The role of sleep in health and disease is gaining more attention as the science continues to advance our understanding of the interplay between the two. Sleep is something we value at MHS, not only as individuals, but as an important area of research as a whole.
But first, let’s start with the basics: Why is sleep so important for our health?
Despite what it seems like, sleep is not just a passive event that takes place every night. There is quite a lot of activity that goes on during sleep, as we cycle through the different stages of sleep, each playing their own unique role. The two primary types of sleep are rapid eye movement (REM) sleep and non-REM or deep sleep, where learning and memory, and physical growth and repair dominate, respectively.
The gymphatic system
A good night’s rest has been shown to play an important role in immune system support, learning and memory consolidation, balancing appetite regulating hormones (e.g. ghrelin and leptin), muscle growth and repair, stress reduction, among others. So, it seems logical that a lack of sleep could impair the ability to fulfill these duties, and thus lead to health issues. In fact, chronic sleep loss has been associated with mental disorders (e.g. depression, anxiety), neurodegeneration, immune system impairments/deficiencies, inflammation, and weight gain, among various other ailments. Sleep is our body’s time to recover from wakefulness, both physically and mentally, bringing the body back into balance.
Sleep is the brain’s chance to clean up and recover from a hard day of work. Part of our brain’s immune system is called the glymphatic system, and we’re going to explore this important topic!
When we sleep, the glymphatic system jumps into action and clears the brain of waste and toxic proteins have accumulated throughout the day, discarding them through its own waste collection service outside of the brain.
When we lose sleep, we miss out on this crucial opportunity to eliminate unwanted build up in the brain since the glymphatic system is relatively dormant while we are awake. Almost like missing garbage day, and having your trash will sit around until the next scheduled pick-up. This offers a possible explanation for why chronic sleep loss is associated with increased risk for cognitive decline, because the glymphatic system clears the brain of the type of toxic proteins that can contribute to neurodegenerative disease like Alzheimer’s.
The science of sleep continues to hint at its importance in the prevention of cognitive decline, and the glymphatic system appears to be a critical piece to the puzzle.
What influence our sleep system ?
14 March is World Sleep Day, an annual event intended to be a celebration of sleep and a call to action on important issues related to sleep, including medicine, education, and social aspects. In honor of this important day of awareness, we’d like to explore what influences our sleep cycles .
Humans function on circadian rhythms, with light having the strongest influence on our sleep cycles. Once upon a time, this was controlled by the cycles of the sun, but nowadays we have the addition of indoor lighting playing its part too. This intrinsic circadian clock also controls various factors that influence sleep, for example:
- Body temperature – begins to fall before bed, and begins to rise upon waking
- Heart rate – drops in the evening, reaching its lowest point around mid-sleep, and rises during the latter half of the night
- Melatonin secretion – Rises in the evening (in the absence of blue light), peaking mid-sleep, and falls during the second half of the night
- Cortisol levels – Slowly rises as we sleep, peaking within the first hour of waking
- Adenosine levels – Builds up during wakefulness, peaking around bedtime, and declining during sleep
These cycles occur every day, with light exposure and other lifestyle factors influencing them, consequently enhancing or impairing sleep.
Tips for better sleep
we want to leave you with some tips for better sleep.
1. Avoid caffeine in the late afternoon
Caffeine blocks the action of adenosine. Adenosine builds up during the day and increases our desire to sleep. Caffeine is metabolized slowly, so avoiding it in the late afternoons is typically recommended to avoid its interference with sleep.
2. Avoid activities that elevate heart rate before bed (alcohol, a heavy meal, exercise)
Alcohol, night-time eating, and exercise can all increase body temperature and heart rate, sending the wrong signals to the body that you’re getting ready to sleep. If you’ve ever eaten a heavy meal late at night, you’ll know exactly what we are talking about, because processing food isn’t exactly a restful state for the body.
3. Sleep on a consistent schedule
Your body will learn when it’s bedtime and when it’s time to wake up by managing your circadian rhythms with a consistent sleep schedule.
4. Avoid blue light exposure in the evening
Light has the largest influence on our circadian rhythm, and from an evolutionary perspective signals to the body that it’s day time. Blue light suppresses the production of the sleep hormone melatonin. Once the sun has set, limit how many lights are on in your house and avoid screens. Also consider using blue-light filters on your devices or wear blue-light blocking glasses as some research suggests these can improve sleep quality in certain individuals.
