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Clear your brain's 'metabolic trash' with exercise for restorative sleep

If you find yourself stumbling groggily out of bed each morning despite clocking in a full eight hours of sleep, your body may be trying to tell you something. Poor sleep wreaks havoc on your body in invisible ways.

While chasing more sleep seems like the obvious solution, new research reveals the key to feeling refreshed and well-rested may actually lie in how you spend your waking hours.

Poor Sleep Leads to 'Metabolic Trash' Buildup

"'Sleeping well' may refer to objective measurements of sleep based on the brain's electrical activity during sleep cycles, which include light sleep, deep sleep, and REM โ€” or dream โ€” sleep," Dr. John Saito, a spokesperson for the American Academy of Sleep Medicine (AASM), told The Epoch Times.

If any part of the sleep cycle is disturbed or absent, sleep doctors will objectively consider it poor-quality sleep, he noted.

To emphasize the need for every aspect of the sleep cycle, Dr. Saito compared the process of restorative sleep to running a washing machine.

"How long it takes to complete a wash load depends on multiple variables, including the load size, the water level, and the machine's capacity," he said. "Therefore, it's no surprise that it may take a longer amount of time and multiple cycles to completely clean a heavily stained jacket compared to a lightly soiled undergarment."

If the brain's cleaning process (which occurs during sleep) is shortened, it cannot effectively remove all the metabolic waste products that accumulate during waking hours, according to Dr. Saito. This leads to an accumulation of toxic metabolic byproducts in the brain. Consequently, physiological symptoms associated with insufficient sleep or sleep deprivation arise due to the buildup of these harmful waste materials that the brain cannot adequately clear.

Accumulated metabolic waste refers to byproducts produced during cellular metabolism that the body needs to eliminate. These waste products include carbon dioxide, urea, ammonia, and lactic acid. If not properly removed, they can build up in tissues and organs, potentially leading to health issues.

"Similarly to the washing machine, sleep is the optimal time to clear the brain's metabolic waste products that have accumulated during wakefulness and a time to rest and restore the brain and body," Dr. Salto said.

Fragmented Sleep as Bad as Half a Night's Rest: Expert

It's important to realize that we must get enough good-quality sleep to function optimally, Dr. Thomas Kilkenny, director of the Institute of Sleep Medicine at Staten Island University Hospital, told The Epoch Times.

"A lot of 'bad sleep' does us no good," he said. Certain conditions like obstructive sleep apnea can fragment and decrease sleep's restorative function. "Eight hours of fragmented sleep may be equivalent to four hours of good sleep," he noted, pointing out that it's easy for a "sleep debt" to accumulate.

Sleep debt is the accumulated sleep deficiency that results when a person routinely fails to get the amount or quality of sleep their body requires. This lack of sufficient sleep can have various negative effects on the body and overall health, including reduced immune function, impaired physical and cognitive function, and increased risk of chronic diseases.

"We should realize that the durations of these periods cannot be looked at in isolation," Dr. Kilkenny said. Lengthening the time spent on one activity means shortening the time for another, so striking the right balance across all activities is crucial for high-quality sleep.

For Better Sleep Quality, Exercise Trumps More Sleep Time

If feeling unrested in the morning is common, increasing physical activity may offer a solution.

Typically, sleep specialists recommend a list of "sleep hygiene" protocols for people trying to get a good night's sleep. This list includes recommendations such as avoiding eating before sleep, steering clear of stimulation before bedtime, keeping the bedroom cool, and winding down in a dimly lit room before trying to sleep.

"These rules are highly effective," Dr. Kilkenny said. However, "we must realize that sleep cannot be thought of as a separate entity from the rest of the day." Instead, we should understand that sleep is part of a 24-hour cycle, and "multiple interactions" exist between daytime activity and the quality of our sleep, he said.

A recent study published in Sleep Health examined the sleep patterns of more than 1,100 children and nearly 1,400 adults. Researchers found that those who engaged in higher levels of moderate to vigorous physical activity experienced better sleep quality, reduced tiredness, and fewer sleep disturbances.

The study also found that simply making more time for sleep did not necessarily lead to a more restful night. However, increased physical activity was positively linked to improved sleep quality for both children and adults.

According to Dr. Kilkenny, new additions to the sleep hygiene list should include:
  • Limiting the amount of time spent in bed compared to actual sleep duration: "Spending 10 hours in bed but sleeping only seven will bring about poor quality of that sleep," he said.
  • Focusing on moderate to vigorous exercise: "This type of activity has been shown to be associated with the release of serotonin that improves mood and shows sleep-promoting properties," Dr. Kilkenny said. However, he cautioned against exercise near bedtime.
The benefits of exercise also extend to improved brain metabolism during sleep, Dr. Saito said.

"This study supports my belief that daily physical activity and exercise may not only reduce the metabolic waste load in the brain but also improve its capacity to detoxify during sleep," he said.