The Science of Sleep: 1v1 With Dr. Czeisler
by Danny Moon
It would be an understatement to say that today’s athletes are tasked with an incredible amount of work. In order to compete at a high level, athletes must invest inordinate amounts of time into training, studying, eating, and practicing. With so many responsibilities to juggle, athletes are often forced to push time-consuming activities to the side. Unfortunately, one of the biggest victims of an athlete’s hectic schedule is arguably the most important aspect of it all: sleep.
To delve deeper into this phenomenon, CoachUp sat down with Doctor Charles A. Czeisler, who currently serves as the Director of Sleep Medicine at Harvard Medical School and the Chief of Sleep and Circadian Disorders at Brigham and Women’s Hospital. Over the past 30 years, Dr. Czeisler has had many notable experiences. In 2012, Dr. Czeisler worked as a consultant to Mitt Romney during the presidential election; and, just one year later, he served as an expert in the lawsuit involving the death of pop star Michael Jackson. Recently, though, Dr. Czeisler has invested much of his time researching the correlation between sleep and athletic performance.
Through his research and experiences with teams such as the Portland Trail Blazers, Boston Celtics, and Boston Bruins, Dr. Czeisler has accumulated a wealth of knowledge about the power of sleep and more specifically, the importance of sleep to athletes. We thought speaking to Dr. Czeisler could be an important asset for all our growing athletes -- so listen up!
CoachUp: To get straight into things, why is sleep important for athletes?
Dr. Charles Czeisler: Getting enough sleep isn’t necessarily going to make you a great athlete. Simply put, if you never practice and have no talent, it isn’t going to happen. However, if you're an outstanding athlete and you don’t get enough sleep, you're not going to be able to play at your full potential. There are several reasons why: First of all, sleep deficiency degrades reaction time. For example, if you were to stay up all night, your average response time would be three times longer. Instead of having a response time that’s a quarter of a second, it’ll be three quarters of a second and so on.
Additionally, your slowest reaction time would go from half a second to five or six seconds. That is one of the most obvious and fundamental reasons sleep is important for athletes, but there are other reasons too. In terms of injuries, sleep plays an incredibly important role as well. Sluggish reaction times make you more susceptible to injuries because one of the ways you avoid injuries is through quick reactions. For example, getting out of the way of a fastball, ducking when your opponent swings at you, evading a slide tackle, etc. When you don’t have sufficient sleep, the body’s inflammatory response becomes greater. That means that you’ll have more inflammation, more soreness, and longer recovery times. Putting these two together, a lack of sleep will not only lead to a greater risk for injury, but it will also lead to a longer recovery time after you get injured.
A deficiency in sleep also weakens your immune system by an incredible amount; if you get exposed to the virus that causes the cold, you are 300% more likely to become sick. This is obviously a negative for athletes because if you are sick, you cannot even compete! While everything we've discussed about sleep is pertinent, the most important reason why sleep is important to athletes is because during sleep, the brain rehearses tasks that have occurred during the day. If you don’t sleep or don’t sleep well after training, you will never learn the skills that you practiced earlier that day. This is because you lose REM sleep when you sleep poorly.
REM sleep is key to all of this because it is the stage of sleep where you integrate new memories at real-time speed with everything else you know. This period of sleep is why sometimes during the playoffs, you’ll hear a team say, “We figured out the moves of the other team and that’s why we beat them in Game 3…” That “figuring out,” often happens during sleep because you are unconsciously running through the activities of the previous day.
All in all, sleeping well does not necessarily make you a great athlete, but if you want to maximize every ounce of potential you have, sleep is crucial.
CU: So how much sleep would you recommend to the average athlete?
CC: Well, this is going to sound impractical, but around eight to ten hours a night. A study done at Stanford University had young athletes sleep for around ten hours a night for a full month. In this month, the performance of these athletes improved dramatically. For runners, sprint times declined. For basketball players, shooting percentages increased, For swimmers, turning times decreased.
Overall, the energy of all of the athletes was self reported as much higher as well. So, in an ideal world, eight to ten hours would be my recommendation.
CU: What are the recent trends in sleep within professional teams since you have started consulting with them?
CC: Some of the teams I’ve worked with are using devices to record their players’ activity, sleep, and steps. There are now analytics companies that are also doing exactly that type of monitoring. Basically what happens is that an athlete’s sleep is monitored, feedback is given, and then the teams or colleges will plan their workout schedule based on this information. This is just one of the few changes that I’ve noticed in terms of recent trends.
CU: To give some parting messages, what advice would you give to athletes and parents reading this blog?
CC: I would tell them that there are three key aspects of sleep. First, which we covered, is the duration of sleep that athletes get. Just as important as the duration is the consistency in the timing of sleep. This is, of course, is the most difficult aspect for many people because so many variables affect what time we may go to bed. The internal clock works best when there is a consistency to bedtime and wake time.
This is as important as the duration of sleep because the brain actually adjusts to conserve critical sleep stages if the amount is consistently insufficient. But, there is no way for the brain to anticipate if you’ve been going to bed at 10 PM and wake up at 7 AM and then suddenly the next day you get up at 5 AM. This discrepancy leads to a loss in critical sleep stages that often occur in the latter half of the night. The last important aspect of sleep is the quality of your sleep. If you sleep in an environment in which you cannot maintain consolidated sleep -- noise, brightness, etc -- then that will degrade the quality of your sleep.
So, you really need to pay attention and hit those three factors if you want to maximize your potential as an athlete.