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How Digestion and Fasting Impact Sleep Quality and Consistency

After maintaining a regular fitness routine, eating a healthy diet is one of the most common lifestyle suggestions for improving health. While what you take in to fuel your body is important, so is how your body breaks it down and uses it. As a result, proper digestion is essential to overall wellness and should be made a priority.

The digestive system breaks different foods down into chemical building blocks that can be used by cells and tissues throughout the body. Proteins, carbohydrates, and fats are the three main macronutrients found in food. Through mechanical and chemical digestion, they are broken down into amino acids, simple sugars, and fatty acids and glycerol, respectively. These components can then be absorbed and put to use. 

Many vital physiological processes require the interactions of multiple organ systems, and digestion is no exception. The digestive tract works with several other systems to break down and distribute nutrients. The muscular system helps break food into smaller parts. Muscles are involved in each step of the digestive process, from those in the tongue and mouth that assist with swallowing and send food into the throat, where muscle contractions help food travel through the esophagus into the stomach. 

In the stomach, muscles create churning movements that force the food particles to come into contact with digestive acids and enzymes. Muscle contractions move food further along the digestive tract into the small intestine. The circulatory system helps transport nutrients around the body. After food particles are absorbed in the small intestine, they enter the bloodstream and are carried to cells or tissues in need. 

The respiratory and circulatory systems work together to direct blood flow to the digestive system after food consumption, meeting the increased demand of oxygen for digestion and absorption to occur. These systems also work together with the excretory system to remove waste products created from digestion from the large intestine.

The nervous system also plays a crucial role in digestion. Digestion is one of the automatic physiological processes controlled by the parasympathetic branch of the autonomic nervous system.

During periods of rest, the parasympathetic nervous system increases digestion rate, sends energy to the digestive tract, and stimulates insulin release to assist in the breakdown of food into glucose — an energy source that can readily be used by cells. The nervous and endocrine systems work together to control feelings of hunger and satiety, and the release of chemicals involved in digestion.

Digestion is a complex process that involves cooperation between many different organ systems. Proper digestion, and the successful interaction between these systems, can be promoted by optimizing eating habits. Irregular eating habits can have a negative impact not only on health as a whole, but on sleep quality and consistency specifically. Find out more about the relationship between digestion and sleep.

Why Sleep Quality and Consistency Matter

In addition to focusing on diet and exercise, getting enough sleep is another popular tip for leading a healthy lifestyle. The benefits of prioritizing sleep duration, quality, and consistency have been backed up by research. According to the NIH, adults should aim to get between 7 and 9 hours of sleep each night. Research has found that sleeping from 7-8 hours nightly is associated with optimal health outcomes. 

Regularly getting less sleep than recommended by experts has been linked to the development of health conditions including heart disease, obesity, diabetes, dementia, and certain cancers. Poor sleep also leads to reduced cognitive function and difficulty performing activities like work, driving the car, exercise, and other hobbies.

Sleep duration is not the only important factor in optimizing health. Sleep quality, or how well you sleep, is also vital. Even if you sleep for 7 or 9 hours a night, it’s possible to wake up feeling tired and not well-rested. This is an example of poor sleep quality.

Poor sleep quality has a negative impact on both physical and mental health. It’s associated with high blood pressure, high cholesterol, impaired functioning of the immune system, a greater risk of developing Alzheimer’s disease, and symptoms of anxiety and depression.

Another key aspect of sleep is consistency, which involves maintaining a consistent sleep schedule and routine. This entails going to bed and waking up at the same time each day. WHOOP research has found that better sleep consistency contributes to increased time spent in restorative REM and slow wave sleep, reduced resting heart rate, increased heart rate variability or HRV, and improvements in mental health. Sleep consistency helps the body maintain its natural circadian rhythm, and also benefits sleep quality and efficiency. 

How Digestion Impacts Our Sleep

Typically, there is reduced digestive function at night during sleep. Food is not being taken in, so there is less work to do in breaking down food particles. The primary focus of the digestive tract during sleep is tissue growth and repair. The digestive system is able to rest and heal at night, preparing for the busy day ahead. 

Eating before bed, however, can lead to disruptions in the relationship between digestion and sleep. Activity increases in the digestive tract to digest the food, spurring activity in related organ systems including the muscular, respiratory, excretory, and circulatory systems.

The body is forced to devote energy and resources to support the digestive process instead of focusing on promoting sleep. This makes it difficult for the body to enter into a restful state, leading to trouble falling and staying asleep, lowered sleep duration, and decreased sleep quality.

WHOOP data supports the negative relationship between eating before bed and sleep. When WHOOP members ate close to bedtime, they averaged a 26 minute reduction in typical sleep duration and a 3% decrease in REM sleep, which supports mental restoration. Late meals were also associated with a 10% drop in next-day recovery scores. Late eating times can negatively impact sleep duration and quality, and the body’s ability to recover and get ready to start off the day and perform.

Health conditions that involve the digestive system can also make getting enough good quality sleep more difficult. Symptoms related to GERD and indigestion can make falling and staying asleep uncomfortable, cause coughing that interrupts sleep, and can be worsened by lying down. Constipation is associated with decreased sleep duration, IBS has been linked to difficulty sleeping, and individuals with Crohn’s Disease commonly have poor sleep.

6 Tips For Improving Eating Habits For Better Rest

Taking steps to promote healthy digestion can lead to improvements in sleep quality, duration, and consistency. There are many simple lifestyle changes that can be made to eating habits to help achieve this goal. These are a few tips to help improve digestion and sleep:

Limit Nighttime Eating

One of the most important ways to prevent digestion from interrupting your sleep is to limit food intake before bed. Experts recommend avoiding eating at least 2-3 hours before going to sleep. Individuals who avoid late meals are also less likely to deal with uncomfortable digestive symptoms, such as heartburn and indigestion, at night.

Avoid Trigger Foods

Certain foods are more likely to cause stomach pain and discomfort during sleep, and should be avoided later in the day to prevent sleep disruptions. For example, spicy foods are known to cause acid reflux, and fatty or high-protein foods often cause a feeling of fullness that can make sleeping more difficult. Individuals with known digestive issues such as IBS, Crohn’s, and GERD should also avoid consuming foods that are known to trigger and exacerbate the symptoms of their conditions. 

Make Smart Snack Choices

Improving eating habits is not just about avoiding certain foods that can trigger digestive discomfort — it can also involve adding foods to your diet that promote proper digestion and sleep. If you are hungry before bed, choose a small snack that will help you fall asleep. For example, almonds, turkey, kiwi, walnuts, and carbs like white rice, oatmeal, or toast are sleep-promoting food options, while chamomile tea, tart cherry juice, and passionflower tea are good beverages to try.

Try Intermittent Fasting

Intermittent fasting is a practice that involves only eating during a set window of time each day. Typically, individuals will determine an 8 hour block of time, such as 8 a.m. to 4 p.m., and only eat during that time. Intermittent fasting has many benefits, including improved cognitive function, elevated mood, and improved sleep. Individuals who practice intermittent fasting often report experiencing more restful sleep and increased feelings of alertness during the day. It has been theorized that fasting benefits sleep by supporting the body’s circadian rhythm. 

Reduce Caffeine and Alcohol Intake

Caffeine and alcohol are two more substances that can keep you up at night and should be limited in the evening hours. Caffeine is a stimulant, and has been found to decrease sleep quality and duration, decrease time spent in restorative deep sleep, and make falling asleep take longer. Alcohol commonly causes more nighttime awakenings and makes staying asleep difficult. It also typically makes sleep feel less restful, and can worsen symptoms of obstructive sleep apnea, a sleep condition that causes periodic airway blockages and disrupts sleep.

Schedule Meals

While going to sleep and waking up at the same time on a daily basis can improve sleep consistency, applying the same principle to eating meals can also benefit sleep. Scheduling meals for specific times each day is another way to promote your circadian rhythm and help keep the body in homeostasis so that key physiological processes, including digestion, can be performed normally. Maintaining a routine with your meals can also help control appetite and prevent the urge to snack or eat meals late at night.

Track Sleep with WHOOP

WHOOP is beneficial in tracking sleep in several different ways. With in-depth sleep monitoring, WHOOP tracks nightly sleep duration and records time spent in each of the 4 sleep stages. WHOOP also monitors how much sleep you need, factoring in sleep debt, any recent strain, and recent naps to give a daily calculation of how much sleep you should aim for each night. In addition, WHOOP records your sleep performance, including wake events, disturbances, sleep efficiency, and respiratory rate.

Track your sleep with WHOOP as you try out tips to improve your eating habits and get personalized, up-to-date insight into how they benefit your sleep quality and consistency.