The science of the perfect night’s sleep
Good decisions, productivity and teamwork are all hindered by exhaustion. The cost to our development, lives, health and productivity is enormous.
“Many studies reveal the significant cost of employee presenteeism (reduced productivity due to attending work while physically or mentally unwell). A recent study based on Australian workers shows the association between poor sleep quality and quantity with higher presenteeism,” says Stuart Taylor, Founder of The Resilience Institute Australia.
Coordination, attention, decision making and impulse control all suffer, while cardiovascular risk, blood pressure, metabolic disorders (obesity and diabetes) and immune system dysfunction increase.
The Resilience Institute recently released the findings of a three-year study measuring the resilience of 16,000 people across 250 organisations. 43.3% of all respondents ranked highly on questions relating to tiredness and fatigue.
“Sleep and rest are vital to our health and wellbeing. Technology among other factors, has disrupted our body clocks and the first step to getting a good night’s sleep, is understanding the science behind it,” says Taylor.
Sleep is subject to biological clocks; our circadian rhythm is a 24.5 hour cycle built into the suprachiasmatic nucleus (SCN). Sitting just behind the eyes, this clock is paced and regulated by light, in particular, requiring blue light in the early hours of the day to effectively re-set.
Upon waking, our body temperature rises, cortisol is released, blood pressure rises, testosterone peaks and we are alert, coordinated and effective. During the day, we build up adenosine which in high levels increases our propensity for sleep. The longer we are alert, the deeper our delta-wave sleep. After 7pm our body temperature drops, at 9pm melatonin secretion begins and we drop into a deep sleep somewhere between 10pm and 2am. Growth hormone is active during this stage, facilitating repair, growth and immunity.
A good night’s sleep rejuvenates our cells, builds muscle and repairs the brain, while REM sleep (dreaming) is essential to memory and emotional intelligence.
Our suffering today is largely due to a disrupted circadian rhythm. We are perpetually desynchronised by artificial light, heating, electronics and sleep debt. We are not exposed to adequate blue light in the early part of the day.