Sleep can be one of the most overlooked aspects of training but the reality is sleep (or recovery) is one of the biggest components of seeing progress along with nutrition and training. The nature of some sports today (hockey & soccer come to mind first) is that these athletes may have multiple games in a day (anywhere from 3-5 games in a 2-3/day period). Consequently, adequate recovery is essential to maintain healthy psychological, physiological, & performance qualities. One great blog to read on this topic comes from Patrick Ward. Rest, Recover, Regenerate Part 1: Overtraining Syndrome.
One study I came across, describes the effects that a lack of sleep can have on athletes muscle recovery and performance. It can be found here. Some of the key points were.
- Athletes performed a graded exercise run (GXR) @ 60, 70, 80% of their VO2peak on a treadmill, followed by a 50 minute intermittent sprint exercise (ISE) that included 50 x 15m maximal sprints interspersed with by fast running, jogging, walking, and plyo bounds. (Sprints & bounds were maximal while the others methods were done at each individuals desired pace)–this was done over a 2 day period.
- The control (CON) group was allowed to leave after the first days training session, while the sleep deprivation group (SLDEP) had to remain in the laboratory after and were deprived of sleep that night. So when the second training session started the SLDEP group had 32 hours since awakening from their last sleep. Food was provided for all these individuals.
- No caffeine was allowed 24hr prior or during any of experimental trials
- Mean sprint time for intermittent sprint performance (ISP) = signficantly slower on day 2 compared to day 1 during both CON and SLDEP trials.
- Significant decrease in sprint performance and the distance covered during hard running on day 2 compared to day 1 for both CON and SLDEP.
- SLDEP group resulted in significant decrease in bounding distance and mean performance of the first 10 sprints during day 2.
- Muscle voluntary contraction (MVC) pre exercise on day 2 was significantly lower for SLDEP group compared to CON group.
For the first time, we show that sleep deprivation has a negative effect on the day to day recovery of leg strength/power and sprint performance during simulated team-sports performance. Sleep deprivation also tended to have a negative effect on self-selected exercise intensities (pacing strategies). These differences in performance are not explained by differences in blood lactate, electrolytes, CK, heart rate or core temperature as these were similar between trials. However, we show that sleep loss retards the repletion of muscle glycogen and may be responsible for the greater decline in performance on the second day. Accordingly, the reduction in muscle glycogen and increased psychological strain prior to exercise may result in the reduction of voluntary muscle recruitment noted in MVC and thus be responsible for the slower pacing strategies and reduced performance noted following sleep loss. The current findings indicate that strategies should be used to ensure adequate sleep occurs between competitive events as this could affect some aspects of athletic performance and muscle recovery. Additioanlly, future research should also investigate possible nutritional or other complimentary strategies that may also aid in recovery from impaired sleep.