Metabolic health is a hot topic amongst healthcare professionals. The increase in chatter is for good reason given the alarming statistic that 88% of the American population is displaying at lease some level of metabolic dysfunction. These metabolic dysfunctions underlie most chronic diseases. Learning ways in which we can improve our metabolism can help us to make healthy choices that improve all of the outcomes associated with metabolic health: brain function, energy, memory, mood, skin health, fertility, risk of chronic disease.
Given the growing rate of metabolic dysfunctions in America, researchers have looked beyond the topics of diet and exercise in order to search for ways in which we, as a society, can become healthier. This research has shown sleep to have a substantial impact on metabolism. With most of us reporting to be sleeping significantly less than the recommended amount, we are pushing our bodies beyond their limits. When we push too far we disrupt our: glucose metabolism, leptin/ghrelin production, and orexin secretion; all of which contribute to our metabolic health.
How does sleep impact blood sugar?
When we are short on sleep our glucose metabolism is disrupted. Glucose is the main source of fuel for the brain and powers our short bursts of energy. In the short term, when glucose is disrupted, it can lead to an imbalance in energy levels (like the sleepy feeling after eating a large sugar-heavy meal), lightheadedness, irritability (aka “hangry”), and brain fog. Even a single night of sleep restriction to 4 hours impacts our glucose metabolism in healthy subjects. When we repeatedly get 5 or fewer hours of sleep, we create continuous disruptions in glucose management, and significantly increase our risk of type 2 diabetes. Intuitively, most of us know that we probably should get more sleep. Life gets in the way or we are in the midst of a great Netflix series so we try to “make up” this sleep elsewhere. However, more sleep is not necessarily better either. Individuals who continuously sleep 9 hours or more also have an elevated risk of type 2 diabetes.
Not only does our length of sleep impact glucose, but our stages of sleep also play a role. Deep non-rapid eye movement (NREM sleep (aka slow-wave sleep) is a part of the sleep cycle in which the body undergoes restorative processes. Slow-wave sleep induces hormonal changes throughout sleep that impact glucose regulation. When we have poor quality sleep and do not have enough slow-wave sleep, our glucose tolerance is reduced. This knowledge is especially important for aging obese individuals, as they are populations that have been shown to experience less slow-wave sleep. Thus, finding ways to bolster this part of the sleep cycle could be especially important to improve glucose metabolism and reduce the risk of metabolic conditions.
Leptin (an appetite suppressant) and ghrelin (the ‘hunger hormone’) are two hormones that are significantly impacted by sleep and also play a large role in metabolism. Sleep deprivation has been shown to lower leptin levels and increase ghrelin. This means that we are more likely to feel hungry (even when our bodies do not necessarily need the calories for fuel). It also means that we are less likely to feel that satisfaction that triggers us to stop eating when we are full. This can lead to poor food choices and consuming many more calories than we actually need.
What if we have a night of short sleep?
Luckily, there is a quick way to help ameliorate the effects of sleep deprivation if you are in a crunch. High-intensity interval training (aka HIIT) can offset (for 24 hours) some of the negative effects that sleep deprivation has on glucose metabolism. HIIT is especially effective at improving free fatty acid levels and glycemia. The moral of the story is that if you have a poor night’s sleep, throwing in some HIIT may help you get through the day.
How can we improve our glucose levels?
Since there are many factors that impact blood sugar (food, activity, stress, sleep, etc.) we have multiple options for ways in which we can improve our glucose. In general, foods higher in protein and low in simple carbohydrates (e.g, not candy, starchy, or heavily processed foods) will help to regulate blood sugar (more on this in a future article). By choosing foods with high protein content, we can reduce hunger sensations and avoid the impaired hunger signals sent by leptin and ghrelin when we are sleep deprived. When we are out with friends or unable to control our diet as much as we would like, using a tool like GOOD IDEA can help to reduce the blood sugar spike that would typically come after a high carbohydrate meal. In addition, staying active is a great way to put that glucose to use for fuel and muscle building. Full workouts and/or multiple mini-physical activity breaks throughout the day can boost our sugar utilization and help to achieve the blood sugar stabilization that has been shown to improve our health. When it comes to sleep, consistency is important. Try to have consistent sleep and wake times whenever possible. Making sure we get enough slow-wave sleep can also aid in glucose metabolism. High-intensity exercise (although not right before bed), body heating (aka sauna or hot tub), and short-term low carbohydrate diets are all ways to increase our amount of slow-wave sleep.
Author: Colleen Gulick, Ph.D (ExPhys), MS, BS (BioE), FE (ME), CSCS