For most of us, sleep is something that happens at some point during the day. It's when we're unable to effectively function anymore and tell ourselves it's time to shut down. The time we allocate for sleep is usually whatever time we have left over at the end of the day. It can very easily become a last priority but bottom line, we cannot be healthy and happy without it. For this reason, we get to take ownership and prioritize our sleep. We get to be intentional as to when we go to sleep so that we are getting the amount of hours we need as well as the quality sleep our body needs to function.
Let's consider our energy expenditure on the day or the amount of energy we exert across 24hrs. There are 5 things that play into this and they are, basal metabolic rate, resting metabolic rate, non- exercise activity thermogenesis, exercise activity, and the thermic effect of food. I'm going to speak on, "basal metabolic rate" or BMR as this is the largest contributor to our energy output on the day. According to Precision Nutrition, BMR accounts for up to 75% of the total energy across the day in sedentary individuals and up to 60% in physically active people. So, what does this have to do with sleep? Great question! First, lets take a quick look at what BMR is.
Imagine you are laying in bed and you're asleep. You haven't eaten in a while and therefore, there is no digestive activity going on within your body. You're breathing, your heart is beating, and your cells are doing the bare minimum to keep you alive. You are not moving or doing much else. The amount of energy you expend in this state is what is considered your BMR. Isn't that crazy!? Between 60-75% of the energy we expend every day comes from non-movement related physiological activity. Why is this? To provide an example, if you are awake for 16hrs a day, absolutely everything you did during those 16hrs, your body will recover from during the 8 hrs you are asleep. This is why the energy output while we are asleep or our BMR is so high. If we compare BMR to exercise activity or EA, this accounts for between 10-15% or less for sedentary individuals or 30% or higher in highly physically active individuals. Considering those numbers alone, you can see how if I am looking to lead a healthier lifestyle and look better, feel better, and perform better, quality and quantity sleep is a must. If I simply increase and prioritize weekly exercise, but am not intentional about my sleep, I will not yield the best results possible!
In the previous paragraph, I stated that if I am awake for 16hrs a day, my body will recover from "absolutely everything" I did in those 16hrs during the 8hrs that I am asleep. So what is "everything"?
Sleep restores "everything" in our body which includes our immune, nervous, skeletal, hormonal, and muscular systems. Sleep supports regulation of our metabolism which keeps us lean and healthy, including blood sugar and insulin levels. Eventually, chronically inadequate sleep is linked to gaining fat and risks of diabetes. Finally, sleep helps us to make and recall memories. We think, learn, and make decisions better when well-rested. Healthy adults need at least 7 hours of sleep per night, and sometimes more!
One of the best ways to allow ourselves to get adequate rest each night is to have set bedtimes and wake up times. Our sleep cycles run on timing directed by an internal clock, called our circadian rhythm and this is largely impacted by external cues such as light exposure! In the morning, this isn't so much a problem for many but at night when preparing for bed, artificial lights can mess with our circadian rhythm and negatively impact our ability to fall asleep. The later we go to bed and the shorter our sleep hours, the more likely we are to gain weight over time. And because sleep helps regulate our blood sugar, lack of sleep can actually cause or worsen insulin resistance and type 2 diabetes! As my high school baseball coach used to say, "NG", (No good).
Conversely, an earlier sleep time can also mean less eating, as for many folks, late night is a comforting time for a snack. Let's be real, at 11 p.m., we're not snacking on steamed broccoli lol. So staying in bed can reduce the temptation and being well-rested usually means fewer food cravings and smarter choices the next day. More sleep makes you feel happier and saner. Abnormal circadian rhythms have been associated with depression, bipolar disorder and seasonal affective disorder.
We don't control what happens in our body while we sleep, but we can be intentional with the time leading up to when we go to sleep. Prioritizing sleep is not a magic trick and it requires us to take action!
Are you getting 7-9hrs of sleep each night?
If not, what's one action or process goal you can set for yourself to get there?