1. Exercise Science Program
The Negative Effects of Exercise on the Quality and Quantity of Sleep in Athletes
CJ Cofrancesco
Exercise Science Program
Literary Review
Tanaka and colleagues investigated the effects of short naps and exercise at the moderate level on elderly who have difficulty sleeping.19 There were six elderly participants in the study ( years).19 Over the course of a 4 week period participants took a 30 minute nap after lunch, between 13:00 and 15:00.19 At 17:00 moderate intensity exercise was performed for 30 minutes.19 A 1 week pre and post intervention was conducted to measure all participant’s activity levels.19 All data was collected via wristwatch actigraphy.19 As a result of the experiment participants had a significant decrease in wake time after sleep of an average of 83.2 minutes from the pre intervention to an average of 28.2 minutes in the post intervention.19 Nodding in the evening also had a significant decrease from pre to post intervention from minutes to minutes.19 Sleep efficiency in participants had an increase from the pre intervention of an average of 73.9 percent to an average in the post intervention of 89.7 percent.19 Participants also reported feeling less sleepy during the day time after the intervention.19 Tanaka and colleagues concluded that the intervention of a 30 minute nap between 1:00 pm and 3:00 pm followed by moderate exercise increased the sleep quality that elderly people obtained.19
Wong, Halaki, and Chow explored the effects of moderate to vigorous aerobic exercise on the sleep need of sedentary young adults.2 There were twelve participants, 9 females and 3 males, in the study ( years).2 All participants were sedentary young adults with body mass indexes less than 30.2 Participants were randomized into a no exercise group or to a bout of exercise on a treadmill at 45%, 55%, 65%, or 75%.2 Wristwatch actigraphy was used throughout the whole experiment to collect data as well as polysomnography on overnight stays.2 Participants who exercised at 65% and 75% of their VO2 max spent more time in total light sleep compared to the no exercise group.2 Wong, Halaki, and Chow stated that high intensity exercise caused participants to spend more time in light sleep than those who did not exercise.2
Thornton and colleagues investigated the effects of a 2 week high intensity training camp on the sleep activity of professional rugby athletes.20 There were 31 professional rugby players in the study ( years).20 All participants took part in a 7 day training period at home for pre-intervention measurements.20 Participants then traveled to Corio, Australia and dormed while participating in a 13 day high intensity training camp.20 The first week included 5 training days with a total of 11 training sessions and 5 recovery sessions.20 The second week included 3 training days with 5 training sessions and 3 recovery sessions.20 Wristwatch actigraphy and subjective sleep diaries were used to collect all sleeping data.20 During the home portion of the experiment rugby players had an average total sleep time of 7 hours and 17 minutes compared to a reduced average total sleep time of 5 hours and 51 minutes at camp.20 Sleep efficiency also had an average decrease from home compared to camp of 88.1 percent versus 79.6 percent.20 Thornton and colleagues stated that, “due to intensified training loads” high intensity training camps have a negative effect on the sleep quality, sleep efficiency, and wake after sleep time, of professional rugby athletes compared to training at home.20
Sargent and colleagues explored the effect of early morning training on the amount of sleep obtained by elite swimmers during a 2 week high intensity training camp.16 There were 7 nationally competitive swimmers1 female and 6 males, who participated in the study ( years).16 All swimmers participated in a 2 week high intensity training camp, with 12 days of training beginning at 6:00 am, and 2 days of rest.16 All sleep data was collected by wristwatch actigraphy and subjective sleep diaries.16 On nights before training days swimmers typically went to bed and got out of bed significantly earlier compared to nights before rest days.16 The average bed time and out of bed time before training days was 11:05 pm and 5:48 am.16 The average bed time and out of bed time before rest days was 12:32 am and 9:47 am.16 There was also a significant difference in the amount of time swimmers spent asleep the night before training days, receiving on average 5.4 hours of sleep, compared to the night before rest days, receiving on average 7.1 hours of sleep.16 Sargent and colleagues expressed that the average amount of sleep obtained by the swimmers each day was low, the sleep efficiency was substandard, and less sleep was received on training days compared to rest days.16
DISCUSSION
There are a variety of methods of measurement that can be used to evaluate the quality and quantity of sleep that athletes are receiving, sleep efficiency is one of the most important. Sleep efficiency is a ratio of the time spent asleep to the time spent in bed. When Tanaka and colleagues introduced an intervention of nap and moderate exercise, sleep efficiency increased by percent, from percent to percent.19 Thornton and associates had a reduction in sleep efficiency when the high intensity rugby training camp shifted from home to camp for a total decrease of percent.20 The home sleep efficiency was percent and the camp dropped down to percent.20 When Sargent and collaborators experimented on the amount of swimmers acquire on high intensity training days compared to rest days the sleep efficiency was lower on training days. According to the study elite swimmers obtained percent sleep efficiency the night before training compared to the percent they obtained the night before a rest day.16 Based on the data from the studies mentioned above it appears that athletes had a reduced sleep efficiency during high intensity exercise compared to moderate intensity exercise.
To fully evaluate the quality and quantity of sleep that athletes are obtaining the total sleep time is another crucial measurement that needs to be evaluated. In Wong and colleagues investigated the different effects of intensity of aerobic exercise on the quality and quantity of sleep compared to no exercise, higher intensity exercise had a lower total sleep time compared to moderate intense exercise and no exercise.2 When participants exercised at a high intensity of 65% they had less average total sleep time compared to the no exercise group by 6.9 minutes.2 When participants exercised at a moderate intensity of 45% total sleep time was greater by an average of 32.7 minutes compared to the no exercise group.2 According to the data high intensity exercise decreased the total sleep time participants received compared to the no exercise group and on the contrary moderate intense exercise had a higher total sleep time than the no exercise group. The total sleep time in Thornton and associates high intensity rugby training camp decreased when athletes trained at camp compared to at home. The total sleep time at home was 7 hours and 17 minutes + 1 hour and 7 minutes and decreased to 5 hours and 51 minutes + 1 hour and 3 minutes for a total reduction in total sleep time by 1 hour and 26 minutes + 4 minutes.20 During both high intensity portions of the training camp, at home and camp, professional rugby players were not, on average, obtaining the minimum required amount of 8 hours of sleep per night. National swimmers during Sargent and collaborators early morning high intensity training camp received less sleep the night before training days compared to the night before rest days. The night before rest days national swimmers received an average of 7.1 hours of sleep which was higher than the amount of sleep they received the night before training days which was an average of 5.6 hours of sleep per night.16 National swimmers received and average of 1.5 less hours of sleep the night before training days compared to rest days, and overall were not obtaining the minimum 8 hours of sleep per night throughout the whole camp.16
ABSTRACT
The purpose of this study was to review scientific literature to determine if exercise has a negative effect on the quality and quantity of sleep in athletes. Four scientific articles were used to review the effects of exercise on the quality and quantity of sleep. When high intensity exercise was introduced total sleep time and sleep efficiency decreased.
Hypothesis
It is hypothesized that higher intensity exercise has a negative effect on the quality and quantity of sleep that athletes obtain.
Introduction
Sleep is a well-known method of recovery that helps the body and mind recuperate from the effects of exercise. Researchers have investigated the effects of post exercise napping and its increase to athletic performance with a 30 minute or 90 minute nap being optimal for recovery before another bout of exercise.13–15 Research has been conducted investigating the effects of elite athlete’s schedules on the quality and quantity of sleep obtain. Eight hours of sleep per night is recommended, but elite athletes on average are sleeping about 6.5 hours per night.8,9,16 The schedules of elite athlete’s include many variables such as traveling, competition, and training. The average time elite athletes report falling asleep is around 11:30 pm and their training schedules can start as early as 6 in the morning leading to a reduction in the amount of sleep they receive.8,9,16 Research has also explored the quality of sleep measurement devices with polysomnography being the gold standard for measurement. Polysomnography is a very expensive device and difficult to transport, while wristwatch actigraphy and activity monitors were found to be easier, cheaper, and more reliable forms of sleep quality and quantity measurement devices.3,17
Muscle recovery by means of sleep is an important activity for the body to accomplish due to the physical and mental demands from exercise. There are many elements that incorporated into the structure of a workout regimen. The American College of Sports Medicine has an established principle called F.I.T.T. –V.P (Frequency, Intensity, Time, Type, Volume, and Progression) which includes all the variables used to design a workout.18 It is hypothesized that higher intensity exercise has a negative effect on the quality and quantity of sleep that athletes obtain. The results of several investigations on the effect of the intensity level of exercise on sleep quality and quantity in athletes will be outlined during this review.
TAKE HOME MESSAGES
Based on the findings in this literary review it appears that high intensity exercise does have a negative effect on the quality and quantity of sleep that athletes obtain. Both sleep efficiency and total sleep time decreased when participants performed high intensity exercise.
This work was presented at the 2015 Sacred Heart University Academic Festival