Sleep and its impact on brain function and metabolism

Habits to Healthy Blog Post 5

“Sleep is for the weak” basically sums up our fast-paced culture. There’s too much to do in a day… work projects, family life, children to take care of, pets to walk, food to prepare, dishes to clean… Who needs sleep anyway?

Evolutionarily speaking, our body REQUIRES sleep to function. Not just sleep, but restorative sleep.

A 2018 study published in the Journal of Science showed that restorative sleep has a critical function in ensuring metabolic homeostasis. Sleep deprivation has been shown to increase amyloid-beta protein levels (neurotoxic waste associated with Alzheimer’s), sometimes up to 30%. One function of the glymphatic system, the brain’s self-cleaning mechanism, is to remove neurotoxic waste. During sleep, the interstitial space can increase more than 60%, allowing the glymphatic system to “flush” and eliminate waste products more efficiently. So the more sleep there is, the more flushing that can occur.

What happens when there’s a lack of sleep most nights of the week? Our body tries to tell us to get some rest. Some symptoms include:

– fatigue
– brain fog
– irritability
– anxiety
– forgetfulness
– lack of motivation
– depressed mood
– increased appetite or cravings for carbs

These symptoms may be common, but they aren’t normal. It’s not normal to feel so tired that a few cups of coffee are required to function. An occasional coffee can be a tasty treat but is it something our body requires to be at it’s optimal health? It sure doesn’t remove neurotoxic waste like sleep does! 

Poor sleep is a major contributing factor in chronic illness because it disrupts our circadian rhythm. Over time, poor sleep leads to impaired immune function, hormone imbalances, weight gain & diabetes, and increased risk of cardiovascular disease, dementia, and Alzheimer’s.

From a health perspective, the optimal amount for restorative sleep is between 7-9 hours a night. Taking the first step is getting to bed earlier. How many hours of sleep do you typically get a night?

A small study published in the American Journal of Clinical Nutrition found that subjects with 5.5 hours of sleep consumed more calories per day from snacking than subjects with 8+ hours of sleep. Subjects with poor sleep consumed more carbohydrate-heavy snacks than their counterparts.

Consequences of poor sleep are real. It impacts various organ systems, including MANY hormone pathways. One pathway is how sleep affects our brain and eating patterns.

What are hormones? To simplify things, they are signaling molecules (or messengers) that help our body communicate between cells, tissues, and organs.

Leptin is a hormone that tells our brain “I’m not hungry.”

Ghrelin is a hormone that tells our brain “I’m starving! We need food/energy.”

Before meals, ghrelin rises to signal our brain to feel hungry. During meals, as ghrelin starts to decrease, leptin starts to increase. This tells our brain that we’re getting full and to stop eating.

When our body is sleep deprived or not getting enough restorative sleep, it can disrupt the hormone balance between leptin and ghrelin. Levels of ghrelin spike and increase while levels of leptin fall.

Evolutionarily speaking, this makes sense. During prehistoric times, it’s speculated that poor sleep typically occurred during stressful times such as famine or imminent danger. Poor sleep and high stress push our body in fight or flight mode, requiring more energy. What is the quickest and more favorable energy source from food? Carbohydrates!

If getting 7+ hours of sleep isn’t realistic to your routine (or if there’s a lot of stress), that’s okay. Knowledge is power.

The next step to consider may be to keep healthier snack options on hand rather than prepackaged, processed, high sugar foods. Great whole food options are:

-nuts & seeds
-fruit with nut butters
-veggies with hummus or guac
-yogurt

Every. step. counts. Progress over perfection. You got this.

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