Modeling the dynamics of energy imbalance: The free radical theory of aging and frailty revisited

The role of oxidative stress in aging and the newly conceptualized vision of frailty is of great interest for the possibility to define a framework able to explain the several modifications observed in all biological molecules along with age. In this review, the impact of oxidative stress is considered in aging processes as well as in frailty, the geriatric concept of declined capacity to cope with any stressor, leading to a status of reduced ability to maintain the homeostatic balance. Although some pharmacological and behavioral approaches have been proposed, we are still lacking efficacious management able to prevent and avoid frailty. This represents a fundamental challenge for future research in this field. [Display omitted] •The role of oxidative stress in aging and frailty is proposed as a framework for age-related biological modifications.•A uniform definition of frailty, its measure, and assessment are needed to have replicable markers of aging and frailty.•Oxidative stress, swinging from eustress to damage, is one of the pillars of life, and its modulation may stop the frailty spiral.