Calcium loss through sweat

[Ann G]

Hi, I just registered here. I've been an avid cyclist for the last 4 years, and went on RAGBRAI all of those years. I've been aware that cyclists and swimmers have the worst bone density for awhile, but I managed to lie to myself about that until recently. (I told myself that the problem was restricting exercize to cycling, and not engaging in strength training and weight bearing exercize.) From what I've read lately, it's really the cycling itself. The problem is that you lose calcium through sweat while engaging in exercize that is not a weight bearing exercize. The calcium leaches right out of the bones. I'm already on meds (evista) for low bone density, even though I walk (every day during fall, winter, and spring, but I'll admit, less often during the summer) and use weight machines at the Y (usually twice a week). I've considered quitting cycling because of the bone density issue, but lately I've been reading about some sports drinks that contain calcium (along with other electrolytes lost through sweat). Up until now I've just put water in the bottles on the bike, and try to have at least 2 servings of dairy products per day. Okay, I should probably increase it to 3 per day, but that doesn't solve the problem of what to put in the water bottles. Right now I'm looking at some products that contain calcium in with the mix, like Ultima Replenisher. One thing I like about it is that it's available in single-serving packets, so would be easier to deal with on a bike. Is anybody else concerned about this issue, and have you come up with a solution?

[Aint Doody]

That's really interesting. I'd be interested to know all the sports drinks containing calcium. I have a friend (male) who sweats profusely and loads up on Tums before he rides to prevent muscle cramps. I never thought about bone loss.

[Ann G]

Here is a site that has a chart with several different sports drinks and various ingredients that they contain. I didn't see Propel on here, but there is a Propel Calcium Fitness water too.

http://www.eload.net/eProductChart1.htm

[sarahlou]

All of our bodies minerals are lost through sweat (and urine) so you need to keep up on minerals daily. And in order to absorb calcium, you need vitamin D- the two go hand in hand. So if you're worried about calcium, also look at vitamin D intake.

[mimitabby]

I found this from 1950:

Perspiration as a Factor Influencing the Requirement for Calcium and Iron
Frances A. Johnston, Thelma J. McMillan and Erica R. Evans

The College of Home Economics and the School of Nutrition, Cornell University, Ithaca, New York

Perspiration was collected from 4 young women, each of whom served as a subject for 4 periods of approximately an hour each. The temperatures used were 97°F. dry bulb and 93°F. wet bulb. The collection was made in enamel tubs in which the subjects sat during the sweating period. Perspiration from all parts of the body except the scalp was collected.

The mean loss of body-weight per hour during the collection periods was 10.87 ounces (308 gm). The mean loss of iron per kilogram of body-weight loss for each of the 4 subjects was 0.24, 0.26, 0.26, and 0.28 mg; the mean loss per hour was 0.48, 0.063, 0.080 and 0.108 mg. The mean loss of calcium per kilogram of body-weight loss for each of the 4 subjects was 13.42, 30.42, 32.52 and 40.10 mg; the mean loss per hour was 4.17, 6.80, 8.84 and 14.33 mg.

The administration of 25 mg of iron with breakfast on the day of the collection did not increase the loss of iron, nor did a subject who was taking iron therapy daily secrete more iron than the other subjects.


okay, they were losing almost 11 ounces of body weight AN HOUR and losing about 30 milligrams of calcium an hour.
If you are taking your 1000 mg of Calcium a day; you are COVERED. and ALL exercise will do this to you, but since Bicycling doesn't "weight bear" it doesn't rebuild what you lose

[Ann G]

1250 mg, but I'm still on evista for low bone density. I've been seriously considering quitting cycling, but since it's my favorite form of exercise, I'm looking for alternatives. It would be nice to think that since I'm taking extra calcium I don't need to worry about this, but somehow I don't think it's working that way.

[mimitabby]

Ann, I am in the same boat as you. I started doing weigh bearing exercises as well for Osteo. I do 10 minutes of stairs 4-5 times a week, I walk a mile a day; if you can run that's even better. I also am lifting weights under the guidance of a trainer with bone building in mind.
I believe that if it wasn't for bicycling, i would never have the strength or stick to it iveness to do any of this stuff, so don't give up cycling, just augment it.

[silver]

1250 mg, but I'm still on evista for low bone density. I've been seriously considering quitting cycling, but since it's my favorite form of exercise, I'm looking for alternatives. It would be nice to think that since I'm taking extra calcium I don't need to worry about this, but somehow I don't think it's working that way.

Cycling is my favorite! I got into exercise running, then broke both my feet one at a time, so I got a bike.

So, the answer is TRIATHLON!!!! You get to ride, and you are forced to run and swim (or that's how I look at it) and it's fun! Give it a thought!

[Thorn]

Yep...I think there is something healthy to the triathlon suggestion. After my DH read an article that said that an otherwise healthy young female cyclist was tested with a bone density of an 60 year old, I started to question my cycling, too.

Prior to finding bicycling again, we did a lot of walking and hiking. But, walking isn't aerobic enough anymore. Also, DH (he is a voracious reader) found an article that claimed walking by itself may not be enough--it is the stress of and variety of the exercise that builds bone mass. This is the same reason they say to peroidically change your weight routines if you're trying for bone density. Some articles were recommending weight vests for walking to increase the stress.

For me, besides putting more calcium in my diet, I've realized I guess I have to put some running into my routine. I don't want to give up riding (I so prefer it) so I'm planning on adding a "brick" as the triathlon gals call it to shorter rides. That is, after i come back, adding a short, 1 mile run. One mile seems to be a minimum that is often suggested, but I remember what those runs after rides felt like--uuufff....that should be a stress.

If anyone has some good solid references/recommendations on this, I'd love to read them. It seems like the issue of hormone replacement therapy that we are the generation that will be experimented on.