Sweating the details

I'm a bit behind on posts about last weeks training, I'll catch up over the next few days.

A month or so ago, I read one of whyiron s posts about using the RunFar Cycling Time as a sweat test, taking along scales and weighing in before and afterwards. What a great idea! Normally my rides are punctuated by eating, especially the recent Austin 70.3 course rides where we've gone for lunch afterwards and even where not I have to eat during the long rides.

So I planned to do my last TT , go for a warm-up, race the TT, then go for a warm-down and weigh myself over about an hours workout. Never happended. I arrived late as I couldn't get away from work. Quickly changed into my cycling gear, stood on the scales with a full water bottle, my weight before the ride 211lbs.

I bolted off and did my first loop hard, as fast as I could, I got back in 21:21, 18-seconds short of a PR, but respectable. I'd been up early and swam at Barton Springs with Tune. After the first lap I did a steady second lap. When I got back to the car, I removed shoes, helmet and glasses, holding what was left of my water bottle. After 16.2-miles of cycling, just 47-minutes of exercise, I was down to 207.5lbs. I did a double check and yep that was it. I'm not sure what I expected but that was way more. Heck the scary thing was, it wasn't even that hot that evening.

The sweat calculator tells me my sweat rate is 71.5 oz/hr or 2.03L/hr. By comparison, whyiron  is 49.2oz/hour. That means I should be drinking 3x 750ml per hour. Given my Austin 70.3 rides are sometimes done on just 3x 750ml bottles total that perhaps explains my problems on the run and possibly my joint issues at HIM and longer. The question is though, is it possible to actually drink that amount on the bike? That would be nine bottles for a 3-hour bike.

What the sweat calculator also confirmed, is what I'd previously learn in my heat tank tests back in 2004. Studies show a maximum carb absorption rate of 100g/hr or about 400 calories per hour. To keep up with my energy needs, I would have to take-in 162g of carbs per hour or 650 calories. The problem is, those with a high sweat range should stick to the low end of the scale, or in my case would leave me 40g of carbs or 200 calories per hour down, multiple by 5x for a HIM and there you have my problem, bonk central.

In the TT, I got 3rd in my AG, AVG 22.5MPH and 39th overall. Tune put in a great effort, improved again and for the first time beat me by 6-seconds, fastest in her age group and 4th fastest overall. Nice!
I always find it helpful to hydrate 24-48 hours prior to a race or hard workout. I sweat a lot too (never calc the rate, though) and feel like that's the only way I can overcome having to drink so much liquid while exercising.
Ah that amount of bottles
You'd probably be better off with a camelbak.