One thing we all have in common is sleep. We actually spend a majority of our life asleep. The real question is why do we do it? Truth be told, no one actually knows why. However, what we’ve known for a long time is that we need it for the optimal functioning of our body. Modern society has wreaked havoc on our sleep schedules and cycles. From the need to be productive late into the night, to answering emails at 3am, and shift work for some professions, there is less of an emphasis on the importance of sleep. The lack of sleep and fluctuations in our sleep schedules is proving to have many negative health consequences. Proper sleep patterns are an often-overlooked aspect of health that is proving be critical to our overall wellbeing.
WHAT IS SLEEP?
When reading about the science of sleep you may have heard about REM (rapid-eye movement) and NREM (non-rapid eye movement) sleep. The two can’t technically be differentiated, except with imaging looking specifically at eye movement. Throughout the night, you will generally cycle through REM and NREM sleep. Commonly, REM sleep is considered more “active” compared to NREM sleep and more of the physiologic benefits occur during NREM sleep1,2.
While we sleep, there is a DECREASE in:
- Sympathetic tone (causing the body to relax)
- Blood pressure
- Heart rate
- Metabolic rate
- Oxygen consumption
- Glucose turnover (using glucose as energy)
- Skeletal muscle uptake of glucose (since the muscles aren’t active, they don’t need as much fuel from glucose)
While we sleep, there is an INCREASE of the following in the brain:
- Glycogen stores (storing glucose for later use)
- ATP levels (ATP = energy)
- Peptide synthesis
WHY DO WE SLEEP?
We know we don’t function well if we don’t get enough sleep, but there are also health consequences associated with impaired sleep. These consequences range from impaired cognitive function (i.e. you’re not as focused or you’re not able to retain information properly), a possible increase in all-cause illness and disease, poor appetite control and poor glucose control. We’ll look further into some of these concerns below.
SLEEP AND TYPE 2 DIABETES – IS THERE A LINK?
Now that we know how important sleep is for our wellbeing, this review looked deeper into impaired sleep with diabetes, specifically Type 2 diabetes. The authors outlined how a lack of sleep, or a shorter sleep than normal, would lead to Type 2 diabetes and/or impaired glucose tolerance (control of blood sugar). Insulin decreases blood glucose levels in the body after a meal and glucagon increases blood glucose levels when they’re low. Our body strives to maintain a balance for optimal functioning. Even short-term changes in sleep patterns, even as short as a week, can have these negative effects on our health. It was even suggested that Type 2 diabetes could also negatively impact sleep, consequently causing a vicious cycle.
SLEEP, TYPE 2 DIABETES AND INSULIN RESISTANCE
The specific mechanisms of how insulin sensitivity is affected by changes in sleep patterns appear to be quite complex. Several studies suggested that impaired sleep was associated with increase in cortisol and catecholamine levels as well as an activation of the sympathetic nervous system. Additionally, studies have shown that lack of sleep could lead to reduced thyroid stimulating hormone (TSH) and testosterone levels, disrupted growth hormone (GH) secretion, and an increase in pro-inflammatory cytokines.1,3 All of these changes on an endocrine level may lead to impaired insulin signaling.
IS LACK OF SLEEP RELATED TO OBESITY?
As you may have noticed from your own experience, when we don’t get enough sleep we tend to be more hungry than normal. Studies have shown that you aren’t alone. Decreased sleep (compared to normal) can cause an increase in appetite, and therefore an increase in food intake. Sleep and its effects on appetite control may be a key component to consider when determining the best course of action for obesity1,3.
WHAT IS A GIRL TO DO?
If I told you that one simple change could help you to lose that tire of abdominal fat that you are carrying and decrease your cravings, would you do it? Of course you would! Although it sounds too good to be true sleep is that thing!
In an ideal world the most benefit occurs with 7-8 hours of sleep per night. If you are only sleeping 5-6 hours then this may seem crazy! But start slow.
What can you do to get even 15 minutes more sleep tonight?
What if falling to sleep is the issue?
Well I have you covered! Find out more here.
- González-Ortiz, M., Martínez-Abundis, E., Balcázar-Muñoz, B. R. & Pascoe-González, S. Effect of sleep deprivation on insulin sensitivity and cortisol concentration in healthy subjects. Diabetes. Nutr. Metab. 13, 80–3 (2000).
- Colten, H. R., Altevogt, B. M. & Research, I. of M. (US) C. on S. M. and. Sleep Physiology. (2006).
- Mesarwi, O., Polak, J., Jun, J. & Polotsky, V. Y. Sleep disorders and the development of insulin resistance and obesity. Endocrinol. Metab. Clin. North Am. 42, 617–634 (2013).