Daylight Savings Time-Itis

Daylight Savings Time (DST) is the practice of advancing the clock by 1 hour in spring and back by 1 hour in autumn to provide more daylight hours in the evening in summer.

The idea of DST has been attributed to Benjamin Franklin (who was worried about the economic cost of energy during dark evenings1), but apparently it was a Kiwi who first proposed the idea and it was adopted by Germany and Austria prior to World War 1 to preserve coal, and also adopted by the Allies. It fell out of favour in the years after the war, until the 1970s energy crisis  precipitated a return by the U.S. and other first world nations.  Today most countries in North America and Europe, which are located in higher latitude areas with seasonal variation in natural daylight times have DST (over 70 countries1), whereas most countries in Asia and Africa that are closer to the equator do not1.

The benefits of DST are said to be the increase in recreation time, alignment of work hours to sunrise, and decreased energy costs1.  While this may be appreciated by those living in cities, country folk have disagreed with the reduction in their early morning sunlight. Morning light is also important for other people, especially those with seasonal affective and bipolar disorder, and the twice yearly time shift may impact their wellbeing1.

Post Daylight Savings Syndrome?

I used to wonder about parents who lamented the changes in sleep and behaviour in their young children in the week(s) post DST.

It wasn’t until I became a Mum that I realised they weren’t ‘cray-cray’ and what I thought was an urban myth, might actually be a ‘thing’. In discussions with colleagues, patients and friends, I found a common thread in worsened sleep issues, fatigue, crankiness, anxiety and restlessness post daylight savings, which impacted mostly on the young (toddlers through to preschool, adolescents) and the elderly.

Much like the changes we notice in our kids in the lead up to cutting a tooth, there isn’t a lot of research to support the what some have coined ‘Post Daylight Savings Syndrome’ (PDSS).

It’s been suggested that in modern times with electrical lighting and our 24/7 existence that we have a sleep debt of 1-2hrs less sleep per night than our great grandparents2.

Accumulated sleep deprivation may impact on our perceptions, behaviours and decision making ability, contributing to anxiety, reducing cognition and increasing the incidence of accidents 2.  Our Monday to Friday routines are also often turned on their heads on the weekend with more alcohol consumption (which reduces sleep quality) and late nights adding to our sleep disruption.

Not surprisingly, more injuries occur on Mondays than any other day of the week 2.

Compound ordinary Mondays with an hour time adjustment for Daylight Savings Time.

Motor vehicle accidents peak in the days post DST (and this is more pronounced in the autumn time shift).

Heart attacks increase in incidence on Mondays. There is a modest peak on the Monday post DST in spring and reduction after the autumn times shift. This is thought to be related to a autonomic nervous system disturbance and increased inflammation3.

The stock market, which is traditionally lower at close of business on Mondays than Fridays (the ‘weekend effect’) has been found in a number of studies to be lower on the Monday post the introduction of DST but these studies are not all in agreeance, and some markets may be more resilient than others2.

The twice yearly change of DST impacts on sleep duration, quality and placement and these changes are more pronounced in the week after the change1.  The ‘spring forward’ of 1 hour is thought to be readily compensated by changes in an persons sleep/wake behaviour but the time it takes to fall asleep and incidences of broken sleep add to our ‘sleep debts’. The ‘fall back’ of 1 hour in autumn theoretically gives us one hours extra sleep but our habitual sleep patterns suggest this is not actually achieved1. Those that are already have shortened or fragmented night time sleep, such as the elderly may find it more difficult to adjust to DST.

Not everyone experiences ‘PDSS’ but the changes may be more negatively experienced by those with more established routines (children, elderly), those with pre-existing sleep issues or affective disorders.

5 PDSS Tips

  • If you can, work on improving your sleep quality in the lead up to the shift to DST
  • Allow yourself extra time in the morning by having breakfast/lunch/clothes etc prepared
  • Where possible, start and finish work at a slightly different time in the week post DST to ease yourself into the change
  • Be aware of everyone else’s sleep debt on the Monday post DST and take extra care on the roads.
  • Give yourself permission to have a ‘slower’ week than usual.


(1)         Harrison, Y. Sleep Med. Rev. 2012, 17.

(2)        Muller, L.; Schiereck, D.; Simpson, M.; Voigt, C. J. Multinatl. Financ. Manag. 2009, 19.

(3)         Sandhu, A.; Seth, M.; Gurm, H. Interv. Cardiol. 2014.

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