The significance of good sleep is so meaningful that one could easily argue it is the most important factor in achieving a healthy and fit body. We spend over a third of our lives sleeping. If you are so lucky (or unlucky depending on your perspective) to live to be a nonagenarian you’ll have spent approximately 30 years asleep. It’s such a substantial part of life, interconnected to virtually every part of one’s health, yet why we need to sleep remains a medical mystery. William Dement, the founder of Stanford University Sleep Center, stated: “As far as I know, the only reason we need to sleep that is really, really solid is that we get sleepy.” Laboratory animals subjected to extreme sleep deprivation die rather quickly of a confluence of unknown causes. Sleep deprivation is a faster killer than starvation. We can’t live without sleep. Every organism on this planet with a central nervous system and brain requires regular sleep. We can go ahead and add sleep to the list of primal core needs every human requires to sustain life (food, air, water, shelter, and sleep). Being so significant and crucial to life, one would think the science of sleep would be more understood. Nope. Here is what we do know regarding the functions of sleep:
Getting some zzz’s instigates a heightened anabolic state during which the body rejuvenates and grows. Human growth hormone released during sleep assists in fat burning and muscle building.
Sleep helps with the processing of memories and cognitive functions.
It allows us to dream. Although we are not sure why we dream. The most accepted theory posits ‘we dream to help our memory, to sort through and store experiences, to “clean out” the unneeded information in our brains, among other things’.
Our sleep cycles are governed by the circadian rhythm. This is an internal 24-hour clock residing in every cell of your body responsible for overall alertness. It coincides very closely with the sun’s schedule. For most of human history, we slept in 2 distinct stages. Before the electric light bulb was invented, most people went to sleep shortly after nightfall and woke up 4 to 5 hours later. They would stay up and do various things (sex mostly) for about an hour before going back to bed for their ‘second sleep’. Sometime around sunrise, they’d wake up refreshed and ready for the day. Adult humans need roughly 1 hour of sleep for every hour they are awake – about 7-9 hours per night (teenagers and kids need more sleep). How much you sleep on a regular basis has a huge impact on your weight, diet choices, cognitive ability, emotions and even disease rates. Exposure to artificial light and the ability to travel quickly through time zones (a la jet setting) have unfortunately befuddled our internal clocks and screwed up our sleep.
Sleep Factoids:
Science has no answer as to why we need to sleep. Although we know it is vital, sleep seemingly goes against every survival instinct. While we are dreaming away we are not getting food, protecting ourselves and/or procreating (sleepwalking experiences excluded). Many animals sleep with only half their brain ‘off’ (unihemispheric slow-wave sleep) for fear of predators.
Randy Gardner, in 1965, stayed awake for 11 days – a world record. During this time he experienced delusions, paranoia, cognitive deficits, and aggressiveness – he basically turned into a pseudo-zombie.
After pulling an ‘all-nighter’ blood pressure will elevate, metabolism will go down, body temp drops, the immune system gets weaker and many people claim to get uncontrollable cravings for carbohydrates.
Sleep has 5 stages that cycle over roughly 90-100 minute periods.
During REM sleep you release hormones to effectively paralyze your limbs so you don’t act out your dreams.
Overexposure to night light (specifically LEDs, LCDs and fluorescent lights) has been linked to cardiovascular disease, diabetes, obesity, and cancer.
Sleep deprivation is linked to signs of “skin aging and slower recovery from a variety of environmental stressors.”
Sporting teams and athletes that play in their own time zone during periods of circadian boosts (9 AM till 2 PM & 6 PM till 10 PM) are a lot more likely to win – it is called the circadian advantage.
About 1-3% of the population (short-sleepers) have a mutated gene that allows them to function normally on less than 6 hours of sleep.
Memory has been shown to be enhanced by sleep. “Several studies have shown how sleep facilitates long-term memory processing, both the conversion of short-term memories into long-term ones and also the reconsolidation of existing long-term memories.”
Working late into the evening under a light that is bright enough to “read a book by” will confuse your circadian rhythms and lower your blood level of melatonin (the sleep hormone). These lower levels of melatonin will affect the body’s production of estrogen, human growth hormone, and testosterone. Not good. Chronically putting yourself in this position (i.e. working the overnight shift at 7-11) will weaken your immune system and put you at higher risk for many cancers and other diseases. Fluorescent bulbs, LCD and LED lights (in your computer, TV, phone screens and digital clocks) emit the most deleterious light because they radiate a higher level of blue on the spectrum.
“Light at night is bad for your health, and exposure to blue light emitted by electronics and energy-efficient light bulbs may be especially so….Harvard researchers and their colleagues conducted an experiment comparing the effects of 6.5 hours of exposure to blue light to exposure to green light of comparable brightness. The blue light suppressed melatonin for about twice as long as the green light and shifted circadian rhythms by twice as much (3 hours vs. 1.5 hours).” – Harvard Sleep Center
Even light as bright as a small table lamp can interfere with an individual’s circadian rhythm and melatonin secretion. Turning down all your lights and electronics at least 60 minutes prior to bedtime will help you sleep better. Using lights that are warmer on the spectrum (with less or no blue light) has been shown to have a minimal but quantifiable effect. If you can’t turn off the TV or computer, purchase filters to place over the screen to block the blue light. Perhaps the best option is to read a boring book under an old fashioned incandescent bulb set to dim. My outdated “Clinical Neurology of the Older Adult” is sure to put you to sleep.
Sleep and Weight Loss
Sleep, arguably, is just as important in helping one achieve health and fitness goals as diet and exercise. Mountains of medical and research evidence suggest compelling links between sleep and weight. The quality and duration of your sleep may “silently orchestrate a symphony of hormonal activity tied to your appetite“. Four major hormones responsible for appetite and weight control (leptin, ghrelin, cortisol, and insulin) are all negatively affected by a lack of good sleep. Studies show if you don’t get enough sleep your body will store more food as fat, increase your appetite, and decrease your sensitivity to insulin. It’s a double whammy: lack of proper sleep increases your hunger while reducing your ability to feel sated. To top it all off, the foods your body craves when sleep-deprived are typically higher in sugar and more likely to be stored as belly fat (in some)! Furthermore, access to food is increased within the hours you stay awake – when you should be sleeping. Cognition and mental clarity are reduced when you have not slept enough. Thus your ability to make complex decisions is suppressed. Good luck fighting off the desire to eat food you would normally avoid. Lack of sleep zaps willpower.
Sleeping increases the anabolic state, which promotes growth hormone release, protein synthesis, fat oxidation and muscle growth. Chronic sleep deprivation increases catabolism and makes it nearly impossible to lose weight and put on lean muscle mass. If you are working hard in the gym and watching your diet don’t ruin all of your arduous work by not getting enough sleep. Sleeping 7-9 hours per night is probably the easiest thing you can do for your health and body.
NOTE: If you sleep 5 hours or less per night you will have a 50% increased chance of becoming obese.
Lesser Known Sleep Tips:
Studies report most people sleep better in rooms 60-68 degrees Fahrenheit
Rid yourself of evening blue light exposure (TV, computer, bright clock, and fluorescent and LED bulbs) or turn it all off at least 1 hour before bedtime
If you work late under blue light spectrum bulbs, wear blue light blocking sunglasses
Got to bed earlier to get more in rhythm with your natural sleep cycles (and get up soon after the sun rises)
Have a consistent sleep schedule where you wake up and go to sleep at the same time every day….even on weekends
Sharing a bed with a spouse, child or pet (especially snakes and rodents) makes good sleep more difficult
Getting adequate exposure to natural light during the day (especially the morning) will help regulate your circadian rhythm
Have trouble falling asleep? Check out this site with effective techniques to help: Sleepingtricks.com
More Sources:
1. Randall, David. Dreamland: Adventures in the Strange Science of Sleep; W.W. Norton & Co. 2012. 2. Harvard’s Sleep Center 3. Stanford’s Center for Human Sleep Research 4. TED Talk: Russell Foster – Why do we sleep?
Doug Joachim – NYC Personal Trainer www.JoachimsTraining.com
