We generally spend about a third of our lives doing it, but as members of the general public, we know surprisingly little about sleep.
Although we all know that lack of sleep can impact on mental alertness and reaction time, less well known is the fact that prolonged sleep deprivation is also linked to increased risk of high blood pressure, diabetes, obesity, depression, heart attack and stroke. About 20% of all serious car crashes are linked to driver fatigue.
Data collected from the Australian Antarctic Program over a 17 year period revealed that 40% of health events listed as “mental health disorders” were classified as disorders of sleep, commonly due to the prolonged austral summer daylight or austral polar night and the unique polar environment. (R. Watzl, P. Gormly & J. Ayton Australian Antarctic Health Register, AAD)
A number of wintering expeditioners at all three of our continental stations are currently participating in a research study funded by NASA and conducted by Monash University as well as the Brigham and Women’s Hospital and Harvard Medical School in Boston. The study also involves wintering staff at Halley Station (British) and Zhong Shan (Chinese).
The research aims to test an integrated program to assess sleep, circadian phase, cognitive functioning, behavioural health and safety in isolated and confined environments.
Circadian rhythms are the natural 24-hour cycles in our ‘body clock’ and include amongst other things blood pressure, body temperature, blood fats, sleep and melatonin production, a key sleep-inducing hormone which is produced primarily at night. Although circadian rhythms are “built-in”, they are adjusted to the environment by external cues particularly hours of daylight.
Those participating in the study have agreed to keep a daily sleep-work diary recording their time asleep, work shifts and any countermeasures to combat fatigue such as caffeine intake.
They will also fill out a fortnightly safety survey, do a monthly 48-hour urine collection to check melatonin levels, and undergo performance tests looking at reaction time, memory, learning, logic etc. The project also includes the use of high tech “wrist-watches” which are worn by expeditioners and detect ambient light, movement and sleep. The data is downloaded on station and sent by the station doctors to the researchers to analyse sleep patterns and duration. Expeditioners will also fill out monthly questionnaires and surveys on issues such as work relationships, moods, group cohesion and changes due to seasonality.
The next stage of this project being planned for subsequent winters and summers is an intervention in lighting at our stations. In conjunction with Monash and Harvard University, industry partners and the AAD, we hope to change the ambient light sources in living areas on station to a cycled variable wavelength light (e.g. blue wavelength light) which can restore sleep cycles by altering the body’s melatonin production.
Those fortunate enough to travel across the skies on some long haul flights will have experienced the blue wavelength lights and dimming procedures used to assist passengers to sleep. The lights we plan to use will emit the required blue wavelength but will look white, and be automatically cycled to restore circadian rhythms and sleep, thus preventing fatigue and adverse health outcomes.
It is great to see the enthusiasm and participation in this project which will inform future expeditioner health and well being and will also inform other similar situations like long term missions to Mars.