Sleep has long been recognized as a key factor in the body’s recovery, affecting cognitive function and overall health. One widely accepted view was that during sleep the brain removes toxins accumulated during the day. However, recent studies have challenged this theory, suggesting that the brain’s cleansing process may proceed differently than previously thought. 

Traditional view of the role of sleep 

Earlier studies indicated that the glymphatic system, responsible for removing harmful substances from the brain, gets activated during deep sleep. This mechanism was compared to turning on the dishwasher before bed to wake up with a “clean” brain in the morning. Norepinephrine, a neurotransmitter, was said to play a key role in this process, causing the rhythmic pulsing of blood vessels and promoting the flow of cerebrospinal fluid. Studies in mice have suggested that some sleep drugs, such as zolpidem, may interfere with this process, weakening norepinephrine waves and reducing the efficiency of brain clearance. 

New findings challenge previous assumptions 

A recent study by researchers at Imperial College London sheds new light on the issue. In experiments on mice, they have observed that during sleep the brain’s ability to remove toxins not only does not increase but actually decreases. Using a fluorescent dye, the researchers found that the rate at which this substance passed through the brain decreased by about 30% in sleeping mice and by 50% in anesthetized mice, compared to awake rodents. These results suggest that the brain’s clearance process may be more active during wakefulness than sleep. 

The findings challenge previous beliefs about the role of sleep in brain detoxification. While sleep remains essential for mental and physical health, the mechanisms of its effects on the brain may be more complex than previously thought. Scientists emphasize the need for further research to better understand how the brain removes toxins and what factors influence this process. This could have important implications for the treatment and prevention of neurodegenerative diseases such as Alzheimer’s. 

While it has traditionally been thought that deep sleep plays a key role in clearing the brain of toxins, recent research suggests that the process may be more complicated. Understanding the true role of sleep in brain detoxification requires further research, which may contribute to the development of new strategies to improve neurological health. 

Sources: Dziennik Naukowy, Instytut Gość Media