Cycling: bad for your bone health?

There’s no doubt that cycling is great for health and cardiovascular fitness, and good for the environment to boot.

Despite these benefits, however, some studies indicate that cycling might not be ideal for long-term bone health in those who don’t incorporate other types of exercise into their training programmes. This is because the smooth, non-weight-bearing nature of cycling lacks the stresses and impacts that we now know are required to build maximum bone density.

Accumulating maximum bone density is important because the higher your bone density during your early-mid adult years, the lower the risk of developing osteoporosis (quite literally porous bones) in later life, which can have devastating consequences for health and mobility.

To date, there has been no definitive study in this area, but now Spanish scientists have completed a meta-review (combined review of all previously published scientific studies in this area) on cycling and bone health.

The science
The researchers pooled all the previous studies published on bone mass and/or bone metabolism in cyclists up to April of last year. These 31 studies included:

Descriptive studies – studies that simply reported on observations without testing a theory; cross-sectional studies – studies that collected data on a group or subset of cyclists at a particular point in time; longitudinal studies – studies that tracked a group of cyclists’ bone health over a period of time; intervention studies – studies where an intervention was carried out in a group of cyclists and subsequent bone mass/density assessed. All the data was statistically analysed.

In a nutshell
The first thing the researchers discovered was that the picture was far from simple. The age, gender, experience and the type of cycling performed by cyclists were all shown to play a role in determining the level of bone density. For example, mountain bikers were less affected by bone mass loss than their road riding counterparts. Road cyclists who practised other sports (eg, running) were also less affected by bone mass losses.

However, the main conclusion was unavoidable: adult road cyclists participating in regular cycling training (and no other type) had low bone mineral density in key regions (such as the lumbar spine).

So what?
This study might not present new data, but it solidifies and confirms what we’ve already discovered – that road cyclists who don’t practise other sports or activities are at real risk of developing reduced bone mass, which could place them at greater risk of osteoporosis in later life. This doesn’t seem related to diet or hormone levels of cyclists, as no evidence of this was observed in any of the studies.

Instead, the researchers concluded that the cause was almost certainly related to spending long hours in a weight-supported position on the bike, in combination with the necessary enforced recovery time that involves a large amount of time sitting or lying down (especially for those at competitive level).

The message is clear: while cycling is great for your health overall, you need to top it up with a bit of weight-bearing exercise (running, resistance training etc) to keep your bones in tip-top condition.

BMC Med. 2012 Dec 20;10(1):168. [Epub ahead of print]

This article was first published in the February 14 issue of Cycling Weekly. You can also read our magazines on Zinio, download from the Apple store and also through Kindle Fire.