health Study. Sleep. 2008 Aug;31(8):1079-85. PMID: 18714779; PMCID: PMC2542953. PubMed Source
  • 12
    Thorpy MJ, Krieger AC. Delayed diagnosis of narcolepsy: characterization and impact. Sleep Med. 2014 May;15(5):502-7. doi: 10.1016/j.sleep.2014.01.015. Epub 2014 Feb 15. PMID: 24780133. PubMed Source
  • 13
    Baglioni C, Battagliese G, Feige B, Spiegelhalder K, Nissen C, Voderholzer U, Lombardo C, Riemann D. Insomnia as a predictor of depression: a meta-analytic evaluation of longitudinal epidemiological studies. J Affect Disord. 2011 Dec;135(1-3):10-9. doi: 10.1016/j.jad.2011.01.011. Epub 2011 Feb 5. PMID: 21300408. PubMed Source
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