The number of people who can survive on 7 hours or less of sleep or less without showing ANY biological or cognitive impairment is actually 0% (when rounded to a whole number).
More than 1/3 of Americans have trouble sleeping every night, and 51% of adults say they have problems sleeping at least a few nights a week.
So that begs the question – how much sleep do we actually need?
This definitely varies, but studies have shown that we need at least 7-9 hours of sleep per night. That is not time in bed either, this is actual sleep. So for us to accomplish the minimum of 7 hours per night of sleep, we would need to be in bed for roughly 7.5-8.5 hours, given that we rarely fall asleep right away, and we rarely stay asleep the entire night.
There is a SMALL percentage of the population that contains a gene called the DEC2 gene. This is a ‘short-sleeping’ gene which essentially allows individuals to survive on slightly less sleep. The percentage of you having this gene is less than the percentage of you getting struck by lightning. And even those that do have these genetic mutation still have shown to need at least 6.25 hours of sleep per night.
So for those of you that think you are ‘fine’ with 5-7 hours of sleep a night, let’s chat a bit about what is truly going on.
A lack of sleep impacts weight in a couple of different ways.
One is through our hormone production of, specifically, leptin and ghrelin. These are our ‘hunger hormones’, as they control feeding, energy regulation, sympathetic nervous system activity, and really all things that influence weight. Studies show that when sleep is restricted, these hormones adjust in a way that make us hungrier and more likely to store body-fat, and less likely to burn energy.
Ghrelin is intended to stimulate hunger. So when there is a lack of food in the system, ghrelin levels rise. Leptin is considered our ‘satiety’ hormone. After we eat, it is released to indicate fullness and no more need for food.
When we are sleep restricted, studies have shown that there is about a 15% increase in ghrelin (hunger level), and about a 15% decrease in leptin (satiation levels). Meaning you are hungrier, and you don’t get full as easily.
The second way weight can be impacted from lack of sleep is by our body’s metabolic adjustment and its ability to regulate glucose.
When we get less sleep, our body is essentially in a heightened stress state. When our body gets into this type of state, it works to conserve energy. This translates to us burning fewer calories, and so after a night of poor sleep, when we normally may burn 2400-2500 calories in a day, now we may only be burning 2200-2300 calories a day, or less. On top of that, our body also shows a pretty immediate and significant impairment on glucose regulation – meaning how we process carbohydrates/sugar.
So chronic sleep deficiencies actually increases your risk of obesity by 55%. Enough of the weight gain fear, what else does sleep impact?
When you sleep, your immune system releases proteins called cytokines. These not only help sleep, but sleep deprivation has shown to decrease the overall production levels of these proteins. They are protective in nature, and they are necessary to increase when you are stressed or need to fight off certain infection or inflammation.
In addition, infection-fighting antibodies and cells are reduced during periods where you don’t get enough sleep.
Lack of proper sleep also impacts our ability to think, handle stress, moderate our emotions, and other typical effects include increased chance of heart disease, hypertension, diabetes, and other psychiatric disorders such as depression and anxiety.
Understand this will not happen overnight (no pun intended). It will take time for your body to adjust to the changes that you are implementing, and start with just one, the easiest one to you, and then build on it.
Our body loves routine. It thrives off of it, starting at infancy, our body searches for consistency in a schedule. Ideally, bed-time should be before 10:30-11 pm each night, no matter when you wake up because that is what our bodies are designed to do. Before the age of technology, we went to bed when the sun went down. Those first couple of hours of sleep are some of the most restorative you will get all night.
So if you are going to bed at 9:30 every night during the week, then staying out until 1 am on Saturday night with friends every weekend, it will be impacting your sleep for multiple days after. Stay consistent, even on the weekends!
Studies have shown that exposure to sunlight and outside light during the day increases melatonin production by up to 50%. So next time you want another cup of coffee, try to go for a 5-10 minute walk outside instead. WE promise you will feel more awake, AND you will most likely sleep better that night.
The more light we are exposed to at night, the more difficult it is for our body to relax and be prepared for sleep. So turn down the lights, or even go by candle-light! Turn the dimmer on your phones, or put your phones away. And try to limit the TV right before bed.
Caffeine’s half-life in our system is about 6-8 hours, so we recommend finishing your caffeine intake by 2 pm each day, if not earlier. Switch to decaf if you need!
Like we said, our body loves routine. So try to have the same routine around the same time each night to help you sleep! Brush teeth, go to the bathroom, get in bed and read or journal for 5-10 minutes with NO TV or Phone around.
If you truly cannot get more than 6 hours of sleep due to work, or whatever the reason is, try to fit in a nap during the afternoon to allow for an accumulation of 8 hours total of sleep.