Sleep disruption has a variety of causes which can include stress, anxiety as well as a condition called sleep apnea.
Lack of quantity and quality of sleep has profound consequences, which range from attention deficits, reduced concentration and mental processing, mental fatigue, as well as mood disorders, such as depression.
About 70 per cent of North American adults report having trouble sleeping.
However, exercise has been shown in past studies to help people attain better quality of sleep and recently more information about the relationship between sleep and exercise has been discovered.
To explore the relationship between sleep and exercise, it would be beneficial to briefly look more closely at the components of sleep. Sleep is not one single event – it is made up of a number of phases, and each phase is independently important.
The most important phase for the repair and maintenance of the body is called “slow wave sleep.” If this phase of sleep is interrupted, the body cannot fully repair itself and this may lead to fatigue, decreased function and illness during waking hours.
REM sleep has a number of phases and this is when dreaming occurs.
A condition called sleep apnea is a sleep disorder which affects about 15 per cent of the population.
Beyond the typical cognitive and physical problems associated with sleep disruption, sleep apnea can also lead to diabetes, cardiovascular disease, depression and early mortality.
Features of sleep apnea include snoring, interrupted sleep, severe breathing disruption and is associated with obesity.
A study published in the journal Sleep in 2011 found that exercising four times per week for 12 weeks improved sleep quality and reduced symptom severity in those with obstructive sleep apnea.
The interesting fact about this study was that improvements in sleep were obtained without any reduction in weight loss – the effects of exercise alone were enough to improve quality of sleep.
The type of exercise employed in this study included 150 minutes of aerobic exercise (primarily treadmill walking at 60 per cent of maximum capacity) distributed over four days per week and during two of those days a series of weight training exercises were performed which includes two sets of 8-10 repetitions of eight exercises.
In another study published in the Journal of Clinical Sleep Medicine in 2013, researchers sought to explore the relationship between sleep and exercises further.
The subjects were sedentary people diagnoses with insomnia, all in their 60s. The program consisted of 16 weeks of moderate intensity aerobic exercise (treadmill or stationary bike) for 30 minute sessions, three to four times per week.
The subjects, on average, slept 45-60 minutes longer each night by the end of the 16 weeks.
They also reported waking up less during sleep and had more energy and mental focus each day.
The interesting feature of the study was that for the first half of the study (two months) participants reported no benefit in sleep after exercising earlier the same day.
In addition to that, they reported exercising for a shorter duration on the days after having a poor night’s sleep.
This illustrates the feedback loop of how poor sleep causes next day fatigue, which causes exercise avoidance causing further sleep disturbance.
However, researchers noted that as participants maintained their exercised routines for the full four months that sleep had improved.
The main conclusion of this study was that despite not receiving any improvement in sleep over the initial weeks of exercise, with persistence, quality of sleep was improved by the fourth month
– Kerry Senchyna is the founder, owner and president of West Coast Kinesiology since 1992 and is a provincially registered kinesiologist (BCAK). He provides active injury rehabilitation, ergonomic assessments as well as elite athletic conditioning programs for clients.