The other day my father emailed me some advice from a gym buddy of his that has ended up in the medical tent at the end of the Seattle Marathon three times:
It seems that the weather is so damp and cold that you do not feel you need to replace fluids (and he has done dozens of tris and marathons – including the Canadian Iron Man) and the result is that he would finish both dehydrated and hypothermic – so off to the tent for warm fluids to be pumped in.
I’ve noticed that I have indeed been drinking less as the temperature has dropped, but I think I’m still getting enough.
I also just read this excellent article by Matt Fitzgerald about nutrition and hydration for half-ironman distance races. Â I found the math interesting, as he recommends taking in 60 grams of carbs per hour, and letting your own thirst dictate your hydration.
As I’ve noted, I use Hammer Gel for nutrition and nuun for hydration. Â I was already only drinking whenever I felt thirsty (about every 10 minutes), and through experimentation settled on a gel pack every 45 minutes (but no fluid for 10 minutes before or after the gel, or else I get a side stitch). Â The math adds up to about 53 grams of carbs per hour.
I love it when what I’ve figured out on my own is corroborated by the experts.
Correction (11/4/2010): actually, the math adds up to 29 grams of carbs per hour. Â I’m not sure what happened there, but it in any case, it looks like I’m only getting about half the recommendation. Â Maybe I’ll need to look into alternating nuun (which has 0 carbs) with a sports drink, as I don’t think I can digest twice as much gel while running (and that’ll get expensive in a hurry!). Â Dangit.