The atrophy of bone mass in low gravity has vexed NASA for decades. Osteopenia, or bone loss, from weight-bearing structures and crucial trabecular bone is a major health consideration for anyone spending a long time in a reduced-gravity environment. So far, NASA and other agencies have attempted to outrun this deterioration by assigning astronauts a combination of anti-resorptive drugs, like bisphosphonates, and resistive exercise regimens. However, each of these solutions has serious downsides––risk of side effects and injury, respectively––and no combination of both has proved effective at maintaining 100% of bone mass in space.
That’s where Ben Lecomte comes in. His historic attempt to swim across the Pacific Ocean means he will be spending roughly eight hours each day doing intensive aerobic exercise in a buoyant environment akin to 0G. Seizing an unprecedented research opportunity, physicians and researchers worked together to collect data on his skeleton’s mineral density using a technique called Dual-energy X-ray Absorptiometry (DXA or DEXA for short), before he departed. When he returns, the procedure will be repeated, and the researchers will note any effects on his bone density and distribution. Will he lose mass from structures he isn’t using to bear weight, such as his hip and heel bone? Will all the exercise he is doing be enough to maintain his bone mass, even though it is mainly aerobic rather than resistive? The answers Ben provides may lead to a better protocol to protect the skeleton, an essential step toward long-term spaceflight.