Sleep & Recovery: The Underrated Success Factor

The Third Pillar

Training provides the stimulus, nutrition supplies the building blocks — but the actual adaptation happens during recovery. Sleep is the most important factor in this process.

What Happens During Sleep?

Hormonal Processes

• Growth Hormone (HGH): 70-80% of daily secretion occurs during deep sleep, particularly in the first sleep cycles (Van Cauter et al., 2000).
• Testosterone: Even moderate sleep restriction can measurably lower testosterone levels. Leproult & Van Cauter (2011) showed that consistently getting too little sleep can reduce testosterone in young men by 10-15%.
• Cortisol: Chronic sleep deprivation raises cortisol, which has a catabolic effect and promotes muscle breakdown.

Muscle Recovery

During sleep, the body repairs microtrauma in muscle tissue and synthesises new proteins. Sleep deprivation measurably impairs these processes (Dattilo et al., 2011).

Effects of Sleep Deprivation

A study by Mah et al. (2011) on Stanford University basketball players demonstrated impressively what optimal sleep can achieve:

After increasing sleep duration to 10 hours for 5-7 weeks:

• Sprint time: 0.7 seconds faster
• Free throw accuracy: +9%
• 3-point shooting: +9.2%
• Reaction time: significantly improved

Conversely, sleep deprivation shows negative effects:

• Increased injury risk (Milewski et al., 2014: adolescents with <8h of sleep had a 1.7x higher injury risk)
• Reduced glucose tolerance and insulin sensitivity
• Increased hunger and appetite for calorie-dense food

Optimal Sleep Duration

The National Sleep Foundation recommends 7-9 hours for adults. Physically active individuals often benefit from the upper end of this range.

Individual differences: Genetics influence sleep needs. The DEC2 gene enables some people to function with less sleep — but these individuals are extremely rare (<1% of the population).

Improving Sleep Quality

1. Light Exposure

Morning: Bright light exposure (ideally sunlight) within the first 30-60 minutes after waking stabilises the circadian rhythm (Blume et al., 2019).

Evening: Blue light from screens suppresses melatonin. A study by Chang et al. (2015) found that reading on an iPad instead of a book delays sleep onset and melatonin secretion.

Recommendation: Dim screens or use blue light filters 1-2 hours before bedtime.

2. Temperature

The optimal sleep temperature is 16-19 degrees C. The body needs to lower its core temperature to fall asleep. A cool room supports this process (Okamoto-Mizuno & Mizuno, 2012).

3. Caffeine Timing

Caffeine has a half-life of 5-6 hours. A study by Drake et al. (2013) showed that caffeine consumed even 6 hours before bedtime reduces sleep quality.

Recommendation: Last caffeine before 2 PM (assuming a 10 PM bedtime).

4. Consistency

The circadian rhythm benefits from regularity. Go to bed and wake up at the same time every day — including weekends.

A study by Phillips et al. (2017) on Harvard students found that inconsistent sleep times correlated with poorer academic performance, even with the same total sleep duration.

5. Avoid Alcohol

Alcohol may help with falling asleep, but it fragments sleep and suppresses REM phases (Ebrahim et al., 2013). Sleep quality suffers considerably.

Sleep Tracking

Wearables can create awareness of sleep patterns. However, the accuracy of sleep stage detection is limited. Use them as a rough indicator, not as an absolute measure.

More important than data are subjective indicators:

• Do you feel rested?
• How is your training performance?
• Do you need an alarm clock to wake up?

Strategic Napping

Short naps (10-20 minutes) can improve performance without disrupting nighttime sleep (Lovato & Lack, 2010).

Rules:

• Maximum 20-30 minutes
• Not after 3 PM
• Not as a substitute for nighttime sleep

Training and Sleep

Evening Training

Contrary to older recommendations, research shows that moderate exercise up to 1-2 hours before bedtime does not negatively affect sleep (Stutz et al., 2019). High-intensity training, however, should be finished earlier.

On Sleep-Deprived Days

On days with poor sleep:

• Reduce training intensity
• Consider reducing volume
• Watch for signs of injury

Conclusion

Sleep is not negotiable. 7-9 hours of quality sleep is an investment in health, performance, and body composition. Optimise light exposure, temperature, caffeine timing, and consistency — the effects are well supported by science.

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Sources:

• Mah CD et al. (2011). The effects of sleep extension on the athletic performance of collegiate basketball players. Sleep.
• Leproult R & Van Cauter E (2011). Effect of 1 Week of Sleep Restriction on Testosterone Levels in Young Healthy Men. JAMA.
• Drake C et al. (2013). Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. Journal of Clinical Sleep Medicine.
• Chang AM et al. (2015). Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness. PNAS.
• Stutz J et al. (2019). Effects of Evening Exercise on Sleep in Healthy Participants: A Systematic Review and Meta-Analysis. Sports Medicine.