How Sleep Impacts Strength Gains, and What We Can Do About It

A research review from the Performance Digest

Background & Objective

Sleep deprivation and sleep restriction both increase fatigue and decrease readiness for training. At present, there is limited knowledge surrounding the effects of inadequate sleep on strength performance. Therefore, the aim of this systematic review is to understand the effect of sleep deprivation and sleep restriction on resistance training performance and to explore the effects of inadequate sleep on hormonal responses and markers of anabolism.

What They Did

The authors performed a systematic review which included studies based on three combined concepts: 1) inadequate sleep, 2) resistance exercise, and 3) performance and physiological outcomes.

What They Found

With regards to acute sleep deprivation (e.g. one night with no sleep), there seems to be no significant detrimental effect on muscle strength. Moreover, there also seems to be no alterations in the cortisol-testosterone profiles following acute sleep deprivation. However, studies investigating chronic sleep deprivation (i.e. 30-64 hours of no sleep) found mixed results. For example, two studies observed a reduction in strength, and one study reported no differences in strength in comparison to a control group.

Practical Takeaways

Acute sleep deprivation (e.g. one night with no sleep) appears to have no detrimental effect on strength; though there is limited research on this topic. On the other hand, extended sleep deprivation does seem to have a harmful effect on strength, with consecutive nights of reduced sleep affecting multi-joint strength.

Napping before resistance training sessions and changes in training schedule (e.g. late starts) can be effective strategies for minimising the impact of sleep deprivation on performance during periods of inadequate sleep. Lastly, group training and the consumption of caffeine can increase resistance training performance; however, care must be taken with caffeine intake if athletes are training late in the day (i.e. mid-afternoon onwards) as caffeine can negatively impact sleep.

Reviewer’s Comments

The authors of this study highlight a particular scenario in which athletes are likely to be subject to sleep deprivation – the birth of a new child. I can relate to this scenario as a lot of my athletes have had to deal with sleep restriction/deprivation as a result of newly-born babies. Some other scenarios that may lead to inadequate sleep include important competitions, especially for novice players, school and work-related stress, jet lag, and higher than usual training load. Practitioners must be able to identify these types of scenarios (e.g. inadequate sleep) and implement counteractive strategies such as:

• Adjust resistance-training loads
• Adjust the training schedule (e.g. late starts or
  inclusion of napping opportunities)
• Implement competition within training sessions
  (e.g. competition in some exercises)
• Pre-training nutritional strategies (e.g. caffeine
  intake)
• Training in groups

Although research is limited regarding the hormonal responses to sleep deprivation, it seems that chronic sleep restriction may lead to an inappropriate hormonal environment for adaptations to resistance training. Further research is needed to better understand the effects of inappropriate sleep on anabolic responses. Moreover, it would be interesting to explore the effects of inadequate sleep on muscle activation.

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The full study can be read here.