A longitudinal study found that 84.2% of master cyclists were osteopenic or osteoporotic.
You can ride a century, hold a solid FTP, and have the cardiovascular engine of someone half your age, yet carry the skeleton of someone twenty years older.
Here’s why it happens, how bad it gets for riders over 40, and exactly what you can do about it.
Why Cycling Weakens Your Bones Instead of Strengthening Them
Three mechanisms are quietly working against your skeleton every time you clip in.
No Impact, No Signal
Your bones remodel in response to mechanical stress. Load them and they get stronger. Don’t load them and they waste away.
Cycling is non-weight-bearing. The saddle carries your weight, the pedal stroke involves zero eccentric muscle contraction, and your skeleton never receives the “build more bone” signal. As performance coach Peter Gascoigne MSc puts it, “Cycling and sitting are the two worst combinations” for musculoskeletal health.
⚠️ Mountain bikers, by contrast, have significantly higher bone mineral density at all measured sites compared to road cyclists. The vibration and impact from trail riding provides exactly the stimulus that smooth tarmac never will.
Sweating Away Your Calcium
You can lose up to 150 mg of calcium per hour through sweat. On a three-to-four hour summer ride, that’s a serious chunk of your daily requirement gone through your jersey.
When intake doesn’t cover the deficit, your body pulls calcium directly from your bones.
Underfueling and Hormonal Collapse
RED-S (Relative Energy Deficiency in Sport) occurs when you chronically eat less than your training demands. It’s disturbingly common in a sport that rewards low body weight.
Male cyclists with low energy availability showed a bone density Z-score of -2.0, compared to -0.4 in well-fueled riders. A Z-score measures how you compare to the average for your age. A score of -2.0 means your bones are dramatically weaker than they should be.
Underfueling suppresses testosterone, IGF-1, and leptin, all hormones critical for bone turnover. Stack chronic cortisol from training stress on top, and your skeleton is being dismantled from multiple directions at once.
How Bad Does It Get for Cyclists Over 40
If you’re a masters cyclist, the numbers are uncomfortable.
Of those 84.2% who started with osteopenia or osteoporosis, 31.6% progressed to full osteoporosis over the study period. Only 5.6% of sedentary nonathletes deteriorated at the same rate. The person on the couch watching TV is losing bone slower than you are.
🚨 Some elite cyclists carry bone density scores typically associated with a 70-year-old, regardless of actual age. For those of us over 40, natural age-related bone loss is stacking directly on top of cycling-induced loss.
The Silent Problem
There’s no early warning system. In running or jumping sports, a stress fracture acts as a red flag. But road cycling produces no repetitive impact, so the first sign of low bone density is often a serious fracture from a crash that shouldn’t have broken anything.
Bone density loss can be slowed and partially reversed with targeted intervention. It takes consistent effort over months and years. The earlier you start, the more you can recover.
Get a Baseline
Book a DEXA scan. For athletes, the ACSM and IOC set the concern threshold at a Z-score of -1.0, stricter than the -2.0 used for the general population. A DEXA gives you a number to work from instead of guessing.
DEXA scans are available through your doctor or private clinics and typically cost under $150. That’s cheap insurance for your skeleton.
How to Protect Your Bones Without Giving Up Cycling
None of this requires quitting riding. It requires adding roughly two to three hours per week of complementary work.
1: Strength Training: The Non-Negotiable
Aaron Turner, PhD in Sports Performance and Continental team coach, recommends a minimum effective dose: 2 sessions per week, 16 to 30 total reps per exercise, at 80% of your one-rep max. Focus on compound lifts that load your spine and hips. Squats, deadlifts, and lunges hit exactly the skeletal sites most vulnerable to fracture.
A recent meta-analysis of concurrent training studies found that adding strength work delivered approximately a 5% improvement in cycling performance metrics. You get faster AND you protect your bones.
📢 GOOD NEWS: Masters cyclists who added weight training between study assessments lost significantly less bone mineral density than those who didn’t. The evidence is not ambiguous.
2: The Jumping Protocol
Short bursts of high-impact jumping are powerfully osteogenic. The protocol: 10 to 20 jumps, three times per day, three days per week. That’s about two minutes of total work. You can do it in the kitchen waiting for your coffee to brew.
These brief, high-impact forces are the exact signal your skeleton never gets from pedaling.
3: Fuel the Ride
Eating enough isn’t just about performance on the bike. It’s about keeping your skeleton intact.
If you’re sweating out up to 150 mg of calcium per hour, you need to replace it. Avoid chronic energy deficits, especially on long ride days. Your power-to-weight ratio means nothing if your femur snaps in a crash.
What the Pros Get Wrong About Bone Health
If world-class coaching, nutrition teams, and medical support could solve this problem, pro cyclists wouldn’t routinely show alarming bone density deficits. But they do. One study found professional cyclists had 9.1% lower bone mineral density than controls, with particularly alarming deficits in the lower back and hips.
These athletes have every resource available, yet the fundamental mechanisms are baked into the sport itself. Non-weight-bearing movement, massive sweat losses, and enormous energy demands create a bone health deficit that no amount of saddle time can fix. The problem isn’t inadequate support. It’s that cycling, by its nature, never loads the skeleton.
This isn’t limited to aging pros. A 2019 Norwegian study found that young elite cyclists in their teens and early twenties already had surprisingly weak bones. The damage starts accumulating from the very beginning of a cycling career, years before most riders ever think about bone health.
If the pros can’t out-train this problem on the bike alone, neither can we. The fix has to come from off the bike. Progressive teams are now building strength sessions and jumping protocols into their schedules. You don’t need a WorldTour budget to follow the same playbook.
Frequently Asked Questions About Cycling and Bone Density
Does cycling cause osteoporosis?
Not directly, but cycling removes the mechanical loading bones need to maintain density. Combined with calcium sweat loss and underfueling, it significantly increases the risk. 31.6% of master cyclists progressed to osteoporosis versus 5.6% of non-athletes.
Is mountain biking better for bones than road cycling?
Yes. Mountain bikers show significantly higher bone mineral density at all measured sites. Trail riding’s vibration and impacts provide loading stimulus that road surfaces cannot.
How often should cyclists get a DEXA scan?
Get a baseline scan, then repeat every one to two years. For athletes, a Z-score below -1.0 is the concern threshold per ACSM and IOC guidelines.
Can you reverse bone density loss from cycling?
Partially. Strength training and impact exercise can slow and partially reverse bone loss, but it takes months to years of consistent effort. The earlier you start, the better the outcome.
Do calcium supplements help cyclists with low bone density?
Adequate calcium intake matters, especially given sweat calcium losses during long rides. But supplements alone won’t solve it. Mechanical loading is the primary driver of bone remodeling.
Further Reading
- Olmedillas, H. et al. (2012). Cycling and bone health: a systematic review. BMC Medicine.
- Klomsten Andersen, O. et al. (2018). Bone health in elite Norwegian endurance cyclists and runners. BMJ Open Sport & Exercise Medicine.
- Hilkens, L. et al. (2023). Low bone mineral density and associated risk factors in elite cyclists. Medicine & Science in Sports & Exercise.
