I finished my last blog and was trying to figure out what my next topic should be. This past December my mother was nice enough to gift me a Fitbit for Christmas. This is one of the many wristband activity trackers out in the market right now. After tinkering around with it, I found an interesting feature where it monitors sleep and its different phases.

Everyone knows the recommendation to get more sleep. However, most people I know sacrifice this for other priorities. We find all kinds of excuses: That new TV show, exercise, kids, hobbies etc. This year I made it a priority to get a minimum of 7 hours of sleep a day. However, when I looked at the tracker, often I go to sleep for 8 hours, and it records only 7 hours of sleep. This made me question the accuracy of this tracker and led me to think of items I wanted to address in my next post including:

How accurate are fitness trackers at monitoring sleep?

How much sleep do we need to perform at our best?

Can we make up sleep later?

Are there ways to improve on the sleep we get?

Does Nutrition Play a role in a good night’s sleep?

In the following paragraphs I will shed light on these points by reviewing the latest research on the topic.

Are Fitness trackers accurate at monitoring sleep?

Fitness trackers estimate your sleep cycles using a combination of movement and heart rate patterns. Different phases of sleep are determined by your heart rate variability. Studies have shown that activity trackers such as Fitbit and Jawbone can be acceptable sleep trackers for normal populations.1,2 Literature comparing these devices to other more accurate (and more expensive) devices found that they tend to underestimate sleep disruptions and overestimate total sleep times and sleep efficiency in normal subjects.3

How much sleep do we need?

Studies have found that if left to sleep without an alarm, the sleep tendency of adults is ~8.5 hours.4 However, the average amount of daily sleep was only 7.2-7.4 hours.4 This results in a 1.1 – 1.3 hour deficit each night. Studies on the general public have shown that sleep periods reduced by as little as 1.3 for 1 night result in reduction of daytime alertness by as much as 32%.4 These results highlight how much skimping on sleep can effect performance.

In another study measuring cognitive performance, subjects were split into groups who received 4, 6, or 8 hours of sleep each night. In the groups that received 4 or 6 hours of sleep their performance declined and the decline was cumulative and dose dependent.5 This means that performance was worse the less sleep participants received and that each day of sleep deprivation caused a successive decline in performance.



When it comes to athletes, even more sleep is likely needed. Poor Sleep quality in competitive athletes is very common.6 One study found that athletes who slept <8 hours per night were 1.7 times more likely to have had an injury compared with athletes who slept > or = 8 hours.7 Those that are injury prone should really evaluate whether they are getting adequate sleep.

Individual differences make it hard to determine the exact amount of sleep needed for everyone. The best way to determine your own requirement is to go to bed when tired and sleepy, and to get up in the morning feeling refreshed without an alarm for a few days to find the ideal time for you.8

I almost never wake up without an alarm; what about you? I might have to try out this experiment myself!

Can you make up lost sleep?

Sleep extension studies on athletes and non-athletes have found that extending sleep time can be beneficial.9,10 One study followed NCAA basketball players to see if extended sleep would benefit performance. The baseline amount of sleep players had on average was 6.68 hours. After 3 weeks of extending sleep time to 10 hours per day, the players were found to have significant improvement in shooting percentage, sprint times, reaction time, mood, fatigue, and vigor.



Napping is another strategy that can be used to make up sleep. Research indicates that a 30 minute nap after partial sleep loss improved sprint time and alertness.11 It can also be beneficial for athletes who must wake up early for training or competition resulting in sleep deprivation.12 Therefore, if you know you have a competition coming up and you won’t get the sleep you need, a pre-planned nap may boost performance. Keep in mind that naps longer than 30 minutes may increase the likelihood for grogginess.

Are there ways we can improve the sleep that I get?

Two easily controllable factors that have been shown to help improve sleep is blocking light and avoiding temperature extremes. Exposure to light inhibits the release of melatonin, which helps the body prepare for sleep.13 Therefore strategies should be sought to minimize light during sleep. Although it may look funny, using a sleepy eye mask is a cheap effective way to improve your sleep; especially while traveling because you don’t know how good the curtains will keep light out. I have used this one found on amazon: Sleepy Eye Mask, however blackout curtains work too.



Extreme temperatures have also been shown to disrupt sleep. Avoiding hot or cold showers just before bed and the prevention of extreme ambient temperatures can help improve sleep quality.13

Can nutrition Play a role in a good night’s sleep?

Nutrition can play a large role in the quality of ones sleep. Research has found that meals consumed within 1-2 hour of going to sleep tend to interfere with the quality of sleep.14 The macronutrients of your last meal play a role on sleep quality as well. When the final meal of the day is High Glycemic Index carbohydrates and was consumed > 1 hour before bedtime, it resulted in a shorter time period to fall asleep.14



One item particularly helpful for athletes the day before the event is melatonin. It has been found to decrease the onset of sleep in many studies.14 I don’t know about you, but many times the excitement or anxiety the day before a race or competition tends to delay the onset of sleep. Trialing melatonin supplements, or foods high in melatonin may be just what you need. In addition, consuming small doses of tryptophan can both shorten the time period to fall asleep and and improve sleep quality. High amounts of thryptophan are found in turkey, dairy products, nuts, and seeds. Melatonin can be found in nuts, seeds, or tart cherries.

If you prefer to take a supplement, a USP certified supplement can be purchased from Amazon here.

Caffeine and Alcohol:



Caffeine is known to negatively alter sleep patterns for many hours after intake, causing prolonged sleep latency, reduced total sleep time, sleep inefficiency, worsened perceived sleep quality, and REM sleep behavior disorder.14 Limiting its use to mornings may be helpful from preventing these issues. In addition, alcohol, which is a depressant that can cause drowsiness, may disrupt sleep later due to its ability to influence levels of serotonin and norepinephrine. This causes many to wake up after its sedative effects wears off and can cause you to be unable to sleep again.

In Closing:

Sleep is one of the most important things you can modify to increase performance. It is an easy thing to do, but seems to be one that is often neglected. Use this review to help improve your sleep quality and quantity.

References:

Montgomery-Downs HE, Insana SP, Bond JA. Movement toward a novel activity monitoring device. Sleep and Breathing . 2011;16(3):913-917. doi:10.1007/s11325-011-0585-y. Zambotti MD, Claudatos S, Inkelis S, Colrain IM, Baker FC. Evaluation of a consumer fitness-tracking device to assess sleep in adults. Chronobiology International . 2015;32(7):1024-1028. doi:10.3109/07420528.2015.1054395. Kolla BP, Mansukhani S, Mansukhani MP. Consumer sleep tracking devices: a review of mechanisms, validity and utility. Expert Review of Medical Devices . 2016;13(5):497-506. doi:10.1586/17434440.2016.1171708. Bonnet MH, Arand DL. We are Chronically Sleep Deprived. Sleep . 1995;18(10):908-911. doi:10.1093/sleep/18.10.908. Dongen HPV, Maislin G, Mullington JM, Dinges DF. The Cumulative Cost of Additional Wakefulness: Dose-Response Effects on Neurobehavioral Functions and Sleep Physiology From Chronic Sleep Restriction and Total Sleep Deprivation. Sleep . 2003;26(2):117-126. doi:10.1093/sleep/26.2.117. Venter R. Role of sleep in performance and recovery of athletes: A review article. South African Journal for Research in Sport, Physical Education and Recreation . 2012;34(1):167-184. Milewski, Matthew D., et al. “Chronic Lack of Sleep is Associated With Increased Sports Injuries in Adolescent Athletes.” Journal of Pediatric Orthopaedics , vol. 34, no. 2, 2014, pp. 129–133., doi:10.1097/bpo.0000000000000151. Bompa TO, Buzzichelli C. Periodization: theory and methodology of training . Champaign, IL: Human Kinetics; 2018. Harrison Y, Home J. Should We be Taking More Sleep? Sleep . 1995;18(10):901-907. doi:10.1093/sleep/18.10.901a. Mah CD, Mah KE, Kezirian EJ, Dement WC. The Effects of Sleep Extension on the Athletic Performance of Collegiate Basketball Players. Sleep . 2011;34(7):943-950. doi:10.5665/sleep.1132. Halson SL. Sleep in Elite Athletes and Nutritional Interventions to Enhance Sleep. Sports Medicine . 2014;44(S1):13-23. doi:10.1007/s40279-014-0147-0. Reilly T, Edwards B. Altered sleep–wake cycles and physical performance in athletes. Physiology & Behavior . 2007;90(2-3):274-284. doi:10.1016/j.physbeh.2006.09.017. Halson, Shona L. “Sleep in Elite Athletes and Nutritional Interventions to Enhance Sleep.” Sports Medicine , vol. 44, no. S1, 2014, pp. 13–23., doi:10.1007/s40279-014-0147-0. Afaghi, Ahmad, et al. “High-Glycemic-Index carbohydrate meals shorten sleep onset.” The American Journal of Clinical Nutrition, vol. 85, no. 2, Jan. 2007, pp. 426–430., doi:10.1093/ajcn/85.2.426.