An old friend informs me (and he would know – he swam the 10K at the 2008 Olympics) that the dehydration I experienced in Miami may have been more perceived than actual. Saltwater in the mouth and throat can induce craving for fresh water even when your body is adequately hydrated. More important, he suggests, is energy. While I did stash a gel pack in my suit (and consumed it at the 5K mark), he says he’d actually take 3 or 4 during a 10K.
In any case, don’t drink the saltwater!
One important issue I didn’t mention in my race report is chafing. I didn’t mention it because, I suppose, it’s one of the few things I did right that day.
Saltwater is highly abrasive, and without preventive measures you can develop some nasty irritation – even on a short, half-hour swim. Anywhere your skin rubs together – especially in the armpit region – is vulnerable.