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MOTIVATED@LAST Posts: 15,443
3/5/13 7:03 A

Actually, it's not that silly.

Weighing people before, during and after a race is common in ultramarathons (ie. greater than 26 miles) and other endurance events, as a means of tracking their hydration levels.

(Too much water is potentially as dangerous as too little).


JANEY102482 Posts: 393
3/4/13 9:42 A

Thanks for the explanation, everyone. I should have clarified that I was weighing myself before and after the race because I was curious to see what the fluctuation (if any) would be like. Kind of like a science experiment! Like I said, I almost never get that much exercise in a day, so I wanted to see what would happen weight-wise. Now I know!

MOTIVATED@LAST Posts: 15,443
3/4/13 6:42 A

Just to put things in context, a pound of fat represents around 3500 calories.

Running burns around 140-150 calories per mile, so maybe you burned 700-750 calories. 3 ounces is probably less than the margin of error in your scale anyway.

And I am assuming that you didn't eat an extra 6500 calories afterwards.

Day to day shifts in the scale are almost always water weight. And yes it is a very common response to increasing an exercise program for your muscles to retain water.

As for "didn't sweat much", this is a very subjective measure. In low humidity conditions, with a bit of wind about (or creating your own wind through running), it is possible to stay cool, sweat quite a bit, but for the rate of evaporation to pretty much equal the rate at which you are sweating, so not really experience a noticeable buildup of sweat. 1.5 lbs of sweat loss in 5 miles seems quite feasible.


ELLESSE0 SparkPoints: (8,241)
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3/3/13 4:08 P

I wouldn't stress about little fluctuations in the scale over such short time periods. I used to obsessively weigh myself, and now it's not totally uncommon for me to go a week or longer without weighing myself. Also, I always try to do it first thing in the morning to stay consistent.

If you're trying to lose weight and the scale isn't budging or heading the other direction over a couple weeks, then I'd try to assess what in your diet or exercise plan might need tweaking. But one race isn't going to have a long term effect on your weight one way or the other.

Awesome for getting out there and doing it, by the way! Good luck!

UNIDENT Posts: 33,498
3/3/13 1:21 P

Significantly increasing exercise will cause water retention, yes.

Why are you weighing yourself before a race, after the race, and the next morning?

Stick to once-a-day at most, at the same time of day in the same conditions.

You'll have eaten and drank since your race too, so the 1.8lbs might be a reflection of how much food/drink weight is simply yet to be converted to energy as well.

Weigh yourself now. Go drink a double glass of water. Weigh yourself again. You just "gained" half a pound.

3/3/13 12:18 P

Just guessing, but it seems like maybe the extra exertion caused you to retain some water. When you step on the scale that often, the fluctuations don't say anything about your actual weight. I am pretty scale obsessed, can't walk past a scale without stepping on it. I've seen my weight change by 2 pounds in 10 minutes. It is impossible to gain or lose that much fat in that amount of time. It just shows that the water in my body has shifted around some.

JANEY102482 Posts: 393
3/3/13 8:54 A

I ran a 5-mile race yesterday. Before I ran I was 140, and after the race I was 138.4 I didn't sweat much, plus 138.6 was my weight one week ago, so I thought that was right. Today, however, I'm 140.4. Is this a result of the exercise I did yesterday? I don't normally get anywhere near that much exercise, so I don't know what to expect.

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