We live in a sleep deprived society. Although experts recommend that adults get seven to nine hours of sleep a night, nearly a third follow these guidelines.
For some of us, spending so much time between the sheets can seem impossible. Whether you work the night shift, have a new baby who's up all the time, stay up late studying, or have trouble falling asleep due to stress, you can go days, weeks, or even months without getting a good night's rest.
For others, sleeping for just five or six hours is their modus operandi. Maybe you're feeling fine and don't think you need more sleep, or maybe your schedule is packed to the brim and spending an hour or two more on the pillow isn't a priority.
Negative effects of not sleeping properly
After less than seven hours of sleep, you may notice that you yawn more than usual or have a short fuse. But hey, it's not the end of the world, is it? The truth is that many of the health problems that can arise from skimping on sleep do not present themselves as immediate cause and effect.
Insufficient sleep wears out your health engine sooner, but it may take many years before you can begin to see medically significant symptoms. People who are sleep deprived also tend to develop clinical medical problems later in life, as years of sleep inefficiency catch up with them.
Let's say that after a lifetime of sleeping five hours a night you have a heart attack.
Although laboratory results indicate that the heart attack was the cause of death, researchers are beginning to connect the dots about how not getting enough sleep increased the inflammation and atherosclerosis that contributed to the heart attack. Or if you died of cancer, the reason you had a higher risk of disease was because your immune system was not working at its best due to lack of sleep.
In other words, if you are not getting enough sleep right now but you are not suffering, that does not mean that you are safe. Rather, your bad dream may not have caught up with you yet.
While getting too little sleep is not the smoking gun connection, and some people who sleep little do not suffer negative health consequences, science holds that seven to nine hours is best for most people.
It is also important to note that there is a link between health problems and sleeping too much . According to Johns Hopkins Medicine, sleeping more than nine hours is associated with type 2 diabetes, heart disease, obesity, depression, and mortality.
What can happen if you need more sleep?
First of all, don't worry if you occasionally stay up late hanging out with friends, or if you have a sleepless night here or there when you're sick or jet lagged. One night of sleep deprivation is no big deal. Our bodies can always bear some deviation from the ideal.
But interrupting your sleep regularly does come at a price. Here are some of the health risks related to lack of sleep.
Obesity
An October 2018 review, published in BMJ Open Sport & Exercise Medicine, found that people who habitually slept less than seven hours a night were more likely to have a higher BMI and be obese.
When you don't get enough sleep, your body reduces the release of leptin, a hormone that helps suppress your appetite and encourages your body to use energy.
Researchers also found that too little sleep increases levels of the hormone ghrelin, which stimulates appetite and can lead to weight gain. In addition, they note that people who do not spend a lot of time in bed have less energy for physical activity during the day. And obesity puts you at higher risk for sleep disorders, which perpetuates the problem.
Diabetes
A November 2016 study published in the Oman Medical Journal found an association between poor sleep and type 2 diabetes.
Sleep-deprived middle-aged and older people are twice as likely to be diagnosed with type 2 diabetes as well-rested people. That's because sleep helps regulate glucose and metabolism. Lack of sleep also leads to an increase in cortisol, which can make cells more resistant to insulin.
Heart disease
Insufficient sleep contributes to atherosclerosis, a build-up of plaque within your arteries that can restrict blood flow and lead to heart disease, according to a January 2019 study in the Journal of the American College of Cardiology.
Meanwhile, a July 2020 study in Psychosomatic Medicine found that people who spend minimal time sleeping also have higher blood pressure . Over time, this leads to more plaque that blocks the coronary arteries.
So it's no surprise that a September 2019 study from the Journal of the American College of Cardiology revealed that people who sleep little have a 20 percent increased risk of heart attack.
Compromised immunity
In a September 2015 study in Sleep, people who slept six hours a night or less were four times more likely to get a cold. In fact, the researchers determined that sleep was the greatest predictor of illness, more influential than age, stress level, race, education, income or being a smoker.
Lack of sleep reduces the production and release of cytokines, a versatile protein that helps the immune system respond to threats. When you are sleep deprived, your body cannot act as fast or send as much cytokine to counteract any problems you may have.
Lack of sleep can not only increase your chance of getting sick after being exposed to a virus, but it can also prolong the time it takes you to recover from the illness.
Reduced cognitive function
In the short term, skimping on sleep affects your ability to focus, retain information, and synthesize new ideas ; you are also more likely to make mistakes. When you sleep less than six hours, your reaction time slows down by 30 percent and gets exponentially worse the less you sleep.
That's because your brain undergoes a major recharging process when unconscious. During deep sleep, your neurons and the cells in your cortex fire and then deactivate in a pattern we call slow waves. This slow wave movement allows cerebrospinal fluid to seep into the cortex and flush out toxins that build up in the brain.
If you reduce your deep sleep, these toxins are not removed properly. As a result, your thinking will not be as sharp the next day. Additionally, according to an April 2018 report from the NIH, one of the toxic proteins shed during deep sleep is associated with Alzheimer's disease.
Bad mood
Not getting enough sleep can lead to irritability and anxiety. Your ability to properly regulate stress hormones is undermined and your cortisol levels rise.
Lack of sleep can also affect your social and family life. It affects our emotional reserve and adds to interpersonal problems. When we are sleep-deprived and our cortex, the thinking part of the brain, is not well rested, we cannot control the most primitive parts of the brain.
In other words, you are more likely to regret it, get defensive, and make poor decisions , which is a recipe for difficult relationships.
How many hours of sleep do you really need?
The dream is not unique to everyone; how much you need depends on your age, lifestyle, and genetics. From birth to 18 to 20 years, we go through a neurodevelopmental process and need more than seven to nine hours of sleep.
Older people tend to need less sleep at night because they nap during the day.
Your menstrual cycle can also influence your sleep – women may need more rest before and during their period. Pregnant women and high performance athletes should also spend more time under the covers.
But for most of us, our ideal sleep time comes down to DNA. It is genetically determined based on your chronotype or biological clock. It varies from person to person, so you may feel energized after seven hours of sleep, while your partner is in a bad mood if they sleep less than eight. The idea that everyone needs eight hours of sleep is a myth: sleep is personalized.
In an October 2019 study in Science Translational Medicine, researchers identified a "short sleep" gene . People with this genetic mutation can go without effect for only four to six hours without negative side effects. However, this variant is incredibly rare, affecting only half a percent of the population.
But what about people who claim they only need five hours of sleep and feel good in the morning? Consider this a wake-up call. There is also a survival mechanism in your brain that tells you to get over tiredness, even if you are sleep deprived, so you could be springing into action. So you should probably go to sleep earlier.
Use this formula to determine the right amount of sleep for you
Most people go through five sleep cycles each night. Each cycle lasts between 80 and 120 minutes, with an average duration of 90 minutes. Since it takes the average person 7.5 hours to go through five 90-minute sleep cycles, ideally use 7.5 hours at your initial sleep set point.
Now, take your normal wake-up time and go back 7.5 hours. Make that your bedtime. For example, if you need to get up at 6:30 am, you should go to bed at 11:00 pm Stick to this bedtime for 10 days. If, after 10 days, you wake up without an alarm clock and feel refreshed, then you have identified the right amount of sleep for you.
If you still need an alarm to wake up, it may indicate that your sleep cycles are longer than 90 minutes. Increase your bedtime by half an hour and after 10 days check if you wake up naturally. Continue experimenting in 10-day intervals until you reach your ideal bedtime.
If you still feel sluggish in the morning after sleeping for nine hours, it could indicate a sleep disorder or a medical condition that prevents you from getting adequate rest. In that case, it is a good idea to speak with a doctor.
Is it really bad to sleep less than the recommended amount?
The answer lies in how much sleep you personally need, and how much less than what you are actually getting. As long as you feel good, I don't think it's a bad thing. Does anyone remember the last time they slept 7 hours?
But if you sleep less than your body and brain need to recover and restart, that's a different story. For example, if you calculate that you need seven hours of sleep and you only sleep five, this is bad enough. And if you feel bad, it's a red flag.
Still, it is not always obvious when you are too tired. Not only can caffeine trick you into thinking you've had enough rest, but eventually feeling sluggish will become your new normal and you won't realize that you're not as alert as you could be.
Science has revealed that by not getting enough sleep, we are reducing the opportunity to achieve our best health trajectory throughout our life.
