Health risks of daylight saving time

Paul Eggert eggert at CS.UCLA.EDU
Thu Mar 29 18:59:20 UTC 2007

Since the subject of health risks is in the news....

The main health effects of DST that I know of are the following.

 * Extra afternoon daylight may encourage people to exercise more,
   which should be a big win.

 * Sunlight triggers vitamin D synthesis, but overexposure leads to
   skin cancer; so whether DST helps or hurts here depends on your
   latitude and daily schedule.

 * DST may be helpful in fighting some forms of depression:

      Henry Olders (2003-08-13). "Average sunrise time predicts
      depression prevalence". Journal of Psychosomatic Research 55
      (2): 99-105. DOI:10.1016/S0022-3999(02)00479-8.

   Some argue the reverse, though.

 * DST can help night-blindness sufferers, though it can also hurt:
   it depends on their schedule.

 * DST's clock-changes temporarily disrupt the sleep cycle, which can
   lead to suboptimal decisions (e.g., while driving, or while trading
   stocks).  There have been several studies of these secondary
   effects, but I know of no studies of any direct health risks.

So the vast majority of this stuff is speculative and/or anecdotal;
there's only one scientific study that I know of.

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