I cramp easily in hot weather so I wanted to get a rough idea of fluid replacement. I weighed myself before a run. It was a 45 minute recovery run 70 degrees very light effort. I was very surprised to find I lost 2.8 pounds so the following day I did it again in case I made an error. The next day was warmer but not hot 80 degrees, breeze, 67% humidity on a shaded forest path. I ran a medium pace for 50 minutes and lost 4.6 pounds! That’s about 88 ounces an hour! That seems crazy high like I have some type of diuretic hormone imbalance. Anyone herd of this kind of water loss and how you can deal with it?
ive known guys to lose 7-10 lbs after 2hr45min swim workouts and never have a problem with cramping, so i dont know if this form of measurement is really an accurate way, but i dont really know a better way, are you weighing right after the run or the next day was a little confused by the post.
Immediately before the run then immediately after. No urinating.
Welcome to the club!
I am 200 lbs. and can easily drop 6-7 lbs. an hour running in 80 degree temps.
To date, my four Ironman finishes have been in daytime highs no higher than 70.
I look gloomily at the 80 degree high predicted by the Weather Channel for Sunday’s Lake Placid Ironman. Don’t know what to do aside from going it slow, although even then I doubt that my fluid replacement efforts will keep up.
I’ve only done one IM. IMWI 05. It was in the 90’s 25 mph winds. I looked like I was covered in chaulk dust from all the salt left on my skin after evaporation. When I started walking the marathon I looked like a poster boy for kwashiorkor with a distended abdomen. I felt like I was filled up to my throat with liquid and it was sloshing in my stomach like a camelback and I was still thirsty. It was just not processing. I ended up walking about 40% of the marathon. I finished but would not want to go through that again.
I cramp easily in hot weather so I wanted to get a rough idea of fluid replacement. I weighed myself before a run. It was a 45 minute recovery run 70 degrees very light effort. I was very surprised to find I lost 2.8 pounds so the following day I did it again in case I made an error. The next day was warmer but not hot 80 degrees, breeze, 67% humidity on a shaded forest path. I ran a medium pace for 50 minutes and lost 4.6 pounds! That’s about 88 ounces an hour! That seems crazy high like I have some type of diuretic hormone imbalance. Anyone herd of this kind of water loss and how you can deal with it?
Two weeks ago it was 9.5 LBS in a 12 mile run at night with 85 degrees & fairly high humidity. Last week I lost 10.5 lbs total on a 45 mile ride in the heat. Plenty of world class sweaters on this forum.
JJ
At least it’s good to know I’m not the only one.
I’m in the same boat. Honu last year, lost 9 pounds, from 150 to 141. And that was after I rehydrated and got back to the room. But I was out of it. A few weeks before that I lost 7 during a training run. I commonly lose 6-7. I have come to the conclusion I carry more water to be lost.
Im 6’1" at about 175. I lose 90+ oz per hour if its really hot.
Stop looking at the weather for IMLP, it means nothing right now. Last year the Sunday morning paper forecasted a 10% chance of rain and partly cloudy skies.
Everybody is different. During my 20-24mi long runs I manage to loose up to 10lb (weigh only 155lb). I think that when you do it on weekly basis your body gets use to it. I make sure that I drink a lot – split it into 4-5mi section drink lots of water, and for energy is I need to First Endurance Sport drink. …and that’s it. Try to consume about 15-20oz each time I stop for hydration.
I’ll usually lose a few pounds (2-3) on a given run, even if I’m drinking at least a bit on the run (short distance, minimal heat). After I rehydrate it doesn’t take too long to get back to normal.
A few weeks ago I did a hard 14 miles on a HOT day (must have been mid 80s and humid). I didn’t drink enough and felt like crap for the last 2 miles but kept running. I weighed myself before and after (I almost always do, obsessively), it was an 8 lb loss. I weigh 150 so that was a lot. It was actually pretty dumb not to drink more, but sometimes, I’m just dumb 
Same issue here. I weight 147 lb and in bad days I’ve lost a net 7 pounds. Up to 5 lb is normal, 5-7 I feel like sh_t. Over 7 about to pass out and kidneys shut down.
5-7 I feel like sh_t. Over 7 about to pass out and kidneys shut down.
Yeah, I agree. I wonder at what point it becomes dangerous. Someone said that over enough time of doing this your body adjusts, and I suspect there is a lot of truth to that. I know I should carry water/gatorade/something! with me on longer/hotter runs, but I hate carrying shit other than GUs. I do stop when there is a fountain, most of the time, but it’s not a lot of water at each little occasional stop.
Anyone know at whay point (like % of body weight) it becomes bad for your kidneys or body in general? I should note that I drink a lot of water in general, so I feel like in an average day I’m really really well hydrated. For what that’s worth…
I’m just glad I am not the only one who sweats buckets out there.