This is the 1st in a 2-part series on sleep and how it impacts performance. References for both portions will be included at the bottom of both posts.
Sleep could very well be the most powerful recovery tool available to athletes. As powerful of a “performance enhancer” as sleep can be, poor sleep can have equally profound negative consequences. In a review on recovery strategies centered around the central nervous system (e.g. your brain), Rattray, Argus, Martin, Northey, and Driller (2015) point out that sub-optimal sleep is associated with compromised motivation and immune function, symptoms of over-reaching (i.e. the precursor to over training), and reductions in brain glycogen (i.e. fuel for brain activity). Sleep deprivation is also associated with increased levels of the catabolic hormone cortisol, along with markers of systemic inflammation (Wright et al, 2015). Halson (2014) adds that reducing sleep to <6 hours per night for 4 nights leads to the aforementioned changes, but also changes in blood sugar regulation and appetite, and that a night of sleep deprivation can lead to decreases in power, strength, repeat sprint ability, endurance and perceived effort.
In fact, according to Czeisler (2011), sleep deprivation leads to performance decrements comparable to having a blood alcohol level of 0.10%.
Simply, with sub-optimal sleep all aspects of performance relevant to team sport athletes are compromised. As a consequence, there’s a constant internal battle between tapping into mental reserves to maintain a high level of performance and a progressively decreased motivation to do so.
Much of this research focuses on sleep deprivation (e.g. not sleeping at all for 24-48 hours), which may have some application to college athletes pulling all-nighters to prepare for exams. Given how rare these circumstances are, though, it’s important to note that consistent mild sleep deprivation (e.g. less than 6 hours/night for several nights per week) can have similar influences as total sleep deprivation. These physical and mental performance decrements can appear after only two nights of partial sleep deprivation (Halson, 2014).
Furthermore, going to bed 2-2.5 hours later than normal can negatively affect sport-specific skills, such as serving accuracy in tennis (Reyner & Horne, 2013), and presumably shooting accuracy in sports like soccer, hockey, and basketball. Importantly, partial sleep deprivation leads to more pronounced performance impairments in the evening of the following day, which is when most competitions are scheduled (Thun, Bjorvatn, Flo, Harris, & Pallesen, 2015).
Sleep is divided into two major categories: Rapid Eye Movement (REM) and Non-Rapid Eye Movement sleep, the latter of which is subdivided further into stages associated with increasing “depths” of sleep. REM and Deep Sleep have specific physiological advantages that warrant noting:
While this is an oversimplification, you can think of REM sleep as mental recovery and deep sleep as physical recovery.
As is the approach I take with designing training programs, any specific sleep recommendations should be made with some sort of assessment/tracking information. There are dozens of options, but the overwhelming majority are all finding different ways to assess “actigraphy,” which uses body movement to make inferences about whether you’re awake or sleeping, and if sleeping, what stage of sleep you’re in.
While it’s not cheap, the device I like the best for this purpose is the Res Med S+. Not only does it provide a daily “Sleep Score” based on your total sleep, wake, REM, Light, and Deep sleep times, but it also ties in quick tips/education based on your specific scores to help you better address your limitation.
It also has a few basic questions about caffeine and alcohol consumption, and perceived stress levels throughout the day so you can start to understand the relationships that these things have with your personal sleep patterns. The education piece is better than anything else I’ve come across and will help keep you engaged on improving your sleep duration/quality, which is essential to long-term success.
My only qualm with actigraphy measures is they’re easily influenced by other people/animals in the bed. If you have a significant other or overly human-like pet (see below) sleeping with you, they’ll likely influence your scores to a varying degree depending on their movement.
My sleep quality is directly linked to whether Ruxin sleeps upside on my head, or on Emily’s.
As an alternative to actigraphy-based measures, there’s an app called “Sleep Rate” that ties in with Bluetooth HR monitors like the Polar H7 and provides very similar information to the S+. This is what I use when I travel. The heart rate strap is a little invasive, but I like this data because it’s a direct reflection of my physiology, not an inference from the cumulative movement patterns of the bed. The app itself is free, and with a ~$50 cost for the Polar H7 that can be used with other free apps on your phone for training purposes, it’s a worthwhile investment.
Part 2 of this series will have tips on how to optimize your sleep quality, including how to “trick” your brain into thinking it’s tired and effective supplements you’ve never heard of.
To your success,
Kevin Neeld
HockeyTransformation.com
OptimizingMovement.com
UltimateHockeyTraining.com
References:
Abbasi, B., Kimiagar, M., Sadeaghniiat, K., Shirazi, M., Hedayati, M, & Rashidkhani, B. (2012). The effect of magnesium supplementation on primary insomnia in elderly: A double-blind placebo-controlled clinical trial. Journal of Research in Medical Sciences, 17(12), 1161-1169.
Abeln, V., Kleinert, J., Struder, H., & Schneider, S. (2014). Brainwave entrainment for better sleep and post-sleep state of young elite soccer players – A pilot study. European Journal of Sport Science, 14(5), 393-402.
Czeisler, C. (2011). Impact of Sleepiness and Sleep Deficiency on Public Health – Utility of Biomarkers. Journal of Clinical Sleep Medicine, 7(5), S6-S8.
Gradisar, M., Wolfson, A., Harvey, A., Hale, L, Rosenberg, R. Czeisler, C. (2013). The Sleep and Technology Use of Americans: Findings from the National Sleep Foundation’s 2011 Sleep in America Poll. Journal of Clinical Sleep Medicine, 9(12), 1291-1299.
Halson, S. (2014). Sleep in Elite Athletes and Nutritional Interventions to Enhance Sleep. Sports Medicine, 44, S13-S23.
Mah, C., Mah, K., Kezirian, E., & Dement, W. (2011). The effects of sleep extension on the athletic performance of collegiate basketball players. Sleep, 34(7), 943-950.
Mah, C. (2008). Extended sleep and the effects on mood and athletic performance in collegiate swimmers. Annual Meeting of the Associated Professional Sleep Societies, June 9; Baltimore, MD.
Rattray, B., Argus, C, Martin, K., Northey, J., & Driller, M. (2015). Is it time to turn our attention toward central mechanisms for post-exertional recovery strategies and performance? Frontiers in Physiology, 6(79), 1-14.
Reyner, L, & Horne, J. (2013). Sleep restriction and serving accuracy in performance tennis players, and effects of caffeine. Physiology & Behavior, 120, 93-96.
Thun, E., Bjorvatn, B., Flo, E., Harris, A., & Pallesen, S. (2015). Sleep, circadian rhythms, and athletic performance. Sleep Medicine Reviews, 23, 1-9.
Waterhouse, J., Fukuda, Y., & Morita, T. (2012). Daily rhythms of the sleep-wake cycle. Journal of Physiological Anthropology, 31, 5-18.
Wright, Jr., K., Drake, A., Frey, D., Fleshner, M., Desouza, C., Gronfier, C., Czeisler, C. (2015). Influence of sleep deprivation and circadian misalignment on cortisol inflammatory markers, and cytokine balance. Brain, Behavior, and Immunity, 47, 24-34.
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“Kevin Neeld is one of the top 5-6 strength and conditioning coaches in the ice hockey world.”
– Mike Boyle, Head S&C Coach, US Women’s Olympic Team
“…if you want to be the best, Kevin is the one you have to train with”
– Brijesh Patel, Head S&C Coach, Quinnipiac University