When does dehydration from a workout become dangerous? The short answer is when the weight lost by sweating exceeds three percent of your body weight. Dehydration caused by sweating can, according to this piece in the Scientific American, lead to "suboptimal performance," and in extreme cases lightheadedness and loss of consciousness, which can really lead to suboptimal performance. Sciam reports that to estimate for the amount of moisture lost, trainers subtract a player's postgame weight from his pregame weight. The difference is approximately how much fluid they have lostâ€â€and not yet replaced. The max they can lose? Most trainers keep it below three percent.
Health, fitness and lifestyle tips for people over 50 who still like to play hard
Saturday, May 31, 2025
I would say that by the time your body tells you your thirsty, your dehydrated. Which is a little past the time to drink. One thing in this article I totally agree with is lightheadedness and loss of consciousness is definately going to lead to suboptimal performance. lol
I am 70 year old. I work out 3-4 days a week. Sweat a lot. I experience lightheadedness many days. Is it possible that dehydration could be the problem. I drink 2-3 glasses of water a day
For Jim. That 2-3 glasses isn’t very much water.
By the time you feel thirsty, you have already lost about 2% of your body weight. The problem is not just fluid loss, but change in the balance of your electrolytes. The air temp where you are exercising can also be a factor. See:
http://www.youtube.com/watch?v=86TujPr1BT4
Gordon is correct that 2-3 glasses may not be sufficient on days Jim works out, especially if his workouts start to approach 1 hr.
Boy Jim, I agree with Gordon. For one who works out, and sweats alot, that does not sound like it is enough water at all. Assuming the glasses are say 8-12 oz. That lightheadedness may be dehydration, or you may be a little too strenuous on yourself. Good question…
As the Navy corpsmen tell the Marines: “if you’re peeing yellow drink another water fellow”; “if you’re peeing white you’re all right”. White meaning essentially clear to light in color.
Agreed. I remember a similar comment from some doctor on somebody’s talk show who said to “Pee pale”. Although it is tougher during winter to drink enough water. It chills me so I end up not drinking enough. But during dinner I will always drink at least 2 glasses (about 16oz per glass) with my dinner.
i remember i drunk more water more than 8 glass. i feel good of my body.