Greater physical fitness (Vo2Max) in healthy older adults associated with increased integrity of the Locus Coeruleus-Noradrenergic system

Abstract

Abstract Physical activity (PA) is a key component for brain health and Reserve, and it is among the main dementia protective factors. Robertson proposed that the upregulation of Locus Coeruleus-noradrenergic (LC-NA) system might be a key aspects for building reserve and resilience to neurodegeneration. PA elicits an enhanced catecholamine response, in particular Noradrenaline (NA). By increasing physical commitment, greater amount NA is synthetised in response to higher oxygen demand. More trained individuals show greater capabilities to carry oxygen resulting in greater Vo2max (a measure of oxygen uptake and physical fitness indicator). In the current study, we hypothesised that greater Vo2 max could be related to greater LC-NA MRI integrity. As hypothesised, greater Vo2max related to greater LC integrity across 41 healthy adults (age range 60–72). As a control procedure, when the analyses were repeated for the other neuromodulators’ seeds (Serotonin, Dopamine and Acetylcholine) weaker associations emerged. The newly established link between Vo2max and LC-NA system offers further understanding of the neurobiology underpinning Reserve in relationship to PA. While this study supports Robertson’s theory proposing the upregulation of the noradrenergic system as a possible key factor building Reserve, it also provide ground for increasing LC-NA system resilience to neurodegeneration via Vo2max enhancement.