Last year at IM Western Australia, I got pretty badly sunburnt on the bike. It was 33 deg celsius. I was wearing a tri-suit that exposed a lot of my back, and despite lathering sunscreen on before and during the run, the damage had been done. I ended up with weeks and weeks of pain (blistering, weeping etc) and marks that have not even faded one year on.
Very interested to know if there is any research out there (or anecdotal evidence) on whether the effects of exposure to the sun could have had a detrimental impact on my run split....?