I had a DEXA scan recently and was shocked to see I was in the lowest 4% for bone density in my 35-44 male population set.
I’m not a small guy:
-79 kg (178lbs)
-6ft tall
-10% body fat
So I have a fair amount of muscle on my build so I don’t fit the typical frail cycling archetype.
I lifted weights and did sport/fitness activities for over 20 years and did a lot of running (ironman, marathons, etc) up until about five years ago when I had the first of my four children and shifted to mostly cycling and one weekly yoga/core session given the time limitations. I probably run once a month on average now outside of chasing the kids around
But after seeing such a low bone density score I’m wondering if that could actually be a result of the greater focus on cycling or if it’s mostly genetics and I’ve probably always been low.
Anybody have any links to studies on this? I’m wondering if I should actually do something about this and incorporate specific strength training exercise and running into my schedule or if I can just chalk it up to genetics in that any shift would likely only bring very marginal gains- which at this point I don’t have much time for. Thanks!
Did they measure actual density or did you get bone mass as a % of lean body weight. If you scored a very low % of bone mass compared to total body weight the cause seems obvious when you have so much muscle that takes up a large % of your lean weight and so less is available for bone but if they actually measured density than of course that’s a whole other story
If you look up studies, you’ll find runners as well with low bone density. I think the theories are chronic calorie deficits, reds, and chronic low* testosterone for men.
I will respond to this more in depth later. In the interim, the values you need to report are your Z-scores at total hip (TH), femoral neck (FN), and lumbar spine (LS, sometimes also called PA spine).
If you have low bone density, I highly doubt it because you cycle in your bike for under 10hours per week. I’m pretty sure the pros who do 25-35hours per week get it and this idea has been blown out of proportion.
Think about the average person who works at a desk and then comes home to sit on their couch to watch tv and then make it over to their bed to sleep and do it again the next day. Why would they have higher bone density than any of us recreationally riding bikes for exercise.
Lifting weights could help you increase bone density, but I doubt you’re at risk of osteoporosis anyways
Thanks, interesting. I did a Testosterone test 10 years ago and was on the lower end but again 6 years ago and was normal. Maybe I should test again.
I’m curious on if it is a dependable biomarker or if I should just ignore.
I definitely am not at a calorie deficit (I don’t restrict anything and have been within 3% of my base weight for last 10 years) and I don’t have reds.
I have worked out pretty intensely for years but certainly not overdoing it in my opinion. Maybe 1-2 Vo2 max workouts at most during a week and sometimes not for a few months. 4-6 hours of exercise per week.
Vo2 max was tested at 78 last summer so have good fitness and good overall health biomarkers.
The one thing is I have not been a beacon of calm and low stress in recent years. 4 kids under 6 yrs of age compromised sleep and getting sick more often, and with a stressful job. Which is why I’m curious if any of those components could influence bone density. Or if there isn’t any research, I’ll just start taking a multivitamin and be done with it!
@The_Conductor - z-score of -.5 - data below if that’s what you’re referring to.
If your vo2max is 78, that is world class (world tour level). Yet you only train 4-6 hours of exercise per week. That seems highly unlikely. You sure that’s right?
It was lab tested. Also did a lactate threshold a month later and an experienced technician told me it was at 395 watts. Although prob was closer to 380.
But that was after a couple months of the most consistent training I’d done since covid. So probably more like 6-8 hours per week for prior 2 months.
It’s a good question though. I believe is a lot down to training hard for the last 25 years of my life and rarely going a month without pushing myself. But I’m sure genetics play a role as well but I have no athletes in my family, just grandparents who were farmers!
Athletes with reds can be weight stable as well. You may be in an overall calorie balance but it’s those constant hard workouts that take days to recover from. It’s like half your life you are in a deficit and the other half energy positive. They may balance out over the week/month but you still existed half your life in a catabolic state.
I’m not saying that this is you but just what could possibly be.
If my scales are to be believed Bone Mass (LB) 7.4 whatever that means if its bone lbs, its 5.4% which according to their scale is perfect. Below 3.6% is what its classing as low and by that your healthy @DadGoals
This link and others suggest that -.5 isn’t that bad. It’s low but less than -2.5 is troublesome and it’s used to diagnose secondary osteoporosis.
You may want to run your numbers by a doctor in the future.
Summary
Doctors use Z-scores to diagnose osteoporosis in children, teenagers, premenopausal females, and younger males. A score of -2.5 or lessTrusted Source suggests that a person may have secondary osteoporosis, which does not result from aging.
I’m being monitored for low BMD after my new family doctor was looking into reason for chronic neck pain. Had a spine X-ray which led to the question of when did you break your back? Eh what? Turns out I have the remnants of cracked vertebrae (T6/7) which in turn led to scans for BMD and referral to endocrinologist, who was ready to start me on meds for it as I was border line for age & gender. Fortunately a blood test came back normal so for now, it’s calcium and D3 supplements and monitor.
As for cycling, well even though I spent several off seasons lifting, it’s mostly been, desk job, cycling, couch. Cause, correlation, coincidence, who knows???
Disclaimer: I am a doctor, but not your doctor. I have been a researcher in this field for the better part of a decade so…take that for what it’s worth.
First, it seems like your DXA is a consumer DXA? Especially since it specifically says “this is not a bone density report.” Regardless, the reported Z-score at the total body (TB) is useless. The TB is not a site that we measure in adults when evaluating bone health. Even if it were, a Z-score of -0.5 is well within the normal range and is nothing to worry about. We start getting worried when the Z-score is below -2 (ISCD guidelines). Of course, athletes are not all-comers and should have higher BMD than your average person—for weight bearing athletes, we typically get worried when scores are below -1 (we can have a spirited debate about whether or not cycling is a weight-bearing activity…suffice to say it isn’t as weightless as swimming but definitely not as osteogenic as running).
I’ll cut to the chase and just say ignore it. It isn’t dependable. There is no one biomarker. It’s about the picture. Furthermore, a test on the “lower end” is still normal. More is not more. And unless the sample was taken at ~8am (preferably fasted), it can’t really be interpreted.
Furthermore, chronically trained male endurance athletes have been shown to have low testosterone levels without any deleterious effects on health or performance (exercise-associated hypogonadal male condition; Anthony Hackney at UNC is the pioneer).
I’m not saying you do or you don’t, but saying it doesn’t make it so. There are studies in which athletes with REDs weigh more than those without. This is not entirely surprising if you look at the components of calculating energy availability: the denominator is lean body mass (a surrogate for metabolically active tissue). Muscle is more dense than adipose etc etc etc and you can see how this happens.
To the topic’s question, even though we’ve shown that it isn’t relevant to the specifics: do all cyclists have low BMD? Emphatically not. Overall, the studies are somewhat mixed. At a quick glance, a recurring them is that pros have worse BMD than amateurs. I’d say it’s the behaviors associated with cycling, not the act of cycling itself, that puts people at risk for poor bone health.
I am not a doctor, and may well risk looking foolish by chiming in after one, but my understanding was that it was theorised that many of the low bone density findings in pro cyclists were explained by very prolonged periods at an unusually low body weight and/or calorie deficit.
Basically, yeah. That’s what I mean about “behaviors associated with [pro] cycling.” There’s also the day-to-day stuff normal people do that is osteogenic, eg, I bet Vingegaard isn’t wondering when he should screen the soil in his garden this spring the way that I am (if you’re standing, you can be sitting, if you’re sitting…).
Side note: pro cyclists are a darn challenging group to study. On the one hand, it’s one of the few sports that we can collect really good data. On the other hand, lord knows what pharmaceuticals they’re on that’s messing up their physiology. I had a review once ask me to cite several papers from the 1998 Vuelta in my manuscript. My response was that 7 of the top 10 were caught doping, and 2 of those who weren’t beat Lance, so you tell me what they were doing.
Thank you, very helpful. This was a mass market DEXA scan. Was just curious on body composition and saw this which piqued my interest.
Appreciate the insight and guidance! I need a doctor that is focused on athletics. Anybody have guidance on how to find them? I’d imagine word of mouth or just googling? I’m in Marin County, CA. I looked a few months ago and couldn’t find anything notable online.
