Speaker Reportr
Sleep, Health and 24/7 Living
Professor Phillippa Gander PhD, FRSNZ, ONZM
Professor Gander is a sleep scientist at Massey University – her opening comments reflected on having to cut her recommended sleep short to arrive on time!
Her talk covered the importance of sleep: Why we sleep, How much sleep do we need, Why do we sleep at night, and the challenges affecting sleep in 24/7 living.
So, why do we sleep?
The brain needs to go offline for essential recovery and maintenance. While in sleep mode, the brain goes through a complex series of processes during which it reconfigures itself and allows us to wake up with an updated version of ourselves. Memories are consolidated, tissues undergo repair, growth hormones - particularly in babies and children – are activated, immune systems are recharged and metabolisms regulated.
If our sleep is restricted in any way and for any length of time, we are likely to feel sleepier, experience irritability, have degraded alertness, poorer coordination, slower reaction times, and less success with creative problem solving.
We are also likely to experience uncontrolled sleep. You know the kind – sit down in front of the TV to watch the news (after a hard day at the office or on the golf course) and with in a few minutes ZZZZZZZZZZZZ …. Whatever you may think, uncontrolled sleep is beyond voluntary control!
The good news is that our lack of sleep does not accumulate - normal sleep rhythms can be restored within at least 48 hours where sleep is unrestricted.
Most adults need an average of between seven and nine hours sleep per night. Our averages change over our life time. For instance, a 0 – 3-month old baby sleeps an average of 14 – 17 hours; a 3 – 5 year old averages 10 – 13 hours, and at 65+ we average 7 – 8 hours. Less sleep or poor sleep patterns are linked with conditions including obesity, impaired glucose tolerance, Type 2 Diabetes, high blood pressure and heart disease.
We operate on a circadian master clock - the pacemaker in our brain regulating functions and daily rhythms. It allows us two windows for sleep – an afternoon nap and longer sleep at night. Not surprisingly we have a wake mode and a sleep mode, and we can track light through closed eyelids. Sleep windows are programmed into our brain.
We are most sleepy during our circadian low (11pm – 7am). It is also the time when our body temperatures are at their lowest, when we are least functional, and when fatigue-related errors are most likely. There is a high relationship between fatigue and road crashes – statistics show fatigue-related crashes occurring mostly between 4am-5am.
Phillippa reported that shift workers have challenges in adjusting to changes in their sleep patterns and find it difficult to stay asleep after lunchtime.
Ros Fogel
Club Reporter