Sleep Affects Cognition: How to Stay Sharp and Relieve Brain Fog

Sleep Affects Cognition: How to Stay Sharp and Relieve Brain Fog

How sleep affects the brain? As dawn breaks, our body wakes up ready for the day or the fog rolls in and blinds the way. We take sleep for granted. We go to bed, make ourselves drowsy by reading, fall asleep, and then it is morning. However, results vary for many people. Some people have difficulty in falling asleep; others wake up around 2AM and have a hard time to fall asleep again. Not sticking to a regular bedtime, a heavy dinner was not early enough to allow complete digestion, not winding down in the evening from stressful events, all contribute to disturbing the natural secretion of melatonin in the body and rob it from an energizing restful sleep. Dr Smith’s and Moheet’s et al. articles mentioned below discuss this in detail. When one does not sleep well, the body struggles to be productive the next day with a loss of creativity. While sleep might not come easy for some, it is important to synchronize the body’s chronobiological system and daily habits, to regulate sleep. This practice can positively influence cognitive abilities and a host of other health benefits. We spend half of our lifetime sleeping. Is it not worth optimizing?

Some people might have major problems to fall asleep or to stay asleep. Stress can reverse our cortisol hormone levels from being high in the morning and low in the evening to low in the morning and high in the evening. High cortisol in the evening will compromise melatonin secretion that eventually upsets our sleep.

It is understandable that living life is more exciting than sleeping it away. People are excited about the day, with kids to feed, homework to finish, projects to complete, emails to answer and another movie to watch before the body can dose off and rest for the night. It is not easy to program our activities and others’ around us to zero in on our sleep hygiene, but it is worth the effort.  After all people want to be at their best condition to be able to perform the activities that they desperately seek to accomplish in the day. Most people like sleep, yet no one wants to fall asleep or play a routine to allow it to happen.

Brainlit shows the relationship between sleep and our quality of life from a cognitive perspective. Light affects sleep and sleep affects our brains and cognitive function. Let’s examine the impact of light has on sleep and how this can be used to improve our quality of life. Light has a tremendous effect on our sleep quality, pattern, and time of sleep. It helps regulate our circadian rhythm to tell the body when to sleep and when to be awake. BrainLit’s inventor Tord Wingren, the man behind Bluetooth, has studied how light affects our chronobiology and developed a professional indoor lighting system to mimic the natural light of the sun: warm and mellow in the morning and evening, intense, bright, and bluish at midday, between 10AM and 2PM. Of interest to our topic, he aligned his research with the Nobel prize winners, Jeffrey C. Hall, Michael Rosbash and Michael W. Young, who published their paper in 2017 “for their discoveries of molecular mechanisms controlling the circadian rhythm”. Wingren’s Bio-Centric Lighting System is meant to entrain our biological clocks to improve our sleep pattern and quality. When light hits our eyes, our brain interprets this information in the suprachiasmatic nucleus and uses this information to “synchronize our circadian rhythm with our surroundings”. Anytime we are exposed to light we tell our brain to realign with the current state of light to either keep us alert or to prepare our bodies for sleep.

Identifying the factors that impair sleep helps to address them to optimize sleep.  Dr Michael A. Smith who is a medical advisor with Life Extension, published an article aptly titled: “How many hours of sleep do we need to prevent cognitive decline?” He reviews several references on the topic of sleep, its effects on cognitive decline and Alzheimer’s disease. Dr Smith notes the ‘sweet spot’ between 5.5-7.5 hours of sleep is “essential for a healthy fulfilling life’’. Any less or more than this range could contribute to cognitive decline and lead to the advancement of Alzheimer’s disease and increase the risk of other health concerns, like cardiovascular, diabetes and mortality. Dr Smith states that it is possible to support our sleep with nutrition, physical activity, and food supplements.  In case one simply cannot control their environment to help induce sleep, then they can consider a cocktail of targeted supplements to make them drowsy without having to resort to medication. The mix might need to be modulated for different people. To help one relax, fall asleep and stay asleep one would start by not consuming stimulants like coffee, alcohol, or energy drinks after 4PM. One hour before bedtime one could consider taking the following, 1000 mg of L-Tryptophan with Niacin and L-Lysine, 3 mg of immediate release melatonin, 3 mg of immediate and extended melatonin release, 500 mg of Magnesium, along with an herbal extract of magnolia tree bark, lemon balm, chamomile flower with a special kind of ashwagandha called Shoden. In addition, it is important to time the daily meals to be protein heavy at lunch and a lighter fair at dinner with easier foods to digest like pasta and vegetables.

Proper sleep at the right time and for a certain number of hours allows our bodies to be healthy and not to succumb to diseases. According to an article called “Tick Tock: New Clues About Biological Clocks and Health.” By National Institute of General Health Sciences, our sleep pattern is influenced by our biological clocks that are affected by light. In-sync internal clocks can improve our general health whereas out-of-sync clock-related disorders can range from insomnia to diabetes, depression, cognitive decline, and weight gain. Light can entrain our circadian rhythm to be slow, fast or in sync with a 24-hour cycle. An in-sync circadian rhythm with the light-dark cycle of life helps regulate our sleep and its duration. Cryptochrome is a protein that is responsible for the synchronization of the liver’s production of glucose and is sensitive to the internal clocks that are affected by and reset by fasting at night when one sleeps and when one eats during daylight. According to Moheet and others in their article “Impact of diabetes on cognitive function and brain structure,” both types of diabetes, 1 and 2, are associated with a reduction in performance in the cognitive function and abnormalities in the brain structure. This shows how clock related disorders that affect diabetes and sleep can eventually cause cognitive function decline.

While sleep loss exasperates our mental capability from the first day we do not sleep well, it continues to put a heavy toll on our cognitive function every day we lose sleep and makes the problem exponentially worse. According to an article published last year by the University of South Florida, “All it takes is three consecutive nights of sleep loss to cause your mental and physical well-being to greatly deteriorate.” There is no making sleep up in the weekends. Sleep must be a regular event with a duration of 6 hours or more.

We see that these four independent studies point to the same conclusion: While sleep is influenced by many external factors such as light, daily activities, eating, or fasting and nutrition, sleep can in turn have a large impact on our health and of special interest, our cognitive ability. Sleep period needs to be about 6-7 hours for our bodies to be refreshed in the morning and ready to tackle our mentally challenging day. While it is not easy for everyone to follow such a routine, the rewards are well worth the effort to regulate sleep to prevent cognitive decline and relieve the morning brain fog. Many people still take sleep for granted, yet it is best not to disturb the natural sleeping process with busy daily activities and out of sync routines.



“Elderly Care, The Importance of Lighting for the Elderly.” BrainLit,    2021_compressed.pdf. Accessed 28 Mar. 2022.

Hall, Jeffrey, and Michael Rosbash. The Nobel Prize in Physiology or Medicine 2017, The Nobel Prize, 

“New Study Uncovers How a Series of Sleep Loss Impacts Mental and Physical Wellbeing”, University of South Florida, Science Daily, 6 July 2021,

Smith, Michael A., “How Many Hours of Sleep Do We Need to Prevent Cognitive Decline?” Life Extension, Science & Research, Health News, Accessed 28 Mar. 2022.

“Tick Tock: New Clues About Biological Clocks and Health.” National Institute of General Medical Sciences, 1 Nov. 2012,

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