Hi all, first post here, looking for some guidance since I've been finding conflicting info on the web. Basically I'm worried that I might be approaching dangerous weight loss levels during training/racing and I'm looking for feedback on a) what is truly a safe % weight loss and b) how people who sweat excessively &/or have a hard time ingesting fluids compensate.
For some background information, I'm a 5'9" male, ~165lbs, 31 yrs. I train less than 10 hours a week and have completed about 9 triathlons (sprint & oly) and have my first HIM next month (Montauk MightyMan). As I've been training this summer my observation of my weight loss during sessions has progressed from, "wow, its crazy that I sweat that much!" to "hmm, this might be dangerous". As an example, last night I did a brick workout; 60mi bike followed by a 10mi run, in relatively cool weather. Before I left the house I was about 169lbs, by the time I got home I was around 159lbs. That's just about 6% (10lb) body weight loss in a little over 5 hours, and I wasn't "going hard". This is fairly typical for me- I can easily lose 6-8lbs in shorter 2-3 hour runs because I have a tendency to sweat way more than other people in all conditions, and especially when exercising.
My concern comes from the following chart I came across on the hammer nutrition website while googling weight loss %:
Symptoms by percent body weight water loss:
[Nutrition for Cyclists, Grandjean & Ruud, Clinics in Sports Med. Vol 13(1);235-246. Jan 1994]
So typically I'm in the range of 4-6% weight loss when I exercise for over 2 hours and I know I cold easily exceed that over the course of a HIM at an elevated race pace. This chart doesn't say what happens at 8% or 9% loss, but you can easily guess that it isn't good.
In terms of conflicting information, I came across this chart on an ultra-running website:
Up to five percent weight loss. This is an appropriate weight loss, and the runner should be allowed to continue unless there are signs of distress.
Five – seven percent weight loss. The runner should be encouraged to increase fluid and salt intake and allowed to continue unless there are signs of distress.
Seven percent or greater weight loss. If mental status is satisfactory, the runner should be advised to increase fluid and salt intake. If vomiting or the inability to rehydrate is evident, the runner should attempt to recuperate until rehydration is possible before continuing.
It seems to make a much smaller deal about weight loss levels that the first chart indicates are dangerous. So, what do folks find their weight loss % to typically be? What are your hydration techniques? I know it is not possible to replace anything approaching fluid loss in races, but I find it extremely difficult to drink even recommended amounts. Last week I did a 20mi run and probably drank about 24oz, and that was pushing it.
Again, thanks for the feedback,
Kevin
For some background information, I'm a 5'9" male, ~165lbs, 31 yrs. I train less than 10 hours a week and have completed about 9 triathlons (sprint & oly) and have my first HIM next month (Montauk MightyMan). As I've been training this summer my observation of my weight loss during sessions has progressed from, "wow, its crazy that I sweat that much!" to "hmm, this might be dangerous". As an example, last night I did a brick workout; 60mi bike followed by a 10mi run, in relatively cool weather. Before I left the house I was about 169lbs, by the time I got home I was around 159lbs. That's just about 6% (10lb) body weight loss in a little over 5 hours, and I wasn't "going hard". This is fairly typical for me- I can easily lose 6-8lbs in shorter 2-3 hour runs because I have a tendency to sweat way more than other people in all conditions, and especially when exercising.
My concern comes from the following chart I came across on the hammer nutrition website while googling weight loss %:
Symptoms by percent body weight water loss:
- PERCENT WATER LOST --------- SYMPTOMS
- 0% --- none, optimal performance, normal heat regulation
- 1% --- thirst stimulated, heat regulation during exercise altered, performance declines
- 2% --- further decrease in heat regulation, hinders performance, increased thirst
- 3% --- more of the same (worsening performance)
- 4% --- exercise performance cut by 20 - 30%
- 5% --- headache, irritability, "spaced-out" feeling, fatigue
- 6% --- weakness, severe loss of thermoregulation
- 7% --- collapse likely unless exercise stops
- 10% -- comatose
- 11% -- death likely
[Nutrition for Cyclists, Grandjean & Ruud, Clinics in Sports Med. Vol 13(1);235-246. Jan 1994]
So typically I'm in the range of 4-6% weight loss when I exercise for over 2 hours and I know I cold easily exceed that over the course of a HIM at an elevated race pace. This chart doesn't say what happens at 8% or 9% loss, but you can easily guess that it isn't good.
In terms of conflicting information, I came across this chart on an ultra-running website:
Up to five percent weight loss. This is an appropriate weight loss, and the runner should be allowed to continue unless there are signs of distress.
Five – seven percent weight loss. The runner should be encouraged to increase fluid and salt intake and allowed to continue unless there are signs of distress.
Seven percent or greater weight loss. If mental status is satisfactory, the runner should be advised to increase fluid and salt intake. If vomiting or the inability to rehydrate is evident, the runner should attempt to recuperate until rehydration is possible before continuing.
It seems to make a much smaller deal about weight loss levels that the first chart indicates are dangerous. So, what do folks find their weight loss % to typically be? What are your hydration techniques? I know it is not possible to replace anything approaching fluid loss in races, but I find it extremely difficult to drink even recommended amounts. Last week I did a 20mi run and probably drank about 24oz, and that was pushing it.
Again, thanks for the feedback,
Kevin