Sleep and performance

A few weeks ago I attended the Sport Innovation (SPIN) conference and was lucky enough to hear Dr Charles Samuels present on the latest research in sleep and human performance. Dr. Samuels works at the Centre for sleep and human performance in Calgary Alberta.  As it turns out Canada is a world leader in understanding the effects of sleep on human performance.

Here is a summary of the note I took at the presentation;

Delay in the natural sleep phase causes athletes (especially teenagers) to stay up too late: too much stimulation late in evening/night and not enough light in the morning

Most important element in good sleep habits is a routine;

  • same bed time and waking time every day of the week
  • cultivate ideal sleep environment
  • high performance athletes need approximately 9 hrs of sleep on average. Minor deficits can be made up within 24-48 hrs

REM cycles dictate sleep – wake cycles

  • Cycles are 2 hours ± 30 min
  • Natural sleep duration multiples of REM cycle
  • Forcing waking in mid-REM leads to poor performance

Target exercise at optimal times re sleep habits

Adjust training schedule from 7 am workout to 9:30-10 am pushes sleep cycle back

No training within 3-4 hours of bed time keeps cycle from moving forward

Chronotype: Mid-range is most common

  • Bedtime 11-12 pm
  • Wake time 8-9 am
  • Nap time 2-3 pm (max 30 min)
  • Total sleep time: 9 hrs

Basic science of sleep: sleep is driven by fatigue debt that begins accumulating on waking

Three factors affecting sleep

  • homeostatic function: sleep quantity = sleep debt
  • circadian: sleep quality = minimal disruptions (internal or external)
  • ultradian: circadian timing = light exposure (10 000 LUX)
    • Key hormone: adenosine accumulates with increased sleep debt

Circadian physiology

Genotype dictates diurnal preference

Core temperature: lower core temp encourages better sleep early and late in sleep cycle. Core temperature lowest in deep REM sleep- Japanese layered quilts (early sleep thinner layers- deep sleep thicker layers, more thermal layering over core than extremities)

Melatonin secretion: related to light exposure, peak melatonin levels occur with lowest core temperatures

Phase adjustment: related to light exposure, modified by light therapy. Melatonin therapy is very risky and best left to sleep experts (not GP or sport MDs)

  • Light therapy: 30 min @ 10 000 LUX within 60 min of waking can push sleep cycle back

Amount of sleep

Determine true sleep needs: cover all clocks, no noise, no light, comfortable and go to sleep when tired and wake when ready. Repeat for 2-7 days to establish baseline

Factors affecting timing of sleep

  • Endogenous (physiology, fatigue, etc.)
  • Exogenous (noise, light, ambient temperature, humidity, barometric pressure, etc.)
  • Jet lag

Quality of sleep

  • Environmental factors (allergies, pollutants, chemical)
  • Sleep disorders
  • Actigraph: a  small sensitive 3D accelerometer worn to monitor sleep-wake cycle patterns

Jet lag

Begin adjusting 2 weeks earlier and allow four days after for smoothest transition

Sleep periodization planning

  • Sleep screening
  • Daily sleep log
  • Design a sleep program
  • Light therapy
  • Jet lag management
    • Awareness of sleep cycle
  • Learn what each athlete needs for sleep
  • Manage sleep debt on micro scale first, macro scale second
  • Minimize disruption of sleep-wake cycle
  • poor sleep requires help
  • rest and sleep important for active recovery
    • Sleep adequate? Don’t changing anything?

Sleep management

  • Limit exposure to TV and LCD screens in 2 hrs prior to sleep time
  • Includes video games
  • Computer screens
  • Anything mentally stimulating
  • Wind down before sleep time- quiet, relax

Insomnia/hypersomnia

  • Missing REM
  • Interrupted REM
  • Forced arousal (waking) = reduced test
  • Manipulate rhythm 30-40% resistance
  • Eating re sleep recovery
    • 4 hrs prior to sleep onset
    • Digestion affects sleep to same degree as performance

Injury

  • Post concussion
  • Insomnia an issue
  • Hypersomnia not an issue

RESOURCE TO READ

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