Complex exercise interventions to modify risk of functional loss and disability in older adults

Research output: ThesisPh.D. thesis

Abstract

Background Disability in self-care and basic household activities is a major threat for the quality of life of older people, and for the sustainability of the health care sector. Disability arises from the complex interactions between a person with a health condition and the persons’ environmental and personal factors. Increasing the level of daily physical activity (PA-level) of insufficiently active and sedentary older adults is critical to reduce the risk of developing disability. Resistance training may play a key role in preventing disability as it causes adaptations in the neuromuscular system by increasing intrinsic capacities such as
muscle strength and power which are essential for performing independently discrete functional tasks and mobility (i.e., rising from a chair, gait). Yet, it is still unclear whether these training-induced changes translate into reduced self-reported disability. Further, many older adults perceive barriers related to health, environmental- and personal factors, restraining them from initiating and being adherent with exercise programs and, in general, for being more physically active. Combining community-based exercise programmes with behavioural self-management strategies (SMS) to tackle barriers for PA may increase programme
adherence and PA-levels during intervention and promote long-term sustainability of newly acquired PA-behaviours after the end of the programme. However, more evidence is needed on the short and long-term effects of exercise alone and in combination with multiple domains SMS to improve functional capacity and self-reported disability outcomes in older adults. This thesis aimed to investigate the effect of complex exercise interventions on objective measures of functional capacity and self-reported disability in +65-year older adults with different risk-profiles for disability.

Methods The isolated effects of resistance training on self-reported disability in older adults with pre-existing functional limitations or disability were first investigated in a systematic review and meta-analysis. The study used meta-regression to additionally explore the associations between reduced disability and changes in objectively assessed knee extensor muscle strength, gait capacity, and lower body functional capacity (Study I). Next, short-term, and long-term effects of complex interventions combining a) two weekly sessions of exercise with resistance training as a core component with b) SMS to tackle barriers for PA, were investigated in two randomized controlled trials on self-reported disability (the short form of the Late-Life Function and Disability Index), ADL/IADL and functional capacity (Short Physical Performance Battery) (study II and III). Study II enrolled physically inactive participants to one of three intervention arms: a) 4-months exercise combined with 7- months SMS focusing on reducing sedentary behaviour (SB) and increasing PA, b) the exercise programme only, and a c) control condition. Assessments took place at baseline, at 4-months, at 16-months, and at 22-months. Study III enrolled participants with early markers of functional decline to one of two intervention arms: a) 3-months exercise combined with 6- months SMS, or b) the SMS programme only. Assessment took place at baseline, 3-months, and 6-months. Interventions were conducted in community-settings, and participant recruitment was embedded in nationally regulated preventive pathways.

Results Pooled effects from fourteen RCTs showed that structured resistance training had moderate size effects on reducing disability in older adults with pre-existing functional 12 limitation or disability compared to passive or sham control (SMD: 0.59). Higher age predicted larger effects. Notably, improvements in self-reported disability were strongly associated with increased lower body functional capacity assessed by chair-rise tests combined with gait and or balance. 

Participants in all intervention groups improved SPPB-scores at the follow-ups most distant from baseline (22 and 6 months in study II & study III, respectively). Superior effect of the combined interventions was only confirmed immediately after exercise (Study II & Study III). The exercise-only group did not have superior increases in SPPB-score compared to the control group at any timepoint. No effect of exercise (including resistance training) on selfreported disability were found in studies on community-dwelling older adults (study I) or in the two experimental trials (study II & study III).

Conclusion This thesis confirmed that resistance training has moderate size effects on selfreported disability in older adults with pre-existing limitations or disability. There was no consistent evidence for an effect in community-dwelling older adults. Combining exercise with SMS led to superior short-term effects compared to single-component interventions and control. Behaviour-change strategies such as SMS may be a promising strategy to increase short term effects of exercise interventions on functional capacity in community-dwelling adults.
Original languageEnglish
Awarding Institution
  • University of Southern Denmark
Supervisors/Advisors
  • Caserotti, Paolo, Supervisor
Date of defence8. Apr 2022
Publisher
DOIs
Publication statusPublished - 21. Feb 2022

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