How Sleep Impacts Weight Health and Muscle Mass

By Todd Norwood, PT, DPT

This edition covers:

• How sleep influences body composition
• Lack of sleep and sleep disorders
• Sleep tips to improve weight health

Diet and exercise are the top two factors many consider when managing weight. Rightfully so, as the combination of diet and exercise has a strong influence on our overall energy balance.  But there’s a third modifiable behavior that flies under the radar, yet is arguably the most important conduit to weight health: sleep.

The impact of sleep on weight and body composition is perhaps as surprising as it is significant. The weekly recommended amount of sleep for optimal health exceeds the weekly time recommended for physical activity by a wide margin — 49 to 63 hours of sleep compared to just two and a half hours of exercise. This disparity begs the question:

The Relationship Between Sleep and Body Composition

Sleep can influence our body composition when we are losing weight. A 2010 study demonstrated that individuals in negative energy balance lost 60% more muscle mass and 55% less fat mass when only allowed to sleep for five and a half hours each night over a two-week period. This was compared to a group who was allowed to sleep eight and a half hours each night for the same period.

One reason for this finding may be that lack of sleep shifts the balance of muscle protein synthesis and muscle protein breakdown in favor of the latter, which ultimately leads to the loss of muscle mass. It is believed that processes essential to the maintenance of muscle mass occur during sleep, and thus a reduction of sleep impairs these processes.

Recommended Sleep vs. Reality

Adults need at least seven hours of sleep each night, on average, but each individual is different. Some will do well with seven hours, while others may need nine or more hours of sleep to function at their best. However, one-third of U.S. adults report getting less than seven hours of sleep each night.

Lack of sleep can result in fatigue and drowsiness in the near term, but may lead to more profound health consequences in the long term, such as increased risk for obesity, diabetes, high blood pressure, heart disease, and stroke. Reductions in sleep quantity and quality can arise for a multitude of reasons. Some are lifestyle factors such as the consumption of caffeinated beverages late in the day, while others are related to our stage of life such as pregnancy, welcoming a new child, and menopause.

Other reasons one may not attain the recommended amount of sleep each night are sleep disorders, which affect an estimated 50 to 70 million individuals in the U.S. The most common sleep disorder is insomnia, however, the second most prevalent sleep disorder is obstructive sleep apnea (OSA) — a condition linked to higher BMI.

It is believed that between 10 to 30% of U.S. adults struggle with OSA, but many are undiagnosed. The disruptions in sleep caused by OSA are linked to a higher risk of diverse health issues, including depression, nonalcoholic fatty liver disease, and anesthesia-related complications, among others.

Further, U.S. adults report losing almost one hour of sleep each night due to pain, with 56% of individuals attributing it to back pain. Interestingly, the relationship between sleep and pain is a two-way street in which reductions in sleep can increase the perception of pain, and pain can cause insomnia. This highlights the importance of musculoskeletal (MSK) health in both sleep and weight management.

Tips for improving sleep:

• Avoid eating two to three hours before going to bed: Research indicates that eating a meal within two hours of sleep is associated with trouble falling and staying asleep, and over time, may cause obesity. However, if a snack is needed before bed, nuts and seeds are a smart option — people who ate nuts and seeds before bed reported sleeping 30 more minutes per night than those who consumed salty or sugary snacks.

• Stay consistent: When using an alarm, set it to the same time every day, including weekends. Waking up at a consistent time each day helps the body develop a consistent sleeping pattern.  Similarly, going to bed at the same time each night helps to establish a good sleep routine.
• Limit caffeine later in the day: Caffeine is found in a variety of common beverages such as coffee, tea and soda. It can increase alertness and help us feel less tired later in the day, but when we consume caffeine later in the day it can also make it more difficult for us to fall asleep. Limiting or eliminating caffeine after 2PM can make it easier to fall asleep at bedtime
• Be thoughtful about alcohol: Even a small amount of alcohol before bed, as little as two drinks for men and one drink for women, can decrease quality of sleep by 24%. This is the result of how alcohol impacts the brain, which leads toward lighter, lower quality sleep. Avoiding alcohol three hours before sleep is recommended to avoid its impact on sleep quality.
• Exercise regularly: Regular exercise impacts energy use and body temperature, which can promote better sleep. However, intense exercise immediately before bed may make it harder to fall asleep, initially due to elevated heart rate, body temperature and increases in adrenalin. Lower intensity aerobic or resistance training in the evening may facilitate better sleep.

• Minimize use of electronic devices: Using computers, tablets and mobile phones before bed can impact sleep by diminishing the production of melatonin, a hormone that helps prepare the brain for sleep.

When it comes to achieving and maintaining a healthy weight, sleep should be considered a key pillar to success, along with diet and exercise. At Omada, we support our members in achieving their best health outcomes with a multifaceted approach to weight maintenance, integrating evidence and best practices around diet, aerobic and resistance exercise, sleep, and physical therapy for those experiencing musculoskeletal pain.