Aging-like metabolic and adrenal changes in microgravity: State of the art in preparation for Mars.

Endocrine and metabolic changes that typically accompany aging on Earth have been consistently observed in space. Support for the role of gravity in aging has mostly come from ground simulation studies in head down bed rest. However, uncertainties remain and have to be resolved in planning for the ambitious enterprise of sending humans to Mars and back. Stress-related corticosteroid changes and metabolic adaptation to microgravity and their relationship with aging are the object of the present review mostly, albeit of course non exclusively, coming from the personal experience of the authors. The picture coming out of it is that of some, not easily proven, stress-induced cortisol increase accompanied by insulin resistance, both of which represent typical aging-like phenomena mediated by chronic low-grade inflammation. This suggests the need for humans to consider the long journey to safely land, live and work on Mars by taking advantage of integrative medicine solutions including synthetic torpor and/or continuous self-monitoring of eating, sleeping, moving to enable remotely supervised self-treatment.