Metabolic Rate and Perceived Exertion of Walking in Older Adults With Idiopathic Chronic Fatigue.
Fatigue is a common complaint in older adults, often not associated with underlying medical conditions. The purpose of this study was to investigate metabolic rate (MR) of walking, walking performance, and perception-based exertion during walking in older adults with and without idiopathic chronic fatigue (ICF).



20 older adults (aged 70.8±4.9 years), reporting 2 SD above normative values of the Functional Assessment of Chronic Illness Therapy-Fatigue scale and without overt health conditions that explained their symptoms, were compared with 25 age-matched older adults (73.2±5.1 years) without fatigue symptoms. Participants walked 400 m at a rapid pace on a 20-m course. On a separate visit, oxygen consumption was measured during treadmill test at standard (40.2 m/min), preferred paces (40-83 m/min) and peak capacity. Ratings of perceived exertion (RPE) were measured at each treadmill stage and after each lap of the 400-m walk test.



During the 400-m walk test, individuals with ICF showed lower overall walking speed and reported a steady increase in RPE with no change observed in non-fatigued group (1.63±1.72 vs 0.27±0.68, p < .01). Similar findings on RPE were noted on treadmill test. Gross MR, mass-specific MR, mass-specific net MR, and MR as a percent of peak oxygen consumption of walking were similar between groups during standard, preferred paces and peak capacity on treadmill.



This study suggests that ICF in older adults is not related to elevated metabolic cost of walking. Higher RPE without concomitant decreases in performance indicate a potential disconnect between metabolic output and sensations during movement.
Department of Aging and Geriatric Research, Institute on Aging, University of Florida, Gainesville. v.valiani@ufl.edu.|Dipartimento Interdisciplinare di Medicina, Clinica Medica Cesare Frugoni, University of Bari Aldo Moro, Italy.
Vincenzo
V
Valiani
Department of Aging and Geriatric Research, Institute on Aging, University of Florida, Gainesville.
Duane B
DB
Corbett
Department of Aging and Geriatric Research, Institute on Aging, University of Florida, Gainesville.
Jeffrey D
JD
Knaggs
Department of Aging and Geriatric Research, Institute on Aging, University of Florida, Gainesville.
Todd M
TM
Manini
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D002908:Chronic Disease; D004185:Disability Evaluation; D004734:Energy Metabolism; D005080:Exercise Test; D005221:Fatigue / Q000503:physiopathology*; D005260:Female; D015577:Geriatric Assessment; D006801:Humans; D010101:Oxygen Consumption / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology*; D016138:Walking / Q000502:physiology*; D000072797:Walking Speed / Q000502:physiology
Aging; Disability; Fatigue; Metabolic rate; Perceived exertion