Does heart rate variability reflect brain plasticity as a likely mechanism of adaptation to space mission?

Abstract

In space medicine, the definition of “health” is considered as the ability of a crew member to carry out a high-quality space mission program and at the same time retain enough functional reserves for readaptation to earth conditions after it is completed (Baevsky et al., 2013). Professional space crews are formed from specially selected, practically healthy people trained to work in changed conditions and under constant stress (Kovacs and Shadden, 2017). Monitoring of their functional state is based on the assessment of changes within the physiological norm, where the main ones are shifts (reorganizations) occurring in the mechanisms of regulation and developing at the information-temporal or informationenergy levels of the body (Baevsky et al., 2011). In this sense, the individual approach of space medicine to health assessment can be seen as a prerequisite for modern personalized medicine (Dietrich et al., 2018; Pavez Loriè et al., 2021). On the one hand, the structural elements of the human body are a system of independent components, on the other hand, they are characterized by complex interactions (Burggren and Monticino, 2005; Grenfell et al., 2006), therefore, the creation of a unified concept of health in space medicine is an integrative task that can be solved from the standpoint of systems biology. The totality of space flight factors requires the human body to exert constant tension on its regulatory systems to maintain homeostasis (Baevsky et al., 2014). The complex impact of stress factors leads to the fact that ever-higher levels of control over the physiological functions of the body are involved in the adaptation process (Baevsky et al., 2007; Baevsky et al., 2009). This ensures the necessary coordination of various systems and processes within the framework of a single goal—balancing the body with the environment (Baevsky and Chernikova, 2016). One of the characteristics of a system that ensures the quality of its functioning is plasticity, which allows it to quickly cope with the challenges of a changing environment (Goldberger, 1991; Beckers et al., 2006; McCraty et al., 2009; Smith et al., 2017). First of all, this is due to the ability of neurons, neural structures, and neural networks of the brain to dynamically change structural and functional characteristics and modify response patterns in response to changes in external conditions and afferent stimuli (Slenzka, 2003; Pearson-Fuhrhop and Crame, 2006). OPEN ACCESS