We kicked off Week 1 of our Monthly Focus: Sleep with a Life Without Limits podcast, featuring sleep expert Dr. Amy Bender. This week, we dive into our scientific and biological need for sleep, below.
It’s the one thing every person on the planet can do each day to repair and reset their health. It’s not a drug, it’s not an activity, it’s not even a food. It’s sleep. And it is perhaps one of the most important—and simultaneously untapped—aspects of overall wellbeing.
Despite years of clinical research, we still don’t completely understand why we need to sleep. What we do know—from lived, human experience—is that sleep is a life support system.
The Daily Deep Clean
Recent sleep research shows that while we sleep, our brains are busy at work flushing out cellular waste. There could be a potential link between sleep and neurodegenerative diseases, like Alzheimer’s disease.
The sleeping brain uses up almost as much energy as the awake brain; the once deeply-held belief that sleep served as a natural mechanism for energy conservation is now deemed unlikely.
Instead, it’s during this time of sleep that the body clears out all the toxins that accumulated as a result of daily thinking. While awake, neurons are constantly at work firing off synapses, which means an increased demand for energy and cellular supply.
Once we sleep, though, the neurons finally catch a break and turn off, allowing for the first time in a 24-hour timespan for a deep self-clean. It’s during this imperative cleaning process that cerebrospinal fluid—working in correlation with the glymphatic system—collects, transports, and removes metabolic and protein wastes each day from the brain.
Lack of sleep (or, sleep deprivation), then, affects this deep-cleaning process. Without it, chemicals in the brain aren’t restored to their proper levels; instead, we remain in a deficit state, causing emotional and mental handicaps to cognitive function, behavior, and judgment the very next day.
The Great Metabolic Healer
It’s not just a daily cleanup that we get when we sleep. Sleep regulates metabolic health and function. There is mounting evidence that insufficient sleep contributes to the pathogenesis of metabolic disorders, CVD, and cancer, among other chronic conditions. At a time when metabolic dysfunction is rampant worldwide, we could all benefit from more sleep.
During the day, the body is focused on getting things done rather than repairing itself. But when we sleep, energy expenditure is fully devoted to mending the body. One of the most important aspects of the recovery process is restoring metabolic homeostasis.
There’s a one-to-one relationship between sleep and metabolic activity. Sleep, for example, controls not just the amount of food we eat, but what we eat. Our desire for food (part of the reward center in our brain) is more pronounced with less sleep. We crave high caloric foods (high fat, high sugar) that contribute to a negative metabolic profile.
This is the problem we’re seeing on the surface. But what’s really happening to the metabolic system here?
Insufficient sleep has direct effects on satiety hormones, insulin and glucose regulation, and the neuro-processing center.
The right amount of sleep keeps our satiety hormones in balance, among others. Leptin suppresses hunger, while grehlin increases it. With optimized sleep levels, these energy-balancing hormones are in perfect balance. But when sleep deprivation occurs, there’s a significant reduction in leptin (full signaling) and an increase in grehlin (hunger signaling). These hormone levels are disrupted without proper sleep, causing increased appetite and food consumption.
There’s also consistent evidence that sleep deprivation results in impaired glucose tolerance and decreased insulin sensitivity. If you currently rely on exogenous insulin to stabilize blood sugars, you may have noticed you need more insulin after sleepless nights. But it’s not just for people with diabetes: whole-body insulin sensitivity is lower when sleep is impaired, for anyone.
Insulin sensitivity decreases by 25%, which results in (but could also be in addition to) a 23% reduction in glucose tolerance, or higher blood sugars.
The Power of a Good Night’s Slumber
Adequate sleep—7-9 hours in a night—restores the body. This naturally recurring state, characterized by altered consciousness, relative inhibition of bodily functions, and reduced interactions with surroundings pulls the body out of its energy deficit and into a replenished state.
It makes just about everything in your system go right; it is critical to making the most of the time you’re awake.
Don’t miss out on one of the easiest—and best—ways to optimize your health. In our next post on this month’s focus, we'll debunk some of the most common sleep myths out there.