Chronic sleep deprivation refers to not getting enough sleep per 24hrs for one or multiple nights. Chronic Sleep deprivation can happen due to1-

· Medical conditions like pain

· Sleep disorders

· Work demands which include extended work hours and shift work

· Social and domestic responsibilities

· Bedtime Procrastination

We are becoming a chronically sleep deprived society due to above reasons without understanding what harm it is doing to our health. Whenever I see a patient with chronic sleep deprivation I make sure that I explain to them how chronic sleep deprivation is damaging their health. In this blog I am summarizing what I tell my patients about harmful effects of chronic sleep deprivation to bring a meaningful change in their Sleep behavior.

What happens if adults chronically restrict night sleep to <7-9hrs?

Chronic sleep deprivation to <7-9hrs of sleep every night affects most of the body systems unlike acute total sleep deprivation which have mainly neurocognitive deficits.

1. Increased Sleep Propensity during daytime

· If sleep is chronically restricted to <6hrs, one feels sleepier during daytime as assessed by Multiple sleep latency test (MSLT) 2

· This increases the risk of road traffic and occupational accidents

2. Sleep architecture may be preserved despite poor cognition

· Amount of Slow wave sleep is preserved even after chronic sleep restriction to 4-7hrs per night3

· Slow wave sleep has been shown to be associated with daytime cognitive functions

· Cognitive functions can deteriorate even when slow wave sleep is preserved if you are chronic sleep restricted to 4-7hrs per night3

· This is very important to understand in today’s world, where gadgets are used to monitor sleep. Do not think that you have normal cognitive function if your gadget is showing normal slow wave sleep while you are chronic sleep restricted to 4-7hrs per night

3. Bad Cardiovascular and metabolic health

· Both men and women with a usual sleep duration of 7 h had the best survival4

· Sleeping <6hrs increases odds for Hypertension5

· Sleeping more and less than 7.7 h/night had an increased BMI4

· Sleep times ≤ 6h or ≥ 9h/night were associated with an increased prevalence of type 2 diabetes and impaired glucose tolerance.

· Persistent short (<5hrs) or long sleep (>9hrs) or increasing sleep duration in late adulthood was associated with increased risk of all- cause mortality, especially from cardiovascular causes6

· Shift workers experience reduced sleep time and circadian disruption which leads to poor cardiovascular health7

· Decrease of N3 and REM sleep with aging increases BMI by 3.3Kg/m2 in males and 4.4Kg/m2 in females.8 This is worrisome as an increase of 1Kg/m2 in BMI increases risk of developing diabetes mellitus by 19% 9and, for persons with BMI more than 25, 6% higher risk of all-cause mortality.10

4. Increased Driving accidents

· Sleeping <6hrs increases road traffic accidents11

· Sleep deprivation leads to worse driving control as compared to driving control under the influence of alcohol. Intake of coffee does not improve driving performance after sleep deprivation12

5. Impaired Cognition

· Restricting sleep to <7hrs per night chronically leads to cumulative deficits in cognitive performance functions

· Cognitive impairment is worse after restricted daytime sleep as compared to restricted night time sleep, which means shift workers suffer more cognitive impairment

· Study have shown that Short sleep duration (<6hrs) might be an early marker of Alzheimer disease.13

6. Altered Endocrine profile in the evening

· Restricting sleep to 4hrs per night for 6nights leads to elevated levels of evening Cortisol, sympathetic activity, decreased thyrotropin levels and decreased glucose tolerance levels14

· Increased Cortisol levels make it difficult to fall asleep and increased sympathetic activity is harmful for cardiovascular health

7. Impaired Immune function

· Studies have shown that sleep or sleep loss influence immune function.15,16

· Shorter sleep duration on the two nights before the vaccination predicted fewer antibodies 1 and 4 months later.17

8. Negative effects on Mind

· Sleep deprived individuals are irritable, impulsive, have more negative emotions, prone to errors and accidents18

· Bedtime procrastination increases risk for depression, anxiety and Insomnia. 19Bedtime procrastination is a habit where individuals push back sleeping time for leisure activities by engaging more on smart phones.

· Sleep deprivation at workplace leads to lower job satisfaction, decreased charisma of others, decreased helping behavior among colleagues and increased hostility20

9. Impaired regulation of appetite

· Sleep deprived individuals have increased ghrelin and decreased Leptin levels which increases appetite

· Increased appetite leads to increased eating which may lead to obesity

10. Altered reproductive health

· Patients with Non-apnea sleep disorders leading to sleep deprivation are at increased risk of developing female infertility21

· Sleep duration of <6hrs or >9hrs is associated with poor sperm health22,23

11. Negative influence on work performance

a. Waking up at night for texting or emailing affects work performance next day

· Waking up at night for texting or emailing leads to chronic sleep deprivation. This leads to next day sleepiness, fatigue, impaired mood, motivation and attention24

· People who wake up for texting or mailing attribute their symptoms to causes other than sleep deprivation24

· They are 6.4 times more likely for drowsy driving related accidents, 4.8 times more likely to miss work and 2.2 times more likely for errors at work24

b. Extended duration work shifts (24-28hrs) in Physicians affects their performance

· Resident physicians obtained less than 4 hr of spontaneous overnight sleep on 92% of extended-duration work shifts, an amount insufficient to prevent serious neurobehavioral performance impairment. 25

c. Sleep restricted (5.6hrs per night sleep) individuals feel groggy on awakening (Sleep Inertia) at night and can commit errors in decisions

· Cognitive performance in sleep-restricted (5.6hrs per night sleep) individuals was worse within 2 min of awakening, remained worse across the dissipation of sleep inertia, was worse during the biological night, and worsened as days of insufficient sleep increased. This have implications for all individuals needing to perform tasks quickly after awakening like Physicians26

How long it takes to recover following chronic sleep restriction?

Studies have shown that if individuals are chronically sleep restricted for 7nights to <5hrs per night, then either two 10hrs or three 8hrs sleep opportunities are required to recover performance to baseline levels.27,28

Effects of sleep restriction on performance can be mitigated by extending sleep prior to sleep restriction.29 This has been referred to as “Banking Sleep” and is one of the recommendations for athletes to maintain their performance prior to any major sporting events.30

At this stage we do not know whether we can reverse all the damage caused by chronic sleep deprivation by extending the sleep time in sleep deprived people. My advice is to change your habits now to avoid further sleep deprivation and more damage to your health.

Common ineffective Strategies to overcome chronic Sleep deprivation in adults with harmful cardiovascular and metabolic effects

When we sleep less than what is required we accumulate “Sleep debt”. People adopt following strategies to pay their sleep debt-

1. Extending sleep duration over the weekends: Due to social or work demands people are sleeping less on weekdays and try to extend their sleep time on weekends.31,32 One can increase sleep time over the weekend in two ways-

a. Later wake up times than weekdays: This has been referred to as catch up sleep at weekends. It has been shown to be associated with increased risk of poor health-related quality of life and anxiety/depression.33

b. Combination of later sleep time and wake time over the weekend: This has been referred to as Social Jet lag. This has been linked with an increased risk of obesity, type 2 diabetes mellitus, and impaired metabolic control in noncommunicable diseases.34-37

2. Naps: Many people try to take naps to overcome sleep deprivation. Naps (<60 or >60min) have been shown to be associated with all-cause mortality and naps >60min duration with cardiovascular disease.38 When people with night time sleep <6hrs took naps (<60 or >60min) it decreased the all-cause mortality but not the incidence of cardiovascular disease.38

A recent study have shown that napping and catch up sleep on weekend paid sleep debt only in 1 in four subjects who restricted their sleep <6hrs.32 75% subjects with sleep debt did not do anything to pay their sleep debt.32 I am worried with this data as these people may not be even aware that their poor health is due to sleep deprivation and they need to take some actions to correct their sleep patterns.

It has been suggested that extending sleep duration over the weekend and taking naps are not good strategies for paying your sleep debt or to prevent metabolic complications arising due to chronic sleep deprivation.32,39

Message for health policy makers based on harmful consequences of chronic sleep restriction

It has been shown that Degree of belief that insufficient sleep can cause outcomes such as moodiness, occupational problems, and health problems may impact whether an individual is contemplating/attempting to change their sleep-related behaviors. Targeting these key messages about the associations between sleep health with moodiness and weight gain in informational material may enhance education/outreach efforts aimed at adults. 40

Links to other blogs:

1. Sleep- Foundation of Health https://www.rem42.ai/blog/sleep-is-the-foundation-of-health/

2. How to sleep well at night? https://www.rem42.ai/blog/how-to-sleep-well-at-night/

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