Effects of Exercise on Sleep Flashcards
Indicators of good sleep quality = can you use certain criteria? yes
Key indicators
* falling asleep in 30 minutes or less
* sleeping more time while in bed (at least 85% of the total time) = Sleep efficiency
* waking up no more than once per night
* being awake for 20 mins or less after initially falling asleep
* (National Sleep Foundation, 2019)
Sleep quality
- Fundamental to wellbeing
- Modifiable by biological factors + lifestyle = sleep quality + patterns modifiable = how? = diet, exercise
Physical activity (PA)
* An effective, non-pharmacological approach to improve sleep
* An alternative/ complementary approach to existing therapies for sleep problems e.g. insomnia
Three areas of focus:
* Acute PA
* Regular (chronic) PA
* Exercise intensity
Effects of physical activity on sleep
Acute physical activity (< 1 week of exercise) = is it effective = yes!
* Small effect sizes:
○ ↓ sleep onset latency (SOL) = fell asleep quicker after ex
○ ↓ wake after sleep onset (WASO)
○ ↑ sleep efficiency (SE)
○ ↑ total sleep time (TST), ↑slow wave sleep (SWS) –> ↓ sleep disturbances (Kredlow et al., 2015)
Regular physical activity (≥ 1 week of exercise)
- Small effect sizes:
○ ↑ TST, ↑ SE
○ moderate-to-large robust positive effects on PSQI subscales
○ (daytime sleepiness, sleep disturbance, sleep duration, sleep efficiency, sleep onset latency, sleep medication use)
Exercise intensity
Moderate activity
* Defined as below 3.0–6.0 exercise metabolic rates (METs) (3.5–7 kcal/min)
○ *MET - the metabolic equivalent of task
○ 1 MET = amount of O2 consumed while sitting at rest
Vigorous activity
* Defined as greater than 6.0 METs (more than 7 kcal/min)
American College of Sports Medicine (ACSM) guidelines
Exercise intensity and sleep
Positive results toward global sleep score by PSQI
* Menopausal women + high school students
○ An increase of walking distance by 500 steps per week showed positive effect in improving sleep quality = suggests that these people must be highly sedentary as 500 is not a lot
* Physically active + non-active:
○ Daily walking exercise beneficial to improve subjective sleep quality e.g. using PSQI questionnaire
* Community-dwelling elderly:
○ Tai Chi + home exercise, in a randomised controlled trial, improved sleep quality in exercisers than non-exercisers
When to exercise?
- “Moderate or vigorous exercise completed within 2 hrs of bedtime does not disturb sleep in most subjects” = exercise close to bedtime especially high-intensity = increase sympathetic nervous activity = may increase arousal = for people w/ insomnia when they have increased arousal = increases cortisol peaks during the sleep period
- Discourage high-intensity exercise within 2 h of bedtime, especially for those with insomnia - potential hypothalamic pituitary axis (HPA) activation (authors’ hypothesis).
○ ACSM’s Health & Fitness Journal Volume 22(2):23-29, 2018. Markwald et al. - “Evening exercise may positively affect sleep, but vigorous exercise might impair sleep-onset latency” (Stutz et al, 2018)
Exercise – the most helpful behaviour for promoting sleep in insomnia
Epidemiological studies:
* Regular light, moderate, or vigorous exercise or increased daily physical activity levels associated w/ better sleep + decreased risk of insomnia (Markwald et al. 2018. ACSM’s Health & Fitness Journal)
* Aerobic exercise of moderate or high intensity, or acute + chronic resistance exercise:
○ Both associated w/ significant improvements in sleep in individuals w/ insomnia
Exercise – the most helpful behaviour for promoting sleep in insomnia
Experimental studies
* Morning vs Evening exercise
* Acute physical exercise:
○ Did not improve subjective sleep quality (questionnaire)
* Acute morning exercise:
○ ↓ arousal from sleep over the whole night (polysomnography)
○ ↓ number of wake stages during the 2nd half of night (polysomnography)
(Morita et al., 2017)
* Morning exercise is better than evening exercises for people w/ insomnia
