On January 30 the New York Times published a story “Can Low-Impact Sports Like Cycling Be Putting Your Bones at Risk?”. It refers to a Norwegian study that compared DXA scans of twenty elite runners vs. 19 elite cyclists. It concluded that the cyclists had significantly lower Bone Mineral Density (BMD) compared to the runners despite having similar calcium intake. One cyclist had osteopenia and another ten had BMD more than one standard deviation below the norm, despite most of the cyclists performing weight training as part of their training (weight training has been shown to build bone).
Note that most of the cyclists were in their 20’s and trained 900 hours per year (17 hours per week), so most of us don’t have to worry about being in this cohort, although the study authors did add a comment that “a higher prevalence of osteopenia and osteoporosis has been displayed in highly trained master cyclists” (90%). One commenter in the article noted that significant calcium loss can occur because of sweating. The study authors referenced another study that suggested a “calcium-rich meal 90 min prior to intensive exercise”. Note that elite cyclists have a unique focus on low BMI (or high watt/kg) that might skew the results. The study authors conclude “it raises the question whether interventions to increase BMD in this population should be considered”.
The study was small and the NYT did a disservice by raising FUD (fear, uncertainty and doubt) without putting the study in context or offering solutions. Low BMD does not necessarily mean low bone strength. Trainer Road emphasizes good nutrition and appear to be fond of DEXA scans (that determines, among other things, bone density), but are there other studies that we should know about or should the 4 watt per kilogram crowd be concerned?