14 Jan The Timing of Sleep
We are excited to have our friend and colleague Jena Fraser, RMT, write a guest blog on the timing of sleep. Sleep is an important part of health and recovery – one that is often overlooked or ignored. Read on below to understand the importance of the timing of sleep.
I was asked to write a blog on something that I am very interested in: SLEEP. This is a complex and not fully understood state of being that we spend approximately 27 years of our life. There are many areas of sleep science that are being studied; many different theories on what happens during sleep that makes it an important human condition, so today I’m choosing to begin our sleep education with the timing of sleep. I’m going to challenge your understanding of how your brain and body work; to educate you on why learning about the timing of sleep will allow you to make educated decisions that affect your health and longevity rather than being ignorant, sick, tired, injured and thinking that it is due to genes, old age, or fate.
Our health and longevity are linked to the subtle nuances our environment has on our body that we may not even sense.
I am going to discuss sleep biology and the cycle of daylight/night time effect on the body, the hormonal cascades that happen during sleep that will affect your recovery of daily activities, why sleep is coupled to your metabolism, and how to get better sleep. Most importantly, at the end of this article you will understand WHY it is so important to adhere to proper timing of sleep.
What is the optimal number of hours of sleep to get? 6hrs? 7hrs? 8 hrs? Is napping beneficial? The amount of sleep isn’t meaningful if the timing is off. At the wrong time of day, sleep is inadequate and inefficient. Two keys for optimal timing of sleep:
- maximum concentration of melatonin (4 hrs of dark needed prior)
- minimum core body temp (6 hrs of sleep needed prior)
What needs to happen for these two keys of optimal timing of sleep?
Melatonin: “Darkness Hormone”
Melatonin, a hormone, is the third most important anti-oxidant in the brain. It is made from a conversion of seratonin from the gut – this takes four hours. It is signaled to be made by photopigments called melanopsin in our cells in the eyes by the loss of blue (and green) wavelengths of light. Melatonin is part of a hormone axis with leptin and cortisol. Low levels of melatonin are linked with epithelial cancers, such a breast cancer. Watch this great episode of David Suzuki’s The Nature of Things on CBC linking the two: http://www.cbc.ca/natureofthings/episodes/lights-out
6-7pm: The sun sets.
Dim light, loss of blue wave lengths of light, signals melanopsin to signal seratonin to begin to convert to melatonin.
If you watch TV, use your computer, check Facebook on your iPhone, play Candy Crush on your iPad, have all the lights on in your house: you will not make melatonin.
Blue light blocks melatonin conversion.
7pm: Insulin falls.
There is a rise in leptin. Leptin is a hormone that is released from fat cells, which regulates body weight by decreasing food intake, increasing energy expenditure, and inhibiting fatty acid synthesis via different hormonal cascades. It tells the brain how much fat there is stored in the body to burn as fuel, and how much inflammation is in the brain.
Insulin and leptin are coupled.
If you eat, even one little bite (your “sleepytime” tea, a celery stick, swallowing your sweet toothpaste) this raises your insulin and blocks leptin release.
10 pm: Melatonin is secreted (after being converted for the last four hours in darkness/dim light).
There is also a drop in core body temperature that happens in conjunction to the secretion of melatonin. The release in leptin is increased.
Adenosin, a chemical end product of ATP (energy from calories) which signals the body to be sleepy, peaks, causing you to fall asleep. Side note: caffeine attaches to the receptor for adenosin, blocking the feeling of sleepiness. So, no coffee later than 2 pm for proper sleep timing.
12 – 3 am: This is the most CRITICAL TIME!
These three hours are responsible for autophagy, the process of rebuilding proteins and recycling cellular contents. First, at 12 am, melatonin allows leptin to enter the hypothalamus to signal hypocretin neurons to enter cycles 3 (delta waves) and 4 (REM) of our sleep cycles . This also tells the thyroid to become more efficient and raises our basal metabolic rate. We burn fat. Also, at midnight, leptin tells the hypothalamus to release prolactin. This prolactin surge is very important, it signals the largest amount of human growth hormone! If there is no prolactin surge, meaning if we eat after 7 pm, or if we see blue light after the sun goes down, you will have a higher body fat percentage and a lower muscle mass percentage. This lack of prolactin surge will immediately screw up the most effective anti-oxidant in the brain: DHEA. When DHEA is low, it allows other hormones to “open” the gut, making it permeable, otherwise known as “leaky gut”. (And who has leaky gut? People with autoimmune disease – a whole other topic!)
2 am – 6 am: Lowest core temperature
During this time, we experience our lowest core body temperature, needed for specific changes in the brain during autophagy, which is a whole other discussion for another blog post.
6am: Cortisol surge
Our cortisol surges to wake us up and signals gherlin to surge, which makes us hungry. Morning sunlight hits our retina, shutting off melatonin secretion, which takes about an hour.
BEST TIMES DURING THE DAY: (if sleep times adhered to)
- 10 am – highest alertness
- 2:30 pm – best muscle coordination
- 3:30 pm – fastest reaction times
- 5 pm – greatest cardiovascular efficiency and best rates of protein systhesis (i.e.: best times for Coach AA to have a metabolic class!!)
Timing is the most important part of sleep to allow for functional hormone cascades to heal injuries, build new muscle, have a proper menstrual cycle, be alert, and have ideal body composition.
Sleep Timing Guidelines
- No eating 4 hours before bedtime.
- As the sun sets, don’t use blue or green wavelength sources of light. No artificial light. Wear “blueblocker glasses” – no peeking!
- No caffeine after 2 pm.
- Cool environmental temperature in your bedroom.
- Expose your eyes/body to natural light first thing in the morning.
- Eat a large meal within 30 mins of waking.
Jena Fraser is a practicing Registered Massage Therapist and Rehabilitative Specialist. Her foundational values for treatment and rehabilitation stem from the model of Regional Interdependence – “a concept that seemingly unrelated impairments in a remote anatomical region may contribute to, or be associated with, the patient’s primary complaint”. Using this model, Jena enjoys working with patients who want to be their best in daily activities, hobbies and sports while learning about proper recovery, injury prevention and how to move more efficiently. Since graduating, she has worked with provincial, national and professional level athletes return to competition after injury but her love is working with elite level youth athletes. Jena’s passion for the processes of the brain and hormone systems stem from a curiosity of how the tissue she treats, repairs and functions optimally. Follow Jena on Facebook (https://www.facebook.com/jena.rmt) , Twitter (https://twitter.com/jenafraserrmt) and Instagram (http://instagram.com/jenafraserrmt) www.jenafraserrmt.com