Ask the Expert: Does Indoor Cycling Help Bone Health?

A common question we hear among cycling instructors is whether cycling can help prevent osteopenia or osteoporosis. While cycling offers numerous health benefits, when it comes to improving bone density, the answer might surprise you.

This article from the ICA archives first appeared in 2012. Not only is its message just as relevant today, the advice is still fresh and up-to-date. Now, over a decade later, I’ve had my own wake-up call on this topic—and if my story serves as a reminder or inspiration to even one of you, then sharing it will have been worth it.

Even though I’m a part-time personal trainer, cycling has long been my primary form of exercise. I did some weight training in the past, but mostly for the upper body and not very regularly. About 18 months ago, I had my first bone density test and was diagnosed with osteopenia. That news was a huge motivator. Starting the very next day, I committed to adding weight-bearing exercises like squats, step-ups, and lunges to my weekly routine, steadily increasing the weight over time. (Due to a spinal fusion and two metal rods in my back, I cannot do high-impact activities like running or jumping, so lifting heavy is my only option.) But here’s the kicker: I started tracking every pound I lifted. By the end of the first year, I’d cumulatively lifted 625,000 pounds (just with these three exercises)!

Now, I’m not saying this to brag (OK, maybe just a little—it is kind of cool to say you’ve lifted over half a million pounds in a year), but because that obsessive tracking is what kept me consistent. Seeing those numbers grow became its own little competition with myself, and it reminded me that I was taking control of my bone health one rep at a time.

Eighteen months later, I’m still going strong. I have a few years to go before my next bone density test but I’m determined to approach it with the confidence that comes from a consistent, targeted effort. If you’ve been putting off weight-bearing exercises or need a nudge to start, let this be a motivator for you, too.

I know I’m not alone in facing these challenges. Maybe my story will inspire you or someone you know to take similar action. Whether it’s tracking your lifts, your planks, or even your steps, finding a system that keeps you accountable is what matters most.

Now, if you’ll excuse me, I’ve got some squats to do—and maybe a celebratory spreadsheet update afterward. Melissa Marotta’s article below serves as the perfect reminder of why all of us need to prioritize this effort!

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This question came from an ICA member:
“One of my riders asked me if indoor cycling is weight-bearing enough to be beneficial for someone dealing with osteopenia. My guess was yes (especially when climbing), but I told her I’d investigate further. Any thoughts, insights, or studies I could pass along?”

It’s an important question—and one that affects not just our students but many of us as well. To provide the best answer, I turned to an expert.

At the time this article was written, Melissa Marotta Houser was a senior medical student at the University of Vermont College of Medicine. Today, she practices family medicine in Vermont. Melissa brought a unique perspective to this topic as both a longtime STAR 3 Spinning® instructor and a certified personal trainer (American Council on Exercise [ACE]). Her firsthand experience with indoor cycling, combined with her medical expertise, made her the perfect person to tackle this question.

Melissa’s dedication to research is evident in her work. She was the principal investigator of a clinical trial exploring the use of exercise heart rate monitors in treating anxiety, and her other research focuses include health literacy, patient-physician communication, and the psychological benefits of heart rate training. You’ll see that same depth of insight in her article below.

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The Risks of Weak Bones

Approximately 44 million Americans have weak bones, with half of them aged 50 or older. Why is this a concern? Low bone density significantly increases the risk of fractures, whether from minor falls or even something as simple as rolling over in bed.¹  Fractures can have severe consequences, including immobility, increased nursing home placements, and even death—one in five women and one in three men who experience a hip fracture die within the first year.²

Risk factors for low bone mass (“osteopenia,” or “osteoporosis” for more severe bone loss and higher fracture risk) include age, low body weight, insufficient calcium and vitamin D, low estrogen levels (as seen with menopause), prolonged use of certain medications (e.g., steroids, anti-seizure drugs), smoking, excessive alcohol intake, family history of osteoporosis, and a lack of weight-bearing exercise.³

Once bone mass is lost, reversing it is incredibly difficult. Prevention is far more effective and starts with managing the controllable risk factors early in life and as we age. Weight-bearing activity is most impactful in building bone strength before age 30, when peak bone mass is typically achieved.⁴ However, research shows that the benefits of early weight-bearing activity only continue if such activities are maintained throughout adulthood.⁵

What is weight-bearing exercise?

Weight-bearing exercise involves activities where your bones support your body weight, stimulating bone-building cells called osteoblasts.⁶ These cells respond to the mechanical stress caused by high-impact activities, laying down more bone to strengthen areas under strain.⁷

Activities like jogging, step aerobics, kickboxing, jumping rope, dancing, hiking, basketball, plyometrics, racket sports, stair climbing, yoga, tai chi, weightlifting, and even mowing the lawn can stimulate osteoblast activity. The key is applying moderate to high force on the bones.⁸

You might notice cycling isn’t on this list. That’s because, in cycling, your bike supports most of your body weight, similar to how water supports your weight in swimming. While both are excellent for cardiovascular health, they’re not ideal for improving bone density.

Of note, there is some recent evidence that highly trained, competitive cyclists actually have decreased bone mineral density. It’s unclear whether this is due to something specific to the sport of cycling causing increased bone turnover, or simply the absence of additional non-cycling (cross-training) weight-bearing activities. Joe Friel has completed an outstanding review of recent literature specific to competitive/professional cyclists; for more on that, please refer to his article “Bones and Cyclists.”

Does Indoor Cycling Count?

The short answer: “Kind of, but not really.”

One advantage of training on a fixed-gear indoor bike with a weighted flywheel is the ability to train against resistance, which helps build leg muscle strength, endurance, and other fitness benefits. Resistance training improves cycling performance on the road⁹, and stronger muscles contribute to more stable joints. However, for stimulating osteoblast activity and bone growth, it’s essential for bones to support most of your body weight. While the added weight of a 40-pound flywheel offers resistance, the seated position on an indoor bike doesn’t provide the necessary skeletal stress for significant bone-building.

Prolonged climbing out of the saddle might have some benefit. For example, mountain bikers show increased bone mineral density compared to road cyclists and non-cyclists, although this finding comes from a study with a very small sample size.¹⁰ Still, resistance training alone may not enhance bone density as effectively as high-impact activities like jogging.¹¹ Only the bones exposed to specific stress adapt with increased density.¹² In fact, even walking might not apply enough skeletal loading to prevent bone density decline, according to recent reviews.¹³

Despite this limitation, the cardiovascular, muscular, and psychological benefits of indoor cycling are undeniable. Physical activity improves overall health, including every organ system, and enhances musculoskeletal stability. Strong muscles not only protect joints but also reduce the risk of hip fractures by providing stability.¹⁴ Improved balance further decreases fall risk¹⁵, though outdoor cycling offers more balance training than indoor cycling.

How Can Cyclists Reduce the Risk of Osteoporosis?

While there’s no one-size-fits-all exercise prescription to reduce osteoporosis risk, several key themes emerge:

1. Cross-Train Regularly
   Incorporate a variety of activities from the list of weight-bearing exercises mentioned earlier. Cross-training helps prevent overuse injuries, targets different muscle groups, and keeps workouts fresh and engaging.
2. Add Strength Training
   The American College of Sports Medicine (ACSM) recommends strength training twice weekly for all major muscle groups: 8–12 repetitions for adults under 65 and 10–15 repetitions for those over 65. Avoid training the same muscle groups on consecutive days to allow for recovery.¹⁶
3. Consult Your Doctor
   Your doctor can recommend personalized strategies, including appropriate calcium and vitamin D intake, timing of bone mineral density tests, and, if necessary, medications to slow bone loss.
4. Avoid Smoking and Excess Alcohol
   Both negatively affect bone health. Smoking increases fracture risk, and excess alcohol consumption reduces bone formation.

Summary

While heavy resistance and out-of-the-saddle climbing in indoor cycling may offer some weight-bearing benefits, they’re not as effective as high-impact activities like jogging for improving bone density. Cross-training with weight-bearing and non-weight-bearing activities can help balance the benefits of each while minimizing injury risks.

The goal is to create a well-rounded exercise plan tailored to your needs and priorities. Remember, the key is balance—not just on your bike, but in your approach to fitness and bone health.

 

REFERENCES
(1) Lewiecki EM (2010). Prevention of osteoporosis. Up To Date, 10 September 2010. www.uptodate.com
(2) Barry DW, Kohrt WM (2008). Exercise and the Preservation of Bone Health. Journal of Cardiopulmonary Rehabilitation and Prevention, 28(3): 153-162.
(3) Lewiecki EM (2010). Prevention of osteoporosis. Up To Date, 10 September 2010. www.uptodate.com
(4) Ibid.
(5) Bergmann P, Body JJ, Boonen S, Boutsen Y, Devogelaer JP, Goemaere S, Kaufman J, Reginster JY, Rozenberg S (2010). Loading and Skeletal Development and Maintenance. Journal of Osteoporosis, Vol 2011:786752.
(6) Lewiecki EM (2010). Prevention of osteoporosis. Up To Date, 10 September 2010. www.uptodate.com
(7) Barry DW, Kohrt WM (2008). Exercise and the Preservation of Bone Health. Journal of Cardiopulmonary Rehabilitation and Prevention, 28(3): 153-162.
(8) Ibid.
(9) Yamamoto LM, Klau JF, Casa DJ, Kraemer WJ, Armstrong LE, Maresh CM (2010). The Effects of Resistance Training on Road Cycling Performance Among Highly Trained Cyclists: A Systematic Review. Journal of Strength & Conditioning Research, 24(2): 560-566.
(10) Warner SE, Shaw JM, Dalsky GP (2002). Bone mineral density of competitive male mountain and road cyclists. Bone, 30(1): 281-286.
(11) Rector RS, Rogers R, Ruebel M, Widzer MO, Hinton PS (2009). Lean body mass and weight-bearing activity in the prediction of bone mineral density in physically active men. Journal of Strength & Conditioning Research, 23(2): 427-435.
(12) Barry DW, Kohrt WM (2008). Exercise and the Preservation of Bone Health. Journal of Cardiopulmonary Rehabilitation and Prevention, 28(3): 153-162.
(13) Martyn-St James M, Carroll S (2008). Meta-analysis of walking for preservation of bone mineral density of postmenopausal women. Bone, 43(3): 521-531.
(14) Lewiecki EM (2010). Prevention of osteoporosis. Up To Date, 10 September 2010. www.uptodate.com
(15) Barry DW, Kohrt WM (2008). Exercise and the Preservation of Bone Health. Journal of Cardiopulmonary Rehabilitation and Prevention, 28(3): 153-162.
(16) Haskell WL, Lee I, Pate RR, Powell KE, Blair SN, Franklin BA, Macera CA, Heath GW, Thompson PD, Bauman A (2007). Physical Activity and Public Health: Updated Recommendation for Adults from the American College of Sports Medicine and the American Heart Association.  http://www.acsm.org/

 

Research by Joe Friel and other endurance athletes:

As noted in the article, Joe Friel discussed the subject as it relates to cyclists, and provided a list of studies on his blog in February 2011. Here is his first post on the subject. He then followed up with another post in March 2011. Another excellent series on bone health in athletes is on John Post, MD’s blog (he is the contributing medical director for both Training Bible Coaching and Rock Star Triathlete). He has written two articles on bone health, part 1 and part 2. Make sure to poke around his blog for a lot of other great information.[/show_if]