“To sleep…perchance to dream…” William Shakespeare
This month we will cover the effects the sleep has on food choices, how it drives our appetite, and how the quality, duration and intensity of our sleep plays a role in our athletic performance.
We all know the importance of getting a good night’s sleep. We know how good we feel once we have had one, and how poorly we feel when we have not. I’m certain that all of us have suffered the consequences of jet-lag at one point in our life, but did not know why our body felt this way. We all know that after a poor night’s sleep our energy levels, our creativity, judgment and reaction times suffer. It is this “dis-synchrony” between our central body clock, entrained by light, and our other organs that are out of synch – we are not designed to be awake for 18 hours per day without consequence. It is estimated that at least 31% of the drivers on the road daily suffer from sleep deprivation, or sleep restriction. This gives way to what is called “micro-sleeps”, those little milliseconds of when we nod off, scaring the hell out of us if we happen to be driving at that time. Famous disasters in our time, Chernobyl, the space shuttle Challenger, and the Exxon Valdez are all disasters precipitated by sleep deprivation or sleep restriction. It is estimated that there is a annual loss to the business sector of approximately $200 billion just in absenteeism and lost productivity due to sleep deprivation.
After 20,000 years of evolution, we deny ourselves the truth that we are not machines, and denying that we need sleep. If you are lucky enough to live to the ripe old age of 90, you would have slept for 36% of your life, or about 32 years. Thirty two years of your life is a significant chunk of time, therefore sleep must certainly be an important part of our body’s overall health and well-being. But, over the last 50 years and especially since the Industrial Revolution and Mr. Thomas Edison and his lightbulb, we are sleeping at least 20% less than before, that is, we are losing one day of sleep per week.
Artificial light today impacts nearly every biological system, and it does not even take that very much to have an effect, like checking your smartphone or watching TV, or on your iPad in bed at night, giving rise to the term “iPad Insomnia”. Saying to yourself, I’m just gonna read on my iPhone or iPad until I get sleepy and then I’ll fall asleep. That extra “blue light”, or full spectrum light that tells us we should be awake is what is actually preventing you from falling asleep. Our light/dark cycle is regulated by many different hormones, one being melatonin. You may recall from reading about natural supplements, that melatonin will assist you in falling asleep, as it is a key hormone in regulating our daily dark and light cycle. But we have the ability to make our own melatonin, and that happens when all the lights are off. That means no brilliant bathroom lighting to brush your teeth just before going to bed, no bright night lights to assist you to find a bathroom in the middle of the night , no bright LED alarm clocks to wake you in the morning.
Your brain and your body needs complete darkness. Just by adding 4 hours to the usual 12 hours in our day is like “body-slamming” the autonomic nervous system and it leads to a significant increase in body fat despite not eating more or moving less.
Excess artificial light is a circadian disruptor. Diet and exercise will have a very different impact on someone with circadian rhythm misalignment. It will not work until circadian rhythms are re-aligned.
So not just looking at this chronic sleep deprivation, but acute sleep restriction. Not getting a full amount of sleep each night is equally disruptive. Researchers such as Dan Pardi, looked into subjects that did not get a full night’s sleep, and how that affected their decision making, particularly with respect to food choices. There they studied certain chronic sleep conditions on hormone regulation, like leptin and ghrelin, the hormones that affect energy regulation and food intake.
- In sleep, 3 key elements are essential for sleep to be beneficial; those three elements are timing, intensity and duration.
- The duration element is easy to define, that is what chunk of time did you sleep in a 24 hour period?
- The timing element is the circadian phase. Circadian rhythm is the 24 hour patterns that our bodies, organs and cells maintain, of which sleep is one of them. All of our organs, hormones, cells synchronize every 24 hour period with the master clock. The master clock is entrained by light entering your eyes every day.
- The intensity of your sleep has to do with the stages as you sleep, your body and your mind go through different phases or depths of sleep. During this area of sleep, the brain is replaying memories in the form of dreams, trying to consolidate and make order of your memory warehouse. At night during this phase of sleep, it’s like little gardeners come in and prune your neurons, clipping out the ones that don’t need to be filed and stored. The clippings fall on the ground, and the other gardeners and janitors sweep the unneeded debris to the front of your brain for disposal. This is a very active period for the brain. This is the time the restorative process takes place. This is the most important time for an athlete to reap the benefits of the proper nutrition and hard workout you did today. You go to bed dog tired from your long run and long day at work, and you wake up refreshed… How does that happen? During sleep, the space between brain cells increases by about 60%, creating room for our brain cells to excrete their neurotoxic substances, which are byproducts of expended energy. So, if you are not getting enough sleep those substances build up, and can potentially do harm to our overall health. Thank the little janitors that sweep that stuff out every day.
When a person sleeps, their cells undergo a cycle of repair the provides both oxygen and glucose. When one stays up all night, the brain cells are denied the products of the cycle, severely hampering the organ’s reactions to stimuli and instructions. Every cell in our body needs food… and every cell produces waste. All of those things occur in a regular, regimented way when we’ve slept well. When we interfere with that, systems go out of sync. During sleep, the bloodstream is cleared of a substance that researchers call substance S. Many believe substance is adenosine, a byproduct of energy production that cells release into the blood throughout waking hours. Without sleep, the blood gets clogged with substance S, slowing us down from head to toe. It is as though there is a toxic substance building up in you, where are the more you’re awake, the more you see this stuff floating about in the bloodstream, and the only way to get rid of it is to sleep.
Sleep deprivation and weight gain
A hypocaloric diet plus lack of quality sleep equals more lean muscle mass loss… and less fat mass loss.
Studies conducted with college students, all lean, no underlying metabolic issues, were sleep restricted for a period of four days. Several hormone levels were measured, but most remarkably the food choices were noted in the sleep deprived subjects. High calorie, processed foods, containing sugar and white flour were the most sought after by the students. The brain will seek out certain foods that are most rewarding to make up for the loss of sleep.
Translation: don’t go on a calorie restricted diet or try to lose weight until after you’ve done everything possible to improve circadian rhythms – get plenty of sleep, don’t skip breakfast in the morning… If you have not addressed this prior to our your weight-loss efforts, then more muscle is lost than fat. So even if you started paying attention to circadian rhythm’s later in the game, you’re already significantly handicapped.
Caffeine and Sleep
Yes, we all need it, love it, and I’m never going to tell you to stop drinking coffee. Just know that after a certain time of day, it’s time to switch to decaf.
- Sleep pressure is the increase in the need to sleep based on the amount of byproducts of energy consumption that have built up in the brain. As you use up energy during the course of your day, this buildup leads to the need for sleep. This sleep pressure tells you “I need to go to sleep now”. This is the body’s natural proclivity to establish balance, recall the term homeostasis.
So where does caffeine come into all of this?
- Caffeine is a potent adenosine receptor antagonist – it blocks the adenosine from binding to its receptors and increasing “sleep pressure”. (remember ATP)
- When we sleep, our brains flush out potent neurotoxins. We consolidate memories, we reinforce learning, we repair our bodies, fight off infection and disease… We replenish hormones and neurotransmitters… in essence, we put our bodies in a physiological state to thrive for the next day, to do it all over again.
- If caffeine is consumed later in the day, it will delay the housekeepers in your brain of clearing out the unnecessary clutter. It also may have a negative effect on your ability to dream. We need dreams… some theorize that those feel good dreams secrete substances that make us feel good making up for the lack of stimulation during waking hours. Many psychologists believe that we work through our daily psychological struggles through dreams.
- Sounds like the perfect drug! We should be addicted to sleep.
- It is a good idea to switch to decaffeinated coffee and tea after lunch, giving your body enough time to purge its ability to perform the necessary housekeeping at night.
So what’s my “take-away” from all of this?
We take care of ourselves nutritionally, emotionally, and physically, but sleep seems to be an afterthought or an exception to this rule. We contradict ourselves daily by saying “listen to your body”, but sleep again is that one thing that suffers so we can get a bit more done before turning in each night.
Some of the bullet points would be:
- Our bodies are entrained by light – try to reduce the use of electronics with “full-spectrum” or “blue-light” after the sun has gone down.
- Install the free program “ f.lux” on your computer – it will change the frequency of the light emitted from your computer, so at the end of the day it will be a softer light, allowing the brain to know that it is 8 pm and not 12 noon.
- Remember, most of the muscle and tissue repairs and building is done at night when you sleep – it is crucial that you try to sleep before 10 pm if your day started at 6 am or so. One deep REM sleep phase happens between 10 pm and midnight, another around 4 am. If you have a FitBit, iPhone app that tracks your sleep…use it. It is a very important tool in your training to know if you are getting the proper amount, duration and intensity of sleep. All of the great foods that you give your body, all of the training runs and HIIT will be severely compromised without proper sleep.
Your closing thought, to make it work for you in your hectic life:
“It is better to be consistently good, than intermittently perfect”
Once again, thanks for letting me ramble from my soapbox today. I hope that some of you find some tidbit of knowledge that helps you in your trail running endeavours, to be faster, stronger, or most importantly, happier. Hope to see you on the trails soon.
- Russell Foster: Why do we sleep? TED Talk
- Sleep, Circadian Rhythms and the importance of Light & Dark. Dan Pardi, Stanford University, Sigma Nutrition Radio
- Knutson et al., The metabolic consequences of sleep deprivation.
- Spiegel et al., 2004, Leptin levels are dependent on sleep duration
- Spiegel et al., 1999, The impact of sleep debt on metabolic and endocrine function
- The melanocortin-4 receptor integrates circadian light cues and metabolism, Endocrinology, 2015 May; 156(5). Arble,DM, et al.
- Dr. Kirk Parsley, America’s Biggest Problem. TEDx Talks, TEDxReno
- Effect of Sleep on Appetite Regulation, Food Choices & Glucose Metabolism, Sigma Nutrition, Limerick, Ireland. Lennon, D.
- Circadian disruption impairs survival in the wild, Calories Proper, Feb. 20, 2015
- Metabolic consequences of sleep and sleep loss. Sleep Med 2008 Sept; 9 Suppl 1:S23-8. Van Cauter E1, Spiegel K et al.
- Melatonin, L-tryptophan, 5-HTP