We are all guilty of the occasional joke about foregoing sleep to pull an all-nighter or the involuntary sacrifice of sleep because the day got away from us, or we just cannot unwind enough to relax into sleep. But does sleep deprivation really matter? Or is it something that can be fixed with a couple of cups of strong coffee? This blog post takes a look at this underrated issue. If you struggle with weight loss or insulin resistance, or you feel like you are always hungry, it is time to look at sleep quality.
Poor Sleep At-A-Glance
- Poor sleep increases your appetite for high-calorie comfort foods, contributes to weight gain, and raises your risk of insulin resistance and diabetes.
- Reason #1: Temperature: Too Hot/Too Cold. Solution: The sweet spot for bedroom temperature falls between 60°F and 68°F (15.5 to 20°C).
- Reason #2: Eating Too Close to Bedtime. Solution: Stop eating three hours before bed and limit caffeine consumption to the morning hours.
- Reason #3: Intense Evening Exercise. Solution: Complete intense workouts at least three hours before going to bed.
- Reason #4: Excess Lighting. Solution: Make your bedroom as dark as possible and use blue-light-blocking glasses when viewing electronic screens in the evening.
- Reason #5: Excess Noise. Solution: Drown out the sound using a fan, a white noise machine, or a sleep meditation.
- Reason #6: Inconsistent Bedtime/Wake Time. Solution: Develop a sleep routine by going to bed and waking up on a consistent schedule that does not vary more than 30 minutes day-to-day.
Poor Sleep, Weight Gain, Appetite, and Insulin Resistance: Their Link and What to Do [Video]
In this video, you’ll learn…
- How poor sleep affects your health.
- Six reasons why you might not be sleeping well.
- How to boost your metabolism with better sleep.
Does Poor Sleep Really Matter?
There is a saying that you don’t know what you’ve got till it’s gone. The flip side of that is that you don’t know what you’re missing till you find it. Sleep is like that. It is one of the most glossed-over aspects of healthy living because it’s hard to connect the dots between how your body functions and how well you sleep at night.
Poor sleep can leave you feeling tired throughout the day, but that is just the tip of the iceberg. It also increases your appetite for high-calorie comfort foods and contributes to insulin resistance, a factor that makes weight loss difficult and increases your risk of diabetes.
In this post, I share common reasons for poor sleep quality and how they lead to these metabolic issues. I will also share solutions you can implement tonight for better sleep.
Reasons for Poor Sleep Quality
When it comes to sleep, there’s quantity and quality. Both are important, but they are not the same. If you toss and turn in bed for eight hours, you technically meet the requirement for sufficient sleep quantity but achieve poor sleep quality.
Some diagnosed sleep disorders, such as insomnia, restless legs syndrome, and sleep apnea, require a consultation with your doctor. And stress and anxiety can make it difficult to fall asleep because your mind doesn’t want to shut off. However, the most common reasons for poor sleep are an uncomfortable environment and poor sleep habits.
Reason #1: Temperature: Too Hot /Too Cold
The first thing many of us think about in terms of sleep environment is the temperature of the room. Temperature is very much a Goldilocks and the Three Bears issue. Some like it hot, some cold, but for most of us, there is a just-right temperature. And when you do find your optimal sleep temperature, it can result in more deep sleep, fewer wake-ups, and more restorative rest.
Your body follows a circadian rhythm that adjusts your internal temperature throughout the night. To sleep well, your body temperature must drop as you fall asleep and move into deep sleep. This is why most people find it easier to fall asleep in a colder room. The cool temperature helps the body cool down enough to reach that deep sleep level.
Solution: While I found differing study results, the sweet spot for bedroom temperature seemed to fall between 60°F and 68°F (15.5 to 20°C). That is, at least, to fall asleep.
Remember that circadian rhythm is the internal clock that helps you keep your wake/sleep cycle on track. So that rhythm is changing your body temperature all night long, lowering it to achieve deep sleep, and then raising it in the morning to help you wake up.
The challenge is that most bedroom thermostats or beds don’t automatically change to accommodate your body’s temperature fluctuations. And if you sleep with a partner who likes the room warm and cozy but you like it chilly, there is a conflict. A good approach is to set the bedroom temperature to 65°F (18.3°C) as a starting point. From there, you and your partner can adjust it up or down to find a common ground.
Reason #2: Eating Too Close to Bedtime
The timing of your food intake influences your body temperature as you prepare for sleep. When food is in your system, your body shuttles blood flow to your digestive tract. This increased activity elevates your core temperature, interfering with sleep.
Solution: Stop eating three hours before bed, and make your last meal of the day a light one so your body has time to complete digestion and cool down.
You can drink non-caloric beverages during those evenings, but avoid those with caffeine, including coffee, diet soda, and energy drinks. The half-life of caffeine is about six hours, meaning that six hours after you consume it, half of the caffeine is still in your system. Therefore, it is best to limit caffeinated drinks to the morning hours so you can properly wind down at bedtime.
Reason #3: Intense Evening Exercise
As for exercising in the evening, light to moderate-intensity exercise that is completed at least one hour before bed can help you sleep. This would include yoga, stretching, walking, and light weightlifting or light aerobic exercise, such as swimming or biking.
But intense exercise, like interval training, running, or heavy lifting, can overstimulate your nervous system and raise your heart rate and body temperature too much, interfering with sleep.
Solution: If the evening hours are the best time for you to exercise, aim to complete light workouts at least one hour before bed and intense workouts at least three hours before you go to sleep.
Reason #4: Excess Lighting – Room Lighting and Blue Light
Excess light coming in from streetlights or sunlight can disrupt sleep. As can blue light, which is light emitted from the screen of your smartphone, tablet, and computer. Blue light has shorter wavelengths and higher energy than other colors, and exposure to it, especially right before bed, can disrupt the circadian rhythm, making it hard to fall asleep and get restful sleep (1) (2).
Solution: Think of your bedroom as a cave, making it as dark as possible by closing window blinds or curtains. Also, avoid electronic screens at least one hour before bed. There are relatively inexpensive glasses that block blue light. You can pick them up online or in stores. These blue-light-blocking glasses do work. For the best results, wear them three hours before going to bed.
Reason #5: Excess Noise
Noise from outside traffic or inside noise from music, television, or buzzing or beeping gadgets can interfere with sleep.
Solution: Eliminate background noise as much as possible. If it is out of your control, use a fan, white noise machine, or a sleep meditation to drown out the sound and help you relax from a stressful day. There are inexpensive white noise machines that you can buy or online recordings that provide soothing sounds to fall asleep to.
Reason #6: Inconsistent Bedtime/Wake Time
You can train your body for better sleep by maintaining a consistent sleep schedule.
This study shows that shorter sleep duration and greater sleep variability are associated with increased body mass index (BMI) (3).
Solution: Develop a sleep routine by going to bed and waking up on a consistent schedule that does not vary more than 30 minutes day-to-day. You also want to stay in bed long enough. The definition of long enough varies depending on your source, with some defining short sleep as under 5 hours and others under 7. So, from a quantity standpoint, aim for at least 7 hours of sleep (4) (5).
Doing these things strengthens your circadian rhythm. To further reinforce this natural rhythm, it is beneficial to fall asleep within 30 minutes of crawling in bed. So, it pays to go to bed tired. A good way to ensure that is to avoid daytime napping or limit naps to no more than 20 minutes.
The sleep duration and variability studies could not create a direct association between inconsistent sleep patterns and a higher body mass index. However, it is one more supportive finding showing that sleep quality matters to your metabolism.
Why Is Quality Sleep Important to Metabolism
What is clear when we look at poor sleep and weight gain is that sleep deprivation increases your appetite and promotes overeating.
Increased Appetite and Overeating
One study on sleep-deprived individuals used functional MRI scans to monitor changes in areas of the brain that drive our appetite and help us evaluate what we want to eat. They focused on the amygdala, which is a small part of your brain that processes emotions like anger, fear, and sadness and also strongly governs your motivation to eat. They found that the activity within the amygdala is elevated following sleep loss. Also, they found less activity in cortical regions of the brain that help us properly evaluate our need for food, lowering our inhibition to just eat.
And what do we want to eat when we are sleep-deprived? The study authors reported that:
“sleep deprivation resulted in a significant increase in the proportion of “wanted” food items carrying high-caloric content. In contrast, no corresponding differences between the sleep rested and deprived states were observed for low calorie items.”
In other words, study participants weren’t craving carrots. They wanted carrot cake. And they ate the comfort foods they wanted. In the sleep-deprived condition, the participants ate an average of 600 additional calories (6).
It’s easy to see how the desire to eat more comfort foods when we are sleep-deprived is linked to weight gain. But the picture gets bigger when we take a broader look at metabolism, specifically glucose (blood sugar) regulation.
Problems with Glucose Regulation (Insulin Resistance)
Studies have looked at the cascade of negative consequences that occur as a result of sleep loss. Altered glucose metabolism is a broad term that encompasses insulin resistance, where your cells resist insulin’s attempts to drop off glucose. This resistance keeps blood sugar and insulin levels high, making it hard to lose fat and increasing your risk of diabetes (5).
Considering how many people have trouble losing weight, the prevalence of diabetes and insulin resistance, and the fact that around 30% of adults report sleeping less than 6 hours per night, it’s clear that sleep quality matters (4).
To improve your sleep, limit caffeine consumption to the morning hours and avoid eating three hours before bed. Also, avoid intense exercise at least three hours before bed and work on developing a consistent sleep schedule where you get into and out of bed at a similar time each day.
And, importantly, work on making your bedroom environment conducive to sleep by covering windows, limiting computer and phone screen usage, using soothing sounds to block environmental noise, and dialing in the right temperature for high-quality sleep by setting your bedroom temp between 60 and 68°F.
Thank you for reading and have a wonderful week!
(1) Holzman, David C. “What’s in a color? The unique human health effects of blue light.” (2010): A22-A27.
(2) Duffy, Jeanne F., and Charles A. Czeisler. “Effect of light on human circadian physiology.” Sleep medicine clinics 4.2 (2009): 165-177.
(3) Jaiswal, Stuti J., et al. “Association of sleep duration and variability with body mass index: sleep measurements in a large US population of wearable sensor users.” JAMA internal medicine 180.12 (2020): 1694-1696.
(4) Sharma, Sunil, and Mani Kavuru. “Sleep and metabolism: an overview.” International journal of endocrinology 2010 (2010).
(5) Knutson, Kristen L., et al. “The metabolic consequences of sleep deprivation.” Sleep medicine reviews 11.3 (2007): 163-178.
(6) Greer, Stephanie M., Andrea N. Goldstein, and Matthew P. Walker. “The impact of sleep deprivation on food desire in the human brain.” Nature communications 4.1 (2013): 2259.