Research Review By Christopher Howard

Date Posted:

November 2010

Study Title:

One night of sleep deprivation decreases treadmill endurance performance

Authors:

Oliver SJ, Costa RJS, Laing SJ et al.

Author's Affiliations:

School of Sport, Health and Exercise Sciences, Bangor University, Bangor UK; Olympic Medical Institute, Northwick Park Hospital, Harrow, UK; School for Health, University of Bath, Bath, UK

Publication Information:

European Journal of Applied Physiology 2009; 107: 155-161.

Background Information:

The effect of sleep deprivation on performance is an important area to investigate due to the fact that several occupational and athletic populations may be exposed to it on a short-term (or longer-term) basis. For example, military personnel, workers on rotational patterns, and athletes that travel across time zones are subject to sleep deprivation. Despite its importance, few studies have investigated the effect of sleep deprivation on exercise performance and the ones that have examined it to date report contradictory results.

Pickett and Morris (1) reported that time to exhaustion (TTE) was unaltered following 30 h of sleep deprivation, whereas Martin (2) reported only a marginally (P = 0.05) significant decrease in TTE following 36 h of sleep deprivation. In addition, the effect of sleep deprivation on pacing is unknown as previous investigations used time to exhaustion rather than fixed end point tests to determine performance.

The nature of these tests require that athletes exercise until exhausted, which is unlike most athletic events. For this reason, the authors of this investigation used a distance-based timed test to examine the effect of sleep deprivation on endurance performance.

This study examined the effect of one night of sleep deprivation on pre-loaded, 30 minute, self-paced endurance performance. In addition, the authors investigated how sleep deprivation effects pacing, cardiorespiratory, thermoregulatory, and perceived exertion. It was hypothesized that endurance performance would decrease following 30 hours of sleep deprivation.

Pertinent Results:

Participants:
  • No differences were reported in the amount of sleep participants obtained prior to starting each experimental trial (P = 0.718).
  • Participants slept for average of 496 (+/- 18) min. in the control trial whereas participants remained awake throughout the sleep deprivation trial.
  • Urine specific gravity was not significantly different between control and sleep deprivation trials at 0 h (P = 0.137) or 30 h (P = 0.112).
  • Resting core temperature was also not different at 30 h between trials (P = 0.115).
Endurance Performance:
  • Less distance was covered on the distance test after sleep deprivation - 6037 +/- 759 m, compared with the control trial - 6224 +/- 818 m, (P = 0.016). This indicated a mean percentage change of 2.9% fewer meters in the sleep deprivation group.
  • Nine of the eleven participants completed less distance in the sleep deprivation trial, whereas two participants completed greater distances when sleep deprived.
Pre-load Physiological and Perceptual Responses:
  • There were differences between trials at any points in time during the pre-load for HR (P = 0.805), minute ventilation (P = 0.753), VCO2 (P = 0.274), RER (P = 0.506), Core Temperature (P = 0.444), Skin Temperature (P = 0.207) and RPE (P = 0.271).
  • VO2 (P = 0.025)was significantly greater at 30 min compared with 5 min in the sleep deprivation trial only during the pre-load.
  • HR (P = 0.000), minute ventilation (P = 0.000), VCO2 (P = 0.004), RER (P = 0.000), Core Temperature (P = 0.000), Skin Temperature (P = 0.000) and RPE (P = 0.000) increased during the 30 min pre-load.
  • Core Temperature was significantly lower in the sleep deprivation trial compared with the control trial during the pre-load (P = 0.015).
  • There were no differences in the experimental trials for HR (P = 0.647), minute ventilation (P = 0.217), VO2 (P = 0.647), VCO2 (P = 0.557), RER (P = 0.824), Skin Temperature (P = 0.109) and RPE (P = 0.854).
Distance Test Physiological and Perceptual Responses:
  • There were no trial by time interactions during the distance test for HR (P = 0.214), Core Temperature (P = 0.404), Skin Temperature (P = 0.448), RPE (P = 0.250) and speed (P = 0.39).
  • HR (P = 0.000), Core Temperature (P = 0.000), Skin Temperature (P = 0.001), RPE (P = 0.000) and speed (P = 0.000) increased during the distance test.
  • HR (P = 0.030) and Core Temperature (P = 0.030) were lower in the sleep deprivation trial throughout the distance test.
  • There were no main effects of condition during the distance test for Skin Temperature (P = 0.938), RPE (P = 0.854) and speed (P = 0.221).

Clinical Application & Conclusions:

In this investigation, 30 hours of sleep deprivation was shown to have a negative impact on pre-loaded endurance performance. Even though the subjects completed a shorter distance after sleep deprivation, their perception of effort (RPE) was the same in both trials. This indicates that the subjects felt like they were working just as hard in the sleep deprivation trial as they had under control conditions. Therefore, it is possible that sleep deprivation affects performance through alterations in perceived exertion.

In addition to endurance performance, the authors examined cardiorespiratory, and thermoregulatory responses to exercise. The results indicated that sleep deprivation has a limited effect on cardiorespiratory and thermoregulatory responses to exercise.

Study Methods:

Participants:
  • The study consisted of 11 male volunteers
  • Mean Age: 20 +/- 3 years
  • Mean Body Mass: 77.6 +/- 7.8 kg
  • Mean % Body Fat: 13 +/- 5%
  • Mean VO2 max: 55.5 +/- 5.6 ml/kg/min
Preliminary Measurements:
  • Seven to ten days prior to beginning the experimental trials, VO2 max was measured by a continuous incremental exercise test on a motorized treadmill. Following VO2 max testing, subjects were given a 15-minute rest period. Then the treadmill speed, which elicited 60% VO2 max at a 1% gradient, was determined. This speed was used for the subsequent sub-maximal pre-load.
  • Body composition was estimated by dual energy x-ray absorptiometry and the calculated fat free mass was used to estimate resting metabolic rate. This number was then multiplied by 1.7 to determine energy intake for each participant.
  • Prior to leaving the laboratory, participants performed a complete familiarization of the experimental exercise protocol (i.e. 30 minute preload at 60% VO2 max followed by a 30 minute maximal distance test).
Experimental Procedures:
  • This experiment was a randomized cross-over design with the two experimental trials occurring seven days apart. In the control trial, subjects were allowed normal sleep. In the sleep deprivation trial, subjects went without sleep for one night.
  • To control nutritional and hydration status, subjects were provided with their estimated energy requirements and water equivalent to 35 ml/kg of body mass. Subjects were instructed to only consume this food and no caffeine was allowed.
  • On the day prior to each trial, participants were instructed to sleep for 8 hours.
  • On day one of each experimental trial participants woke at 06:00 h and arrived at the laboratory. After 30 h subjects performed a 30 minute pre-load treadmill run at 60% VO2 max followed by a 30 minute self-paced distance test. No fluids were consumed during the pre-load or distance test. Between the pre-load and distance test subjects were removed from the treadmill for 15 min to allow for blood and saliva to be collected.
  • Prior to the distance test participants were instructed to run as far as possible in 30 minute and to control the speed of the treadmill (gradient set at 1%). During the distance test participants only had information about elapsed time. Total distance was recorded.
  • During the pre-load, minute ventilation, O2 uptake (VO2), CO2 production (VCO2), respiratory exchange ratio (RER), heart rate (HR), core temperature, and skin temperature by chest, upper arm, thigh, and calf thermistor probes were measured continuously. Ratings of perceived exertion (RPE) were obtained at 5 min intervals.
  • During the distance test, core temperature, skin temperature and HR were measured continuously RPE and speed was recorded at 5 min intervals.
Statistical Analysis:
  • A one tailed paired t-test was used to determine the effect of sleep deprivation on time trial performance and resting core temperature.
  • Fully repeated measures ANOVA (trial x time) with Post hoc Tukey’s HSD or Bonferroni adjusted t-tests were used, where appropriate, to determine the effect of sleep deprivation on physiological and perceptual responses during the pre-load and distance test.
  • Significance was accepted as P < 0.05.

Study Strengths / Weaknesses:

One limitation of this study was the small size of the trial groups. However, the authors used a crossover design, which strengthens the results due to the fact that each subject underwent each condition. In addition, the authors investigated many of the pertinent variables that could contribute to reduced performance under conditions of sleep deprivation.

In addition to the small size of the trial, only young male participants were included which limits the applicability of the results of this study to women and older adults. As with all research, more investigation is needed to further clarify the mechanisms involved in sleep deprivation and performance.

Additional References:

  1. Pickett GF, Morris AF. Effects of acute sleep and food deprivation on total body response time and cardiovascular performance. J Sports Med Phys Fit 1975; 15:49–56
  2. Martin BJ. Effect of sleep deprivation on tolerance of prolonged exercise. Eur J Appl Physiol 1981; 47:345– 354.