Why is sleep important?

By Dr Paul Huang
Respiratory & Sleep Physician at the Victorian Rehabilitation Centre
Medical Director of Victorian Rehabilitation Sleep Laboratory

Everyone has experienced the malaise one feels after a poor night's sleep, whether it be from caring for a sick child, after a late-night out, or even after lying awake stressed about an important event to come. For most, this is a rare occurrence, but 20-35% of the population report daily or near-daily inadequate sleep, difficulty falling or maintaining sleep, daytime tiredness or irritability.¹ Society's increasing reliance on electronics and our ever-increasing inability to disconnect from work and social media has further negatively impacted our sleep quality.

Sleep is inadequate when an individual cannot maintain adequate alertness or function. Insufficient sleep is often due to short total sleep time or sleep fragmentation. Poor sleep is associated with an increased risk of motor vehicle accidents, sub-optimal daytime performance, and many health complications, including hypertension, cardiovascular disease, and obesity. Extensive epidemiological studies have demonstrated that less than 5 hours of sleep predict increased mortality. Interestingly, more than 9 hours of sleep also predicts high mortality, with longer sleep duration potentially indicating the presence of other comorbidities. Therefore 6-8 hours seems to be the ideal sleep duration.²  

Not only is insufficient sleep associated with physical sequelae, but poor sleep can also contribute to low mood and depression. Optimising sleep quality may help improve depression.

About half the cases of poor sleep can be attributed to sleep disorders. Sleep apnoea and insomnia alone collectively affect approximately 10% of the population. Common sleep disorders include obstructive sleep apnoea (OSA), restless legs syndrome (RLS) and insomnia. OSA, in particular, is one of the most readily treatable sleep disorders, and the initiation of therapy improves sleep quality, daytime energy levels, mental alertness and quality of life.

When to seek help?

• Feeling unrefreshed, poor energy levels or concentration during the day
• Sleepiness when driving
• Snoring or pauses in breathing overnight (often reported by the partner)
• Socially disruptive snoring
• Symptoms of restless legs
• Dream re-enactment or complex behaviours whilst asleep
• Persistent difficulties falling or staying asleep
• Patients with a history of cardiac disease, stroke, obesity, diabetes or poorly controlled hypertension are at high risk for sleep apnoea and should also be screened by their general practitioner.

If you have any of the above symptoms, please contact your general practitioner or Sleep Physician. The good news is that many sleep disorders are easily diagnosed and managed, and initiation of treatment can make a significant difference to your quality of life, energy levels and, of course, your quality of sleep.

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1. Hillman DR and Lack LC. Public health implications of sleep loss: the community burden. Med J Aust 2013; 199 (8): S7-S10. || doi: 10.5694/mja13.10620

2. Cappuccio FP, D'Elia L, Strazzullo P, Miller MA. Sleep duration and all-cause mortality: a systematic review and meta-analysis of prospective studies. Sleep. 2010;33(5):585-592. doi:10.1093/sleep/33.5.585