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03/08/2011

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Ultrajumper.wordpress.com

Joel,

Great topic. With bone leaching due to an acidic diet being a prominent topic in your book Paleo Diet for Athletes, I wonder if the high amounts of gatorade, Gu, pasta, etc are giving the cyclists in these studies a greater dietary acidic load and therefore an increased risk for bone mineral leaching. The last study you reference compares cyclists to runners, so this eliminates the dietary bias and shows that the pounding of running helps strengthen bones, but I hypothesize that the bone health of cyclists is affected by both a lack of weight-bearing exercise and acidic diet. I'm curious to hear your thoughts.

Cheers,
Bobby

Don Williams

I am intrigued by how cycling has low BMD yet swimming doesn't. Is it because swimming has a better use of total body muscles then cycling and therefore lower BMD plus stronger surrounding muscles equals less fractures, I wonder?
Also I would think (unless riding only on a stationary bike) that riding on the open road would in gauge whole body muscles with the road chatter and cycling movements at least as much as a recreational person and not create a lower BMD

Rick Kiley

Joe, Many thanks for a valuable post. Most men don't know their bone density numbers. I learned mine, and that I have osteopenia, after a bike crash that fractured my pelvis.

Steve

Holy crap. I always wondered if there was anything to the theory that cycling results in weaker bones. Thanks for marshaling the science. Steve

Linda

Have any studies looked at the influence of diet on BMD? I would imagine nearly all competitive cyclists eat a high carb diet in the form of grains. Eating a lot of grains will increase the body's acid levels and in an attempt to neutralize, calcium is leached from the bones. I'm not suggesting diet is the only factor here, but I wonder whether it has been examined - e.g. have Paleo-diet followers been tested for BMD in a scientific study?

Steve

BTW, could the difference between cyclists and runners be the likelihood that cyclists sweat out more volume because of the wind rushing by?

Michael H.

Triathlon or duathlon does seem to be the best program for most amateurs, in terms of overall health benefits. Runners seem to have high injury rates but better BMD. Cyclists don't have as many overuse injuries but there's the problem with low BMD.

I would find it worrisome to focus only on road cycling without any significant amount of cross-training. Cycling carries the risk of trauma (crashes) while the training doesn't appear to build the greater BMD that could help in some crashes. I had a potentially serious crash a couple years ago when I flipped over the tri bike on a paved multiuse trail. I believe that my strength training program helped me to escape serious bone injury. I had limited range of motion in one arm for about a month because of muscle soreness but no broken bones.

Caroline

Running is used in these studies as a "weight-bearing exercise" in comparison to cycling, but is walking just as beneficial in this regard (for those who can't run and turn to cycling instead because of bad knees, for example)? Perhaps you'll get to this in your next post, but I've always wondered.

Pete Simon

Just like grandma used to say..."Everything in moderation." Things in excess seem to cause trouble sooner or later whether it be bone loss or other problems.

Steve

Joe,
I believe these studies are spot on. But what I found most disturbing was the fact that in these controlled experiments, a huge percentage of average individuals (50%) had low BMD as well! There's another variable that has not been accounted for - fluoride. We cyclists consume a lot of water, and most of it is fluoridated. We also get it from food and dental products. After doing some research on this, I was convinced. After filtering my water, I saw a dramatic difference in my joint and bone health. See a sampling of BMD+fluoride research:
http://www.fluoridealert.org/health/bone/density/cortical-trabecular.html

Just hoping I can help another brother out. Love the blog!

Andrew

Thought you might be interested in this article by Dr. Gabe Mirkin, "Cycling Does Not Cause Bone Loss."
http://www.drmirkin.com/public/ezine091210.html

Will

Great post and a subject dear (unfortunately) to my heart. I am a cyclist with osteopenia diagnosed after I fractured my femoral neck. i have not been treated with bisphosphonates (very uncomfortable wth this protocol) but have since suffered another 2 fractures; 1 on bike and 1 not. Before turning to bisphosphonates, I am working on dietary changes. I am very curious to know what your readers do for bone care besides weight bearing exercise.

Bad knees and feet mean i can't run. I try to hike and do moderate resistance training and just stay as un-sedentary as possible. On the diet side, I avoid animal proteins and high sugar foods. I don't think caffeine is quite the BMD evil people make it out to be but I drink in moderation. I try to get adequate dietary calcium (prunes!) with attention to oxalates, fiber, and other nutrients that interfere with calcium absorption. While not keen on using supplements, I feel a need to be aggressive because of my bad bones. I take 1,000mg Vit D daily unless I've been out in the sun quite a lot, along with a calcium supplement.

I've read that some soy sources are tremendously helpful for bone protection. Also, another tip is that the body can't absorb more than >500mg calcium supplement at a shot, so it's best to divide up the dosage during the day (I find that a liquid calcium supplement is far easier to get down). Lastly, some research has shown that replacing calcium during sweaty exercise may be vastly more beneficial than chowing it down afterwards. I don't think there are many exercise drinks containing calcium but maybe we'll see more in the future.

I will stay tuned to see what others have to add to this important topic. And please, folks (especially men who think osteopenia/pororis is the "old lady's disease"!), get a baseline BMD now and keep an eye on it before it's too late. It is possible to improve on low bone density to a degree but far more prudent to take steps now to protect it, especially because of the high risk of crashing that comes with cycling.

Thanks, Joe!

Mark @ SPDShoes.org

Crumbs - I had a fall in July and broke the neck of my femur (details here if you REALLY want to know! http://www.spdshoes.org/spd-shoes-broke-my-leg/ ).

Aside from the fact that this is probably going to keep me out of any serious MTB action for the next year (the risk of reinjury and further complications makes caution the best policy), I have also had a number of people say to me, well how come your femur broke that easily? Are you sure your bone density is not down or something? I kinda dismissed that, I mean it was a pretty hard, flat fall on the hip. But I just came across your article and it's made me think... My surgeon certainly never looked into the matter, but perhaps I had better get a bone scan and take it to him at the next appointment for peace of mind...

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