Spaceflight

Physics

Aerospace engineering

Neuroscience

Astronomy

Psychiatry

Engineering

Physical therapy

Psychology

Maladaptation

Deconditioning

Weightlessness

Medicine

Nature Reviews Rheumatology

Space travel induces bone loss in crewmembers, who often develop signs of accelerated bone ageing. Here, Vico and Hargens describe the effects of space travel on the skeleton and explain how these findings can inform research into ageing and immobility. Space sojourns are challenging for life. The ability of the human body to adapt to these extreme conditions has been noted since the beginning of human space travel. Skeletal alterations that occur during spaceflight are now better understood owing to tools such as dual-energy X-ray densitometry and high-resolution peripheral quantitative CT, and murine models help researchers to understand cellular and matrix changes that occur in bone and that are difficult to measure in humans. However, questions remain with regard to bone adaptation and osteocyte fate, as well as to interactions of the skeleton with fluid shifts towards the head and with the vascular system. Further investigations into the relationships between the musculoskeletal system, energy metabolism and sensory motor acclimatisation are needed. In this regard, an integrated intervention is required that will address multiple systems simultaneously. Importantly, radiation and isolation-related stresses are gaining increased attention as the prospect of human exploration into deep space draws nearer. Although space is a unique environment, clear parallels exist between the effects of spaceflight, periods of immobilization and ageing, with possibly irreversible features. Space travel offers an opportunity to establish integrated deconditioning and ageing interventions that combine nutritional, physical and pharmaceutical strategies.

Skeletal changes during and after spaceflight