I did my biggest run of the season so far yesterday - 90mins, roughly 16/17ks. I lost a total of 2.2kgs of fluid during this run. I left weighing 95 kgs, took in 540gms of fluid after an hour, pee’d out 260gms, and weighed in at a touch over 93kgs on my return.
Is this a lot to lose? I am quite big, and sweat heavily especially in the heat, and I have had cramping issues in the past. My solution this season is, for longer events, to use electrolyte caps.
So, how much do you all sweat? Am I right to guess that it is hard to make up this sort of gap with fluids only, and that taking in heaps of fluids could lead to gastro problems? What does the vastly experienced slowtwitch crew do?
ok the first logical question has to be … how the hell do you know you urinated 260gms??? Scratch that I don’t think we want to know. Just don’t keep it under your bed!
From what I’ve been told it’s extremely hard to maintain weight of fluid and I don’t believe anyone even tries to. Sounds though that you are taking in way too little fluids. Should be aiming for 750ml of sports drink and 250ml of water to go with your edible carbs/gels etc. Even more so considering your weight. I’m only 77-78 kg and that’s what I’ve been advised to ingest.
I’ve sweat almost 10 lbs on some runs without stopping for water. They key is to keep your fluid levels in your body high by drinking all day long and then after the run. As long as you arent dizzy when you’re running, don’t worry about it.
Yeah, I feel find during the stand alone runs, it is the back end of a half running which concerns me. I need a solid nutrition plan for those longer race days, and I am just experimenting at the moment.
So any hints/tips/suggestions will be gratefully absorbed.
In warm conditions I sweat as much as 1.5 quarts per hour. In the pool, if it is hot, I can lose 2.5 pounds in one hour if I am not drinking water(which is one of the reasons I started bringing my water bottle poolside).
For longer events(2+ hours) you should definitely be using some kind of salt replacement, simply because you are sweating out a lot, and most of the fluid replacements available at races do not contain nearly as much sodium/potassium as you are losing through sweat.
I will usually take one Lava Salt every 30 minutes on rides, runs, or races that I expect to go over two hours.
As someone else pointed out, I don’t want to know how you know how much you urinated, but I now have a terrible vision in my brain that involves an Erylemeyer flask and a guy at the side of the road in a lab coat.
Well, to put people’s minds at rest, I held it in until my aid station (home) at the one hour mark, and I had an old sprite bottle ready for the purpose. I weighed it at the end of the run. I bet heaps of people have done the same…Bueller? Bueller? Anyone?..
Measured up to 1.5L/hr when training heavy in hot humid weather. Higher at race pace. Range in training has been anywhere from 500ml/hr to the 1.5 L/hr.
You don’t have to “collect” to measure. Just weigh naked prior to the run and afterwards. Add to the total fluids consumed (16 oz/lb). Divide by time.
I’ve heard that performance begins to deteriorate after approximately 2% fluid loss (2% of body weight, that is). For a 90 minute run, your numbers don’t look so bad.
I’m on the wrong side of 90kg myself. A typical 2 hour run (say, 1/2 marathon) will see me lose about 3kg even with drinking 750ml per hour. But, on a training run I like to drink even more - and that takes practice! Anyway, shoot for 1 to 2 bottles of fluids per hour for every workout over an hour. Weigh yourself before and after each workout just to make sure that you are consuming the right amounts.
Wow. I apparently sweat more than most people first of all. And I also dont drink during runs unless i’m doing intervals or it’s more than 13 miles. Maybe i should change that some time.
I’ve heard that performance begins to deteriorate after approximately 2% fluid loss (2% of body weight, that is).
Very true. I didn’t for a long time, but have recently started weighing myself naked before and after each run, and checking still clothed in the middle of a run if it happens to go back past my house (which is usually the case in runs over 10 miles).
On biking, I check every 50 miles to make sure. On the bike in the sauna of summer here in Floriduh I can easily sweat 30-40oz an hour, and it’s easy to become very dehydrated. At 70kg it’s a lot worse for me than others, but I cen definitely tell a big difference in performance if I drop 5lb (about 3%).
I drink about every 3-3.5 miles on my training runs, and can easily drop 3-4lb in 7 miles under extreme conditions and poor hydration. I try to keep my weight drop to less than 2lb over any distance, and if I drop too much I’ll pause my run to rehydrate for a half hour.
On the bike I “try” to consume 2 bottles per hour. But, if it’s hot I try to get to three! At IM Moo '03, I drank 18 bottles of Gatorade, 2 bottles of water (with salt tablets) and 1.5L of concentrated R4 and still came into T2 dehydrated.
My body seems to seek 2 lbs per hour in most circumstances. So, easy math 1 bottle = 1 lbs. I just can’t drink more than 3 bottles an hour. It’s just too hard to process.
Anyway, there’s discussion nowadays that you want to keep up with hydration on the bike and then allow yourself to dehydrate a little for the run. I simply drink less on the run (during a race) in order to let my stomach clear. It’s hard enough hauling this mass around without all the sloshing.
no one seems to have noted that the first 2kg or so of fluid loss does not result in any dehydration at all. glycogen is stored in the muscle together with water. as you burn off the fuel load, you also release the water.