Bone catabolism during exercise
 

Another fantastic episode of Inside Exercise. As is so often the case, everything I know is wrong.

Wasn’t it already known that non-weight bearing cardio weakens bones, but weight-bearing exercise strengthens them? (Or at least slows bone loss)

Yes, but she has looked into the mechanism and it’s fascinating, at least to me as a physiology nerd. I also like that pod because the guests tend to be real scientists who embrace complexity and don’t make categorical statements when they don’t have the goods.

Thanks for this! I’ve started listening to this series on Spotify. Following this great discussion on the effects of exercise on bone health have been good segments on resistance training, effect of heat when exercising and several others. 👍

Otto

Bone catabolism just like muscle catabolism only applies to cyclists who fail to cross train by lifting weights and do other forms of resistance training and who follow poor nutrition.

I've been a gym member since '79 and a distance rider since '95. I have osteoporosis, have been treated for it for 5 years with little progress because I'm also cycling. I'm not the only one. When was your last DEXA scan? I had no idea. Never had a fracture and I fall all the time (skiing) and have been on the floor a couple times recently from a syncope. Maybe I'm good at falling.

The Pope is infallible. Must be the seed oils, or maybe your politics.

BTW, my own earlier pronouncements on bone were naive, given what Prof. Kohrt had to say. I will probably end up paying cash for a DEXA if I can't get my PCP to justify it.

high impact sports signals the brain to tell the body to produce something that maintains bone density, correct? That is why at age 59 I'm trying desperately to not have to give up jogging. My knees want me to quit jogging though.

Insurance would not cover my first DEXA scan but it was inexpensive out of pocket, under $100 IIRC. My hip T Score was in the -2.5 to -3.0 range and back was in the -2.0 to -2.5 range. Both reversed to zero or better in about 18 months. The good news? Insurance paid for the second scan. :)

Another reason to eliminate exercise. Too complicated. <snicker>

I had more than one DEXA because I had PMR, twice. Weird. I was treated with a few months of prednisone.

Was it at a sports lab or a clinical facility?

Legit.

This might interest you. I've read two studies which showed, or seemed to show (I'm a naif), that taking 1g of calcium before exercise prevented that drop in serum calcium. Whether or not that fixed the problem is another question. Anyway, I tried that for a couple years. In the succeeding year just gone by, I've had 3 stents, so there's that, too, and I've quit the pre-exercise calcium just in case. My cardiologists have no opinion, but they're mechanics, not researchers. I tried to get an appointment with a cardiologist at a university, but guess what, they teach and do research and had no time for an appointment.

I'm not quite ready to go there, since the drop in Ca hasn't been conclusively linked to bone loss. I'm also concerned about kidney stones.

The vessel thing is interesting for sure. As I'm sure you know, there's some optimistic speculation that the mineralization or athletes coronaries is "benign" and maybe not associated with plaque. When I had my c-spine surgery back in 2008, they found calcium in one of my carotids on CT. I had a doppler echo study at the time and they said it was wide open. We're all on borrowed time.

I had a calcium scan in '17 which showed calcium deposits and like you say, i pretty much ignored the finding because . . . Until I had an angiogram in January which the cardio said was unnecessary, except he put in 2 stents, circumflex 90% blocked, and 75% in the LAD. Then I had a minor heart attack, different artery and another stent. So not benign in my case. OTOH, I was that blocked and didn't die, so there's that. Maybe cycling is just fine. There's also the weird idea that all that calcium came out of my bones and wound up in my heart . . .

I’m 60 and started running again about a year ago. I don’t exactly jog though. I run in relatively minimal shoes (thin, flexible, wide, no support and only slight cushion), and use a technique that includes: 1) forward leaning posture, 2) high cadence (165 bpm at 10 minute pace and moving up to 180 bpm for 8 minute or faster), 3) compact arm movement and 4) knees bent at impact. I use forefoot strike though a mid foot strike can work this way, too.

My knees don’t complain much but it definitely revs my heart so it typically counts as a hard workout, either threshold or intervals. Actually, i have lately been alternating mostly running with a short bit of walking to give my feet a chance to recover from the work.

Anyway, if that technique isn’t familiar to you, you may wish to investigate it. It has allowed me to get back into running without hurting my knees. I have an indoor track available all year, so I run very regularly in winter cold and summer heat.

Otto

Thanks, I added that podcast and episode to my jogging/walking playlist.

On bike rides I just listen to ambient sounds and my bones cracking.