Does Sleep Improve Longevity?

This week, we are exploring the research on sleep and longevity. This is the third in a four-part series on how to play hard, work hard, and be fully engaged with family, friends and community for as long as possible. [Click here to see the first two weeks posts]

For most of us, being fully engaged and productive often comes at the cost of a loss of sleep. In our productivity-driven culture people say they will “sleep when they are dead”, and from what I have read, those people will get their wish more quickly than they may like. Today, I hope to illustrate why getting at least 7 hours of sleep may be the magic pill to improving health, longevity, intelligence, sexuality, productivity, and likeability. 

Last week we talked about how meditation could change the balance of our autonomic nervous system, which is the part of our nervous system we don’t control from that of sympathetic (a.k.a fight or flight) to parasympathetic (a.k.a. rest, healing and digestion) [1,2]. When our sympathetic nervous system is overactivated for days, weeks or months, we experience more stress and our bodies experience more inflammation. [3] Sleep also helps lower sympathetic tone, which may have health benefits.
To help me understand the benefits of sleep better, I looked first to one of the most prolific researchers on sleep, Matt Walker of UC Berkeley. On a recent podcast Dr. Walker said, “If there is one central, common pathway through which we can understand almost all aspects of the deleterious impact of insufficient sleep, it is through the autonomic nervous system, and specifically an excessive leaning on the fight or flight branch of the nervous system.” To put it more simply, if the lack of sleep leads to more fight or flight, then this high sympathetic tone may be part of the reason we see poor sleep associated with poor immune function, heart disease and diabetes to name a few possible side effects. 

So what have the studies shown? From a health perspective, we have seen that adequate sleep lowers the risk of some cancers. [4,5,6]  Sleep also seems important for lowering risk of diabetes [7,8] and maintaining heart health. One study showed that 6 or less hours of sleep led to a 200-300% increased risk of coronary artery calcification. [9]

When considering longevity, PNAS (Proceedings of the National Academy of Sciences) published an article that found limiting sleep to less than 6 hours for 1 week changed the activity of 711 genes or about 3% of the total genome. [10] It found that the sleep reduction down-regulated genes that were associated with healthy immune functioning and up-regulated genes associated with chronic inflammation and tumor production. In other words, <6 hours of sleep predisposes people to chronic inflammation and tumor genesis or inflam-aging.

Some of the more interesting sleep associations I have found includes sexuality, productivity, and likeability. [11,12,13] If we want to be socially engaged, apparently allowing enough sleep is important. One of Dr. Walkers recent studies shows that sleep loss causes social withdrawal and loneliness. Sleep also seems to impact the brain’s ability to encode new information. This has broad implications, but it’s particularly important for students, or anyone wanting to learn new things such as new acquaintances’ names and the elderly, who are at risk for dementia. [14,15,16] 

Sleep is stigmatized as laziness, but from the studies I have read, adequate sleep can actually lead to a healthier, happier you.  Putting it together, sleep seems improve longevity through lowering the likelihood of disease, accidents and decrepitude. Most people need to allow at least 7 hours of sleep nightly. [17] It may be hard to find the time, but from a risk (loss of time) benefit (improved longevity, social engagement, cognitive performance) perspective, I feel the time investment is repaid by the significant benefits.

So you may ask how can I begin to give myself adequate sleep.  Dr. Walker suggests there are three key factors to maintaining a healthy sleep pattern:
1. Regularity: Maintain consistent sleep and rise times.  
2. Darkness: Try to limit screen time and dim home lights the hour before bed. Darkness is needed for melatonin secretion.
3. Cooler room temperatures: Turn down the heat. Your core body temperature is supposed to drop two to three degrees.

I interpret his three keys as ways to help maintain circadian rhythm, which is an internal clock that regulates our sleep/ wake cycle.  
*Blue light simulates morning light, which at night can hurt sleep. So, the timing of your blue light exposure is important. [15,16,17,18,19,20]

*Morning time outside gives your photoreceptors strong circadian cues. 

*In the evenings, research shows it is best to avoid all blue light (phone screens, computers, TVs), but if you need to work on your computers or phone considers using night shift on iPhones or f.lux that can adjust color based on location and time or you can even use the super cool (not really) blue blocking glasses.  [21,22,23,24,25]

*When you are ready for sleep, a quiet room is also important. You may want to consider noise blocking devices such as kokoon or if you have a noisy partner, there is always the “sleep divorce” as popularized recently by Carson Daly.

*There is evidence that meditation can improve sleep. Please see last weeks post for suggestion on meditation apps.  [26]

*Lastly. CBTI (Cognitive Behavioral therapy for insomnia) has shown great efficacy in improving sleep. [27] Apps such as CBTI coach (from the VA, Stanford SOM and the DoD) and Pzziz are both effective and well  researched.

That is it for this week.  Next week, we will talk about what the research really shows us on nutrition and longevity, and what steps you can take towards a healthier, happier you!

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1. Koopman, F.A., Stoof, S. P., Straub, R. H. , van Maanen, M. A. , Vervoordeldonk, M. J. , Tak,  P. P. (2011) Restoring the Balance of the Autonomic Nervous System as an Innovative Approach to the Treatment of Rheumatoid Arthritis. Mol Med; 17(9-10): 937–948. Published online 2011 May 20. doi: 10.2119/molmed.2011.00065

2. Amihai, I., Kozhevnikov, M. (2015). The Influence of Buddhist Meditation Traditions on the Autonomic System and Attention. Biomed Res Int. 731579. Published online 2015 Jun 4. doi: 10.1155/2015/731579

3. Bellinger, D.L.1, Lorton, D. (2018). Sympathetic Nerve Hyperactivity in the Spleen: Causal for Nonpathogenic-Driven Chronic Immune-Mediated Inflammatory Diseases (IMIDs)? Int J Mol Sci. 2018 Apr; 19(4): 1188. Published online 2018 Apr 13. doi: 10.3390/ijms19041188
4. Thompson et al., 2011 Colorectal cancer and sleep: Short duration of sleep increases risk of colorectal adenoma. Cancer. Feb 15;117(4):841-7. doi: 10.1002/cncr.25507.
5. Irwin et al., 1994. Sleep deprivation reduces natural killer cells: Partial sleep deprivation reduces natural killer cell activity in humans. Psychosomatic Medicine. 56(6):493–498. 

6. Hakim et al., 2014. Tumors grow more in sleep deprived mice: Fragmented sleep accelerates tumor growth and progression through recruitment of tumor-associated macrophages and TLR4 signaling. Cancer Res. Mar 1;74(5):1329-37. doi: 10.1158/0008-5472.CAN-13-3014

7. Knutson et al. 2007. The metabolic consequences of sleep deprivation. Sleep Medicine Reviews. Volume 11, Issue 3, Pages 163-178.. https://doi.org/10.1016/j.smrv.2007.01.002 

8. Sheen et al. 1996. Relationships between sleep quality and glucose regulation in normal humans. American journal of physiology. 01 AUG 1996. https://doi.org/10.1152/ajpendo.1996.271.2.E261 

9.King et al. 2008. Short sleep duration and incident coronary artery calcification. JAMA 300(24):2859-66. doi: 10.1001/jama.2008.867.

10. Möller-Levet CS et al. 2019 Effects of insufficient sleep on circadian rhythmicity and expression amplitude of the human blood transcriptome. Proc Natl Acad Sci U S A. Mar 19;110(12):E1132-41. doi: 10.1073/pnas.1217154110.

11. Cote et al 2013. Sleep deprivation lowers reactive aggression and testosterone in men. Biological Psychology. Volume 92, Issue 2, February 2013, Pages 249-256. https://doi.org/10.1016/j.biopsycho.2012.09.011

12. Ben Simon, E., Walker, M.P. 2018 Sleep loss causes social withdrawal and loneliness. Nat Commun 9, 3146 doi:10.1038/s41467-018-05377-0

13. Rosekind et al. 2010. The Cost of Poor Sleep: Workplace Productivity Loss and Associated Costs. Journal of Occupational and Environmental Medicine: January 2010 - Volume 52 - Issue 1 - p 91-98. doi: 10.1097/JOM.0b013e3181c78c30.

14. Walker MP. 2008. Sleep-dependent memory processing. Harv Rev Psychiatry. 16(5):287-98. doi: 10.1080/10673220802432517.

15.Walker, MP. 2008. Cognitive consequences of sleep and sleep loss . Sleep Medicine. Volume 9, Supplement 1, September 2008, Pages S29-S34

16. Mander et al. 2013. Prefrontal atrophy, disrupted NREM slow waves and impaired hippocampal-dependent memory in aging. Nature Neuroscience,. Volume 16, pages 357–364.

17. NSF -https://www.sleepfoundation.org/articles/how-much-sleep-do-we-really-need

18. Shechter et al. 2017. Blocking nocturnal blue light for insomnia: A randomized controlled trial. Journal of Psychiatric Research. Volume 96, Pages 196-202. doi: 10.1016/j.jpsychires.2017.10.015
19. Zimmerman et al. 2019. Neuropsychological Function Response to Nocturnal Blue Light Blockage in Individuals With Symptoms of Insomnia: A Pilot Randomized Controlled Study, Journal of the International Neuropsychological Society, Volume 25, Issue 7, pp. 668-677. 
20. Czeisler CA (2013) Perspective: Casting light on sleep deficiency. Nature 497(7450):S13

21. Cajochen et al. 2011. Evening exposure to a light-emitting diodes (LED)-backlit computer screen affects circadian physiology and cognitive performance. Journal of Applied Physiology. 110(5):1432-8. doi: 10.1152/japplphysiol.00165.2011.
22. Czeisler et al. 2015. Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness. PNAS- Proceedings of the National Academy of Sciences of the United States of America. 112 (4) 1232-1237;
23. Lockley et al. 2003.  High Sensitivity of the Human Circadian Melatonin Rhythm to Resetting by Short Wavelength Light. The Journal of Clinical Endocrinology & Metabolism, Volume 88, Issue 9, Pages 4502–4505, https://doi.org/10.1210/jc.2003-030570

24.Burkhart et al. 2009 Amber lenses to block blue light and improve sleep: a randomized trial. Chronobiol Int. 2009 Dec;26(8):1602-12. doi: 10.3109/07420520903523719.
25. Van der Lely, S et al. 2015. Blue blocker glasses as a countermeasure for alerting effects of evening light-emitting diode screen exposure in male teenagers. J Adolesc Health. 56(1):113-9. doi: 10.1016/j.jadohealth.2014.08.002

26. Black, D et al. 2015. Mindfulness Meditation and Improvement in Sleep Quality and Daytime Impairment Among Older Adults With Sleep Disturbances A Randomized Clinical Trial. JAMA Internal Medicine. 175(4):494-501. doi:10.1001/jamainternmed.2014.8081

27. Jacobs et al. 2004. Cognitive behavior therapy and pharmacotherapy for insomnia: a randomized controlled trial and direct comparison.  Arch Intern Med. 2004 Sep 27;164(17):1888-96.