Hey, sorry for the long time to reply, I was putting my strategy to the test at the Cozumel 70.3… and then I enjoyed the beaches and snorkeling for a week.
I haven’t done a lab sweat test to determine my needs, but I used the questionnaire from Precision Hydration to estimate it, and then I’ve refined it on long rides and at events.
What I can tell you is that based on what I see other people do, versus what I seem to need, I am probably on the tippy top of high volume, salty sweat. Part of that is probably my weight right now (210lbs), which could use some adjustment but it will take some time to get back to what’s been my best racing weight (185lbs). But even when I was lighter, I put out a lot of sweat very easily.
Here’s what I can say after last Sunday: it’s really hard being a heavy sweater in a hot, humid race. It was so hot and humid (and honestly, even starting the race fully hydrated was challenging, because you sweat a lot without doing anything!), I went through: 1- my 28oz BTA bottle, 2- two 24oz bottles in my triangle (all of these had 10g carbs and 166mg sodium per 4oz liquid), 3- one package of Clif Bloks, 4- three bottles of Gatorade handed out on course (not Gatorade Endurance unfortunately), 5- a bottle of water handed out on course that I didn’t drink, but poured on myself to cool down. I was on course to do a bit better, like 2:50 or so, but I have some lingering fit issues and couldn’t hold my TT position the whole time.
I ended the bike starting to cramp hard, and I spent the first few km of the run walking while taking salt pills with water at the water stops. After I’d gotten 4-5 salt pills in (so 800-1,000mg sodium), the cramps started to ease up and I felt better. If I’d been able to get more of that sodium on the bike, instead of drinking the relatively low-sodium Gatorade, I would have been in better shape, I think.
In the future I think I will stick with my first three bottles as described (I use EFS Pro, 1 scoop per 4oz water), but I will have some of Precision Hydration’s high-sodium tablets to add to water I pick up on the course. I was also hitting about 80g of carbs per hour, and I have no complaints about that but I might throw in a second package of Clif Bloks to bring me up to 95g/hr.