Sedative Agents, Synthetic Torpor, and Long-Haul Space Travel-A Systematic Review

Background: The resurgence of interest in space exploration has highlighted the potential use of an induced torpor-like state for long-duration human space missions. Sedative agents, historically utilized for inducing unconsciousness and inactivity in clinical procedures since the mid-1700s, are being explored as tools to facilitate synthetic torpor for space travel. Objective: To assess the feasibility of adapting sedative agents to induce and maintain a torpor-like state for extended space missions, addressing the physiological and pharmacological challenges, and evaluating their potential protective effects against the harsh conditions of spaceflight. Torpor is characterized by reduced body temperature and metabolic rate, often accompanied by decreased brain function, heart rate, respiratory rate, circulation, and motor activity. These features are critical for mitigating the physiological demands of long-duration space missions. Methods: This systematic review evaluates current research on the mechanisms regulating torpor induction, maintenance, and arousal. It also examines the pharmacokinetics and pharmacodynamics of sedative agents, particularly inhalation anesthetics, and their potential to mimic torpor-like physiological states. Findings: Sedative agents are well characterized for their effects during anesthesia phases but present significant challenges in replicating the protective and metabolic features of torpor. Adapting these agents for spaceflight requires overcoming obstacles such as prolonged drug administration, limited arousal control, and counteracting the adverse effects of microgravity and radiation exposure. Synthetic torpor offers potential as a countermeasure to the challenges of long-haul space exploration. However, its implementation requires addressing the limitations of current sedative agents and optimizing them for extended use. Inhalation anesthetics demonstrate promise but require further investigation into their safety, efficacy, and long-term effects in spaceflight conditions. Conclusion: Inducing a torpor-like state with sedative agents represents a promising avenue for supporting long-duration human space missions. Further research is needed to refine the pharmacological approaches, ensure safety, and enhance the protective effects against spaceflight stressors.