Learning From Human Responses to Deconditioning Environments: Improved Understanding of the “Use It or Lose It” Principle

Abstract

Physical activity, mobility or patterned mobility (i.e., exercise) is intrinsic to the functioning of Homo sapiens, and required for maintenance of health. Thus, systems such as the musculoskeletal and cardiovascular systems appear to require constant reinforcement or conditioning to maintain integrity. Loss of conditioning or development of chronic deconditioning can have multiple consequences. The study of different types of deconditioning and their prevention or reversal can offer a number of clues to the regulation of these systems and point to how deconditioning poses risk for disease development and progression. From the study of deconditioning associated with spaceflight, a condition not predicted by evolution, prolonged bedrest, protracted sedentary behavior, as well as menopause and obesity and their consequences, provide a background to better understand human heterogeneity and how physical fitness may impact the risks for chronic conditions subsequent to the deconditioning. The effectiveness of optimized physical activity and exercise protocols likely depend on the nature of the deconditioning, the sex and genetics of the individual, whether one is addressing prevention of deconditioning-associated disease or disease-associated progression, and whether it is focused on acute or chronic deconditioning associated with different forms of deconditioning. While considerable research effort has gone into preventing deconditioning, the study of the process of deconditioning and its endpoints can provide clues to the regulation of the affected systems and their contributions to human heterogeneity that have been framed by the boundary conditions of Earth during evolution and the “use it or lose it” principle of regulation. Such information regarding heterogeneity that is elaborated by the study of deconditioning environments could enhance the effectiveness of individualized interventions to prevent deconditions or rescue those who have become deconditioned.

Extended effects of a wearable sensory prosthesis on gait, balance function and falls after 26 weeks of use in persons with peripheral neuropathy and high fall risk—The walk2Wellness trial

“…Although such interventions may improve balance outcomes, effects are essentially compensatory since they do not address the root cause of the balance problem in these patients, namely their impaire plantar sensation due to PN. Furthermore, any exercise activity would need to be maintained on a regular basis long-term or benefits would gradually be lost ( Melzer and Oddsson, 2013 ; van Waart et al, 2015 ), sometimes referred to as the “use it or lose it” principle ( Hart, 2021 ). This phenomenon is problematic because individuals sometimes become sedentary due to health problems unrelated to their balance disorders.…”

Extended Effects of a Wearable Sensory Prosthesis on Gait, Balance Function and Falls After 26 Weeks of Use in Persons with Peripheral Neuropathy and High Fall Risk – The walk2Wellness Trial

“…Although such interventions may improve balance outcomes, effects are essentially compensatory since they do not address the root cause of the balance problem in these patients, namely their impaire plantar sensation due to PN. Furthermore, any exercise activity would need to be maintained on a regular basis long-term or benefits would gradually be lost (Melzer and Oddsson 2013, van Waart, Stuiver et al 2015), sometimes referred to as the “use it or lose it” principle (Hart 2021). This phenomenon is problematic because individuals sometimes become sedentary due to health problems unrelated to their balance disorders.…”

Creating an Optimal In Vivo Environment to Enhance Outcomes Using Cell Therapy to Repair/Regenerate Injured Tissues of the Musculoskeletal System

“…Osteoarthritis is both a disease of mechanics [ 180 ] and inflammation [ 181 ], and of the whole joint and not just the articular cartilage [ 182 , 183 ]. The term osteoarthritis is actually an umbrella term that encompasses several subtypes of OA including post-traumatic OA, metabolic OA associated with obesity reviewed in [ 20 , 42 , 181 , 184 ], post-menopausal onset OA discussed in [ 42 ], with idiopathic OA a large subpopulation of patients for which a link to a cause has not been clearly defined. Thus, OA, which can develop if a cartilage defect is not repaired, is heterogeneous and complex, and one cell therapy solution likely will not apply to all subtypes of the disease.…”

“…Bone can respond to changes in loading and become strengthened [ 17 , 18 , 19 ]. In contrast, several MSK tissues can undergo atrophy if not used appropriately and become “deconditioned” [ 20 ]. Following an injury, MSK tissues often requires immobilization (e.g., putting a leg in a cast when a bone is broken) which is a “deconditioning” environment for healing to initially take place.…”