You know that feeling when you don’t sleep well, and you wake up feeling cranky, over-emotional, and over-tired? This is only a hint of what that sleep deprivation is doing to your body. If you don’t sleep well, it’s going to lead to health issues, both mental and physical, plain and simple.
In fact, I believe sleep is every bit as important for optimal health as healthy food, pure water, and exercise, and I’m not alone in that sentiment. While the exact mechanisms of sleep are still quite a mystery, increasing research is showing that your body’s sleep-wake cycle, or circadian rhythm, plays a central role in multiple body processes
They impact everything from mood and energy levels to disease progression and weight gain. Far from simply helping you to feel alert, proper sleep forms the foundation for your body to function optimally.
Poor sleep can actually impact virtually every aspect of your health, and the reason for this is your circadian rhythm (sleep-wake cycle) actually “drives” the rhythms of biological activity at the cellular level.
We’re only beginning to uncover the fascinating biological processes that take place during sleep. For example, during sleep your brain cells also shrink by about 60 percent, which allows for more efficient waste removal.4
Sleep is also intricately tied to important hormone levels, including melatonin, production of which is disturbed by lack of sleep. This is extremely problematic, as melatonin inhibits the proliferation of a wide range of cancer cell types, as well as triggers cancer cell apoptosis (self-destruction).
Lack of sleep also decreases levels of your fat-regulating hormone leptin while increasing the hunger hormone ghrelin. The resulting increase in hunger and appetite can easily lead to overeating and weight gain.
So as you can imagine, disruptions to sleep tend to cascade outward throughoutyour entire body.
There’s a lot we still don’t know, but increasingly more that wedo.
For example, poor or insufficient sleep was found to be the strongest
predictor for pain in adults over 50.5
Separate research also found that when participants cut their sleep from 7.5 to 6.5 hours a night, there were increases in the expression of genes associated with inflammation, immune excitability, diabetes, cancer risk, and stress.6
From the results of this study, it appears as though sleeping for an extra hour, if you’re getting less than seven hours of sleep a night, may be a simple way to boost your health. But the opposite also holds true in that getting just one hourless sleep a night may raise your risk of multiple chronic diseases. Interrupted or impaired sleep can also:
- Increase your risk of heart disease and cancer
- Harm your brain by halting new neuron production. Sleep deprivation can increase levels of corticosterone (a stress hormone), resulting in fewer new brain cells being created in your hippocampus
- Contribute to a pre-diabetic, insulin-resistant state, making you feel hungry even if you’ve already eaten, which can lead to weight gain
- Contribute to premature aging by interfering with your growth hormone production, normally released by your pituitary gland during deep sleep (and during certain types of exercise, such as high-intensity interval training)
- Increase your risk of dying from any cause
Your circadian rhythm is very sensitive to changes, such that even the small amount of sleep deprivation caused by Daylight Saving Time may be problematic. One Washington University neuroscientist told CBS News
that adjusting clocks forward one hour corresponds with a significant increase in traffic accidents and heart attacks7
over the next two to three days.8
One study also found that the spring transition, which causes a phase advance
, is particularly hard on the average person’s sleep-wake cycle,9
and while it’s generally thought that the loss of one hour of sleep on the night of the change is inconsequential, research suggests otherwise. According to a report in Sleep Medicine Reviews
“…data suggests that increased sleep fragmentation and sleep latency present a cumulative effect of sleep loss [following the spring transition], at least across the following week, perhaps longer.
The autumn transition is often popularized as a gain of 1 h[our] of sleep but there is little evidence of extra sleep on that night. The cumulative effect of five consecutive days of earlier rise times following the autumn change again suggests a net loss of sleep across the week. Indirect evidence of an increase in traffic accident rates, and change in health and regulatory behaviors which may be related to sleep disruption suggest that adjustment to daylight saving time is neither immediate nor without consequence.”
Case in point, research also shows that Daylight Saving Time lead to increases in workplace injuries (frequency and severity)11
as well as delays in reaction time that affect performance.12
The latter study pointed out that small shifts in circadian timing occur all the time
, not only due to Daylight Saving Time but also to changes such as sleeping in on a Saturday. The researchers concluded:
“These results add to previous reports that suggest that humans may be sensitive to commonly occurring small shifts in circadian timing.”
If adjusting your sleep-wake cycle by one hour twice a year for Daylight Saving Time, or simply sleeping in over the weekend, can disrupt your health, then imagine what traveling through different time zones or working the night shift can do. In one study published in Proceedings of the National Academy of Sciences (PNAS)
, researchers changed the participants’ sleep patterns so they were about 12 hours out of sync in order to simulate the effects of jet lag or working the night shift.13
When blood tests were given, the results showed abnormally decreased gene expression, with up to one-third of participants’ genes measurably altered by the disrupted sleep cycles.
Such disruptions have already been linked to heart disease, obesity, diabetes, cancer, and other chronic health conditions, raising serious concerns for people who regularly sleep during the day and/or stay awake at night. This includes not only those working the night shift but also frequent travelers (jet lag), college students, regular daytime nappers, and late night owls.
The problem is that, in the 21st century, many people ignore their body’s internal clocks, either by necessity (working the night shift or remotely with co-workers across the globe) or choice (staying up late surfing the Web or watching TV). The quandary has some asking whether we should switch to a global Greenwich Mean Time, allowing everyone to honor their body’s clock but have one universal world time.
For the latter to work, economist Steve Hanke from Johns Hopkins University explained to CNN
, everyone would “read the same time on their watches” but you might rise in the morning at 11 am instead of 6.14
Already, people are pushing the limits of their body clocks, getting up early and staying up late for a myriad of reasons. These reasons, it turns out, may not be worth it when it comes to your long-term health. As Dr. Gari Clifford, who studies sleep disorders at Emory University, told CNN
“The more important question is not ‘Should we merge the current time zones?’ but ‘What time should we be encouraging people to get up in relation to sunrise and sunset and how can we discourage exposure to artificial light in the evenings?’ Many of us are guilty of trying to pack too much into the day at both ends, but we suffer for it in the long term.”