6 Crazy Facts About Sleep
1. Among people with Alzheimer’s, 60–70 percent have at least one clinical sleep disorder.
The vast majority of Alzheimer’s patients have at least one clinically diagnosed sleep disorder. While correlation is not causation, there does seem to be a strong link between sleep deprivation and Alzheimer's risk, and here’s one of the possible reasons why:
Our brain’s immune system (aka the glymphatic system) is most active at night, clearing away damaged cells, debris, and amyloid beta plaques. In the absence of sleep, these amyloid beta plaques are left to accumulate and, as a consequence, create oxidative stress, damage, and cognitive decline.
Just to be clear, we’re not talking about days, weeks, or even months of sleep deprivation. The human body is resilient and can bounce back from that. We’re talking about years or even decades of chronic sleep loss.
2. Poor sleep and circadian rhythm disruptions increase cancer risk.
In addition to not getting enough sleep, disruptions to your circadian rhythm also damage the immune system and can lead to increased cancer risk. The link is so strong that the World Health Organization classifies night-shift work as being a probable human carcinogen.
In fact, this link is so strong that Denmark actually started paying compensation to women shift workers who developed breast cancer after years of working night hours. Crazy! But also, hats off to them for acknowledging this link!
3. People who sleep just five hours per night are 4.5 times more likely to catch a cold.
Research reveals a striking correlation between sleep duration and susceptibility to catching a cold. People who slept only six hours per night were 4.2 times more likely to catch the common cold than those who slept seven hours nightly, and those who slept five hours a night were 4.5 times more likely to get sick.
For every hour of sleep lost the risk of infection increases, which highlights how sleep deprivation weakens the immune system and makes us more vulnerable to infection when exposed to viruses.
4. Sleep deprivation can cause blood sugar imbalances.
Individuals who sleep less than five hours per night have twice the risk of prediabetes than those who sleep seven hours. And diabetes risks factors such as sleep apnea and shift work can further compound the problem by adversely impacting glucose metabolism.
This is due to the link between poor sleep, insulin resistance, and increased levels of ghrelin, our hunger hormone, the next day. Cravings for carbs and sugar are also higher the next day to boost energy and compensate for feeling tired.
And these effects happen pretty quickly! Even one night of sleep deprivationhas been shown to trigger insulin resistance and blood sugar imbalances in healthy subjects.
Note: A few nights of interrupted sleep isn’t a huge reason for concern — it happens to the best of us! But if this stat is stressing you out, be sure to read the conclusion, which helps to put everything into perspective. 5. Poor sleep increases amygdala activity by a whopping 60 percent!
The amygdala is the emotional control center of the brain responsible for processing dangerous or life-threatening stimuli. However, the amygdala can be influenced by traumatic experiences, leading to overactive responses to nonthreatening situations.
A fascinating study of sleep-deprived participants exposed to emotionally negative images found that their amygdala activity spiked by 60 percent compared to well-rested individuals. Further analysis with brain imaging revealed that the sleep-deprived group displayed disrupted communication between the amygdala and prefrontal cortex, a brain region responsible for moderating the amygdala's response.
This means that poor sleep can mess with our mood the next day, making us more emotional and reactive to triggers that wouldn’t typically bother us. 6. Getting less than six hours of sleep per night is associated with a 200 percent higher risk of heart attack.
The risk for heart attack goes up by approximately 200 percent in individuals sleeping six hours or less per night, according to an NHANES analysis. And it’s not just heart attacks—stroke and congestive heart failure are also higher in those who lack good-quality sleep.
We need to enter the non-rapid eye movement sleep stage for our hearts to recuperate. People who sleep less than six hours or have fragmented sleep can’t get sufficient REM sleep, which impacts recovery and increases the risk of heart problems.
Dr. Suniya (in Dhru P.'s masterclass, please ask me and I will send you the link!) says, “Sleep is one of the most underrated and underappreciated aspects of health,” and I couldn’t agree more. The power of a good night’s sleep for our brain, heart, mood, and immunity can not be overstated.
We all deal with sleep deprivation and fragmented sleep from time to time, myself included. It’s the cumulative effect of sleep loss that can lead to significant health problems. By first recognizing the importance of sleep and the role it plays in whole-body health, we can begin to better prioritize it in our lives. (adapted from Dhru Purohit's newsletter)