Sleep or Die!
Sleep experts claim that to function optimally, we need to spend at least one third of our lives sleeping, which equates to about 24 years of total sleep. Sleep provides us with a whole host of benefits, which include neurological, physiological, and biochemical housekeeping. These processes keep us alive, and our mind running sharp. About 150 years ago, the average person slept 10 hours. In the last century, it has been reduced by 20% to 8 hours per night. More recent studies have shown the average is now down to 7 hours a night. This is not a good trend for our health, in both the mental and physical realm. Work and commute times have been increasing, which exacerbates this sleep problem. Sleep is one of the essential elements to good health, and it is something I have struggled with, ever since the start of college. My friends and I would put in long hours of studying and work, then we’d stay up late partying, watching movies, playing video games, even though we knew we had to get up at the crack of dawn the next day. We saw it as a badge of toughness, that we could keep pushing ourselves through the fatigue. We were racking up huge sleep debts that we would try to make up for with naps and sleeping in on the weekends, which is not a sound strategy. Let’s dig a little deeper into this whole topic of sleep. We’ll look at sleep cycles and our biological clock, what science shows about the health consequences, and what we can do to improve our sleep.
In the book, Power Sleep by Dr. James B. Maas of Cornell University, the author identifies 4 stages in a sleep cycle. Stage 1 is characterized by light sleep and theta waves in the brain, as measured by an EEG. We are still able to respond rather quickly to stimulus in our environment, some would call it being “half asleep.” Stage 2 is often considered the first stage of real sleep. It is a mix of theta waves plus K-complex waves and sleep spindles. Muscle tension and brain stem activation is greatly reduced. This stage usually lasts 10 to 20 minutes and the person becomes completely disengaged from the environment. Stage 3 sleep is typically reached after about 30 minutes into the cycle. The stage is a combination of theta and delta (very low frequency and high voltage) waves. As the theta waves disappear all together, the person enters stage 4 sleep. The subject is completely disengaged from the environment and in a deep sleep. If awakened at this point, we will be mentally groggy. Delta wave sleep is where everything slows down, which includes our heart rate and breathing, plus we have complete muscle relaxation. This is when humans are at our most vulnerable, and yet, it is when we accrue the greatest health benefits. It is at this point that we are the closest to what would be defined as hibernation.
The health benefits of slow wave sleep include:
- Helps with recovery and growth by increasing blood supply to the muscles, reducing metabolic activity in favor of tissue growth and repair, and allowing the greatest secretion of growth hormone. A study showed that runners had more stage 4 (slow wave) sleep after completing an ultramarathon. Obviously, they needed a lot of repair.
- Improves the function of the immune system. Research has shown that sleep deprivation can lead to negative changes in how the immune system is functioning.
There is one more stage in the sleep cycle that cannot go unmentioned, the REM (rapid eye movement) stage. After 30 to 40 minutes of delta (slow wave) sleep, the brain retraces through the stages, heading back to 3, then 2, but instead of going back to stage 1, you enter REM sleep. It’s basically a bridge between sleep cycles where dreams occur. The sympathetic nervous system becomes very active, even more so than when we are awake or in deep sleep. Our blood pressure, pulse, breathing, and temperature, all increase. Theta waves are joined with alpha waves.
The benefits of REM sleep include:
- Allows memories to be stored and retained by the growth of neural connections.
- It is the time when memories are organized. Important memories are moved into long term storage.
- Neurotransmitters are replenished for continued learning and retention.
A sleep cycle generally takes 90 to 110 minutes, and the average person experiences 4 to 5 of these cycles during their nightly sleep. Before we move on, it’s worth mentioning a few things about our biological clock. Here is how Dr. Maas describes our biological clock in his book, “The biological clock is actually two tiny neural structures, called the suprachiasmatic nuclei, located in the center of the brain. The clock controls rhythms of alertness (but not sleep), body temperature, and hormone production. These rhythms are an intricate and orderly series of psychological and physiological changes that occur approximately every 24 hours and are called circadian rhythms.” In studies on subjects that have no time cues, the biological clock functions on more of a 25 hour cycle. According to our clocks, our alertness peaks and dips during the day. We are usually very alert in the morning, then it dips in the early afternoon to only increase again in the late afternoon. Our alertness dips again in the late evening, and doesn’t come back up until morning. For optimal living, we should be in tune with our own biological clocks and circadian rhythms.
There have been many studies involving sleep and they show the numerous health consequences associated with it. First off, as I mentioned earlier, sleep deprivation can alter the immune system for the worse. A recent study showed that there can be an increased risk of cardiovascular disease mortality with short sleep and disturbed sleep. Research out of the Journal of Internal Medicine exposed that sleep disturbances were associated with total and cause specific mortality in both sexes. In healthy men, an elevated resting heart rate had to also be present for these findings to be true. The study also revealed that disturbed sleep correlated with abnormalities in lipid and glucose metabolism, blood pressure, and lung function. Another study revealed that sleeping less than 7 hours in a 24 hour period over a prolonged period of time, had an increased risk of mortality in both men and women. Research has also brought to light that women are more at risk for elevated levels of C-reactive protein (sign of inflammation) when they have poor sleep quality. Looks like we need to get more sleep. Hold on, can there be too much of a good thing? There has been some research linking long sleep duration with increased mortality risk and you can find that study here. There are two things to take in account, one is that maybe these people slept extra long because they were already suffering from a health problem, and two, these people had low activity levels which definitely had to be accounted for in their mortality risk.
So what can we do to improve our sleep? Here are some tips:
- Get the amount of sleep you require each night. Not every person is going to need the same amount of sleep, so it’s pointless to give a number here. You’re are going to have to do a little sleep detective work if you want to find your own optimal number. You should be able to wake up without an alarm clock if you are getting the right amount of sleep. looking at the research, Dr. Maas states in his book, “At minimum most people absolutely need to obtain at least sixty to ninety minutes more sleep than they presently get.”
- Have a regular sleep schedule that you consistently follow, even on the weekends. This will help keep your biological clock in balance.
- It’s best to sleep in one continuous block. This will ensure that you get restorative sleep that will allow your body to repair and your mind to function optimally.
- Try and make up for lost sleep as soon as possible and try not to make it a habit. It’s unlikely that we can travel through life without experiencing any sleep deprivation. Things in life will come up that will get us out of our normal sleep schedule, but we should try to correct that quickly. Napping can be a great way to make up for lost sleep. However, it’s best to get continuous sleep and not rely on napping to make up your sleep debt. Here is a good article about napping and it has a nice info-graphic about the how long to nap.
- Reduce your exposure to bright light and electronics at night. Light can be a stressor, contributing to poor sleep hygiene, according to this research study.
I hope that you understand the importance of sleep. We may convince ourselves that we don’t need much sleep, but in most cases we our just acquiring a sleep debt that we never pay back. We are suffering from reduced physical and mental performance, and health problems on top of that. According to this article at Fatigue Science, due to the concept known as renorming, we actually believe we are performing our best, when we are not. Renorming means that we compare how we feel today, to yesterday, and maybe the day before that, but don’t really remember beyond that. A gradual decline goes unnoticed by us. You can read more about it here. It’s easy to get caught up in a viscous cycle where we continually sacrifice sleep, but it’s worth the effort to make it priority. After all, if we didn’t sleep, we would die!