TY - JOUR
T1 - Relationships of cardiac, pulmonary, and muscle reserves and frailty to exercise capacity in older women
AU - Weiss, Carlos O.
AU - Hoenig, Helen H.
AU - Varadhan, Ravi
AU - Simonsick, Eleanor M.
AU - Fried, Linda P.
N1 - Funding Information:
the original study for this research was funded by the National Institute on Aging grant N01AG12112 and was supported by the National Institutes of Health grant NCRR M01-RR00052. C.O.W. was funded by the Robert Wood Johnson Harold Amos Medical Faculty Development Program and by NIA P30AG021334-04. L.P.F. was funded by NIA 5R37AG019905-08.
PY - 2010/3
Y1 - 2010/3
N2 - BackgroundA decline in exercise capacity (EC) is a characteristic of frailty. We hypothesized that decline is the effect of decrements in several physiological systems. We assessed whether the relationship of three main physiological systems-cardiac, pulmonary, and musculoskeletal-to EC is independent or interactive and whether their effect on EC varies with respect to frailty status.MethodsObservational study of 547 disabled women aged 65 years and older (Women's Health and Aging Study I) including 131 frail who participated in a test of EC. EC (seated step test), cardiac function (chronotropic index), pulmonary function (forced vital capacity, FVC), musculoskeletal function (quadriceps strength, QS), and frailty status were measured and interactive effects were modeled using linear regression and differentiation.ResultsEach physiological system had a direct relationship with EC, which was lower in frail compared with nonfrail. The relationship between FVC and EC was positive and increased with increasing QS in nonfrail subjects. The effect of QS on EC was positive and increased with increasing FVC regardless of frailty. In subjects with low QS, frailty status was associated with lower EC and this effect became stronger with increasing FVC.DiscussionFindings suggest but do not show that frailty status modifies the effects of physiological function in several systems on EC. Approaches to understanding emergent properties such as vulnerability to illness and death and clinical efforts to prevent and treat frailty should evaluate and possibly intervene on several physiological systems to be maximally effective.
AB - BackgroundA decline in exercise capacity (EC) is a characteristic of frailty. We hypothesized that decline is the effect of decrements in several physiological systems. We assessed whether the relationship of three main physiological systems-cardiac, pulmonary, and musculoskeletal-to EC is independent or interactive and whether their effect on EC varies with respect to frailty status.MethodsObservational study of 547 disabled women aged 65 years and older (Women's Health and Aging Study I) including 131 frail who participated in a test of EC. EC (seated step test), cardiac function (chronotropic index), pulmonary function (forced vital capacity, FVC), musculoskeletal function (quadriceps strength, QS), and frailty status were measured and interactive effects were modeled using linear regression and differentiation.ResultsEach physiological system had a direct relationship with EC, which was lower in frail compared with nonfrail. The relationship between FVC and EC was positive and increased with increasing QS in nonfrail subjects. The effect of QS on EC was positive and increased with increasing FVC regardless of frailty. In subjects with low QS, frailty status was associated with lower EC and this effect became stronger with increasing FVC.DiscussionFindings suggest but do not show that frailty status modifies the effects of physiological function in several systems on EC. Approaches to understanding emergent properties such as vulnerability to illness and death and clinical efforts to prevent and treat frailty should evaluate and possibly intervene on several physiological systems to be maximally effective.
KW - Exercise capacity
KW - Frailty
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U2 - 10.1093/gerona/glp147
DO - 10.1093/gerona/glp147
M3 - Article
C2 - 19822621
AN - SCOPUS:77949493848
SN - 1079-5006
VL - 65 A
SP - 287
EP - 294
JO - Journals of Gerontology - Series A Biological Sciences and Medical Sciences
JF - Journals of Gerontology - Series A Biological Sciences and Medical Sciences
IS - 3
ER -