Marathon runners spend considerable time outdoors training for and participating in
marathons. Outdoor runners may experience high solar ultraviolet radiation (UVR) exposure.
South Africa, where running is popular, experiences high ambient solar UVR levels that may
be associated with adverse health effects. This feasibility study explores the use of personal
dosimeters to determine solar UVR exposure patterns and possible related acute health risks
of four marathon runners during marathons and training sessions in Cape Town and Pretoria.
Runners running marathons that started early in the day, and that did not exceed 4 hours,
yielded low total solar UVR exposure doses (mean 0.093 SED per exposure period run,
median 0.088 SED, range 0.062 – 0.136 SED; average of 16.54% of ambient solar UVR).
Training sessions run during early morning and late afternoon presented similar results.
Several challenges hindered analysis including accounting for anatomical position of personal dosimeter and natural shade. To assess health risks, hazard quotients (HQs) were calculated
using a hypothetical runner’s schedule. Cumulative, annual solar UVR exposure-calculated
acute health risks were low (HQ = 0.024) for training sessions and moderate (HQ = 4.922)
for marathon runs. While these data and calculations are based on 18 person-days, one can
measure marathon runners’ personal solar UVR exposure although several challenges must