From the Desk of Dr. Levin:
The pro-cycling peloton whirs along, a rhythmic symphony of wind in wheels, chains on cogs. At dissonant intervals, crashes add the screech of metal on concrete, the percussion of tires exploding, and the snap of bones being broken. That’s right pro cyclists fall down and break stuff. A lot. While people break bones all the time, and cycling crashes can be violent affairs, from a non-scientific perspective it seems as though pro-bike racers as a group are a pretty brittle bunch. What gives?
Actually, from a scientific point of view cyclists really are frail. Bone mineral density (BMD) is a measurement of bone hardness. Low BMD is associated with increased rate of fractures. Just in the past year one study measured BMD in pro-cyclists and found that they had up to 20% lower bone mass than a group of young healthy men. In another study looking at the pro peloton, researchers found that 2/3 of the riders they analyzed had abnormally low BMD values.
It’s not just the pros. A study of amateur cyclists found similar results And (this one’s a little close to home) a seven year study of masters racers found a steady decline in bone mass and low bone densities throughout the study period.
Why are cyclists—from the world’s best to l’il old me—at such high risk for low bone density, osteoporosis and brittle bones? There are two factors at play which predispose cyclists to low BMD. Luckily both are relatively easy to remedy.
First, cycling as an endurance exercise puts increased nutritional demands on athletes. This means that calcium and vitamin D, which are essential to healthy bone formation, are at a premium for cyclists. Calcium, along with sodium is one of the elements lost in sweat. It’s important, therefore, to make sure that calcium containing foods (dairy, salmon, peas, beans, supplements) are part of your regular diet. However, calcium deficiency alone certainly isn’t the only factor in cycling associated bone loss, because in many of the cycling studies cyclists actually had high levels of dietary calcium.
The second, and more important factor leading to bone weakness among cyclists is that cycling is non weight bearing exercise. Bones need impact, loading and unloading, to stimulate healthy bone turnover and bone growth. That’s why bone density studies done for impact sports like soccer, tennis, and football players all showed increased bone mass compared to non athletes as well as cyclists. Strength training— weight lifting, pleiometric exercises like jumping rope, and medicine ball torture sessions all can be an important part of any cyclist’s training regimen. In fact, one study showed that cyclists who included weight bearing exercise as part of their training did not lose bone mass compared to cycling only regimens. Bottom line: train like a pro, race like a pro, but try to avoid having collarbone surgery like a pro. Eat smart, get to the gym, and keep the rubber side down.