A sleep researcher thinks any time zone change for South Australia could leave the state with fewer ‘morning people’.
Professor Leon Lack of Flinders University said a shift to eastern time for SA would mean less sunlight in the mornings for many locals but more light in the evenings.
He said people might be more likely to go to bed later than they currently do, but then struggle to get up the next morning.
“I think it could well have impacts on the timing of people’s body clocks,” he said.
“The circadian rhythms, the 24-hour rhythms that we have internalised – are very much affected by exposure to bright light – and sunshine of course is the brightest light we can be exposed to.
“Having that sunshine delayed later in the evening, particularly in the summer time, will tend to have the effect of pushing our body clocks later in time.”
The South Australian Government released a report this week about its proposed time zone change, preferring a shift forward by 30 minutes to any option of shifting the time back by 30 minutes or more.
The report estimated a time zone change would benefit South Australia’s economy by as much as $2.5 billion annually.
Professor Lack said a time zone shift might come with a health cost.
“Quite a bit of research has been done to look at the differences between ‘evening’ types and ‘morning’ types in a range of different variables and some of those include difficulties with psychosocial adjustment in a broad sense,” he said.
“Sometimes that’s associated with mild depression, difficulties with increased sensitivity to pain and there are a number of what are considered to be deficits that are associated more with ‘evening’ types than ‘morning’ types.
“So that truism ‘early to bed, early to rise makes a person healthy, wealthy and wise’, there’s a little bit of truth to that.”
Professor Lack said shifting the time zone forward could make people less productive at work.
“Making mistakes in the first couple of hours in the working day, all of those things are difficult to cost, but nevertheless one would think it must have an overall impact on our society, not only in terms of health but in terms of economic outcomes,” he said.
But the researcher said it was not all bad news for ‘evening’ types.
“People who are ‘evening’ types tend to have a slightly better sense of humour than people who are ‘morning’ types, so maybe that will counterbalance to some extent increasing deficits as a result of becoming more of an ‘evening’ type person,” he said.