What do I do with it???
Sweat Rate (ounces/hr) 34
Sweat Sodium Loss (milligrams/hour) 724
Drink 34 oz/hr when training and racing? Is this how much salt I need to consume an hour?? Is that a lot?
I’m no help, except to say that you don’t have to replace every last ounce of your water loss – losing one or two percent of your bodyweight is no problem.
But how’d you figure out your rate of sodium loss? I’d be very interested to determine my own.
You are using ounces per hour and milligrams/hour.
First using the metric system and be consistent with your units of measurment.
How do you know that the conditions on race day will be similar? It might be warmer or colder. Do you know the rate in which you can digest and absorb?
Had it done here in Austin with TriHarder Multisports.
Cool, thanks.
So what did the test involve? I understand how to weigh myself before & after exercise. But how did they test the salinity of your sweat?
cray,
Thanks for sharing that and allowing some of us to learn more about this issue.
Just like sjstuart, I’m interested to know how they measured how much sodium was lost. It is an issue for me as well. I perspire profusely, especially when it is hot and or humid, and replacing enough sodium becomes an issue for me.
Also, isn’t the amount of perspiration excreted dependent upon the exertion level? Then add heat and humidity to that equation as well. For example, if its hot and humid and you are exerting yourself at a very high level, say LT, your body will be working extremely hard at trying to cool itself (sweating). The high humidity will slow the evaporation process and reduce the cooling effect on your body. Then your body will sweat more to try to make up for this reduced cooling effect it is subjected to.
If it is cooler and drier, your body will not have to work as hard to cool itself even though you are working just as hard. Because the humidity is lower and the temperature is cooler, you will not have to sweat as much to keep cool. Your perspiration will evaporate much easily and faster and this will have a greater cooling effect on your body.
It was cool. Matt did a study on Kona participants in the past couple of years also. I found it on the internet when I did a search on his name.
They measured the salinity in a lab. Sorry, guess that’s not real doable from home.
7 min warm-up on the bike on a Computrainer then they sent me into the restroom to strip, dry off, and weigh myself. Then they put a cloth patch on my shoulder and another on my forearm. I rode for 30 min at 65-70% HR, not sure what wattage, I didn’t think to ask. They also gave me some water, not sure how much but told me to drink all of it during the workout. When I was done, they peeled the patches off, I dried off and weighed myself again. It’s official now - I don’t sweat. 
Cam
Also, isn’t the amount of perspiration excreted dependent upon the exertion level? Then add heat and humidity to that equation as well.
Hi Ben, I’m sure it is. This is Texas so it’s hot and humid about 75% of the year.
I was hoping the Slowtwitch gods could help me figure out how to apply the info.
Cam
All it really tells you is at the same rate of exertion, temperature, humidity, etc. as the lab test was done you sweated 34 ounces / hour. A single number is useless to estimate sweat rate under different conditions.
If your sodium loss is consistent, one thing it does show is with a product like Gatorade which has 418 mg of sodium in a 32 oz serving you would only be replacing about 2/3 of your sodium loss so would need to supplement the sodium.
Ask the people who did the test what to do with the numbers
Quote: "I was hoping the Slowtwitch gods could help me figure out how to apply the info.
"
Cam,
You and me both.