Disability and effects of weight loss in obese women

Abstract

INTRODUCTION: Obesity has become an important health problem world wide. It increases medical risks and affects daily living. Women are in the majority among obese persons seeking help. Standard recommendations on fitness training and losing weight by walking are common. Physiotherapists know little about disability problems in obese women and we lack obesity-specific instruments for outcome evaluation.

OBJECTIVES: The overall aim of the present thesis was to identify and describe physical disability in obese women and to evaluate the impact of dieted weight loss on disability.

METHODS: Fifty-seven obese female outpatients, mean age 44 years and mean body mass index 37 kg.m-2 were consecutively selected. All measurements were taken before and after 12 weeks of dieting and after a 52-week weight maintenance period. A walking test entailed measured walking speed and oxygen consumption (VO2), heart rate (HR), perceived exertion and pain. Maximum oxygen uptake (VO2max/kg) was predicted. Current musculoskeletal pain was assessed. To reach our goal we had to design two new instruments, an Obesity Questionnaire for assessing perceived disability regarding self-care, mobility, household tasks, work and community, social and civic life and a Functional Test for observing activity limitations - with activities measuring mobility and self-care. Data from 22 normal-weight women volunteers were used for comparisons.

RESULTS: In general, the two new instruments showed good validity and reliability. They could discriminate between obese and normal-weight women and in several parts they also showed sensitivity to changes. Many obese women had walking difficulties. They walked slowly and despite the self-selected speed many perceived pain and/or exertion during a five-minute indoor walking test. The relative oxygen cost of walking, %VO2max, was high, due to very low VO2max/kg. The obese women experienced musculoskeletal pain and, for them, activities of daily life implied a great many problems, much more than for women with normal weight. The Obesity Questionnaire threw light upon perceived problems with strenuous work, sports activities, urinary stress incontinence and housework. All activities requiring extra weight on the lower extremities - such as rising from sofas, climbing, stepping up, walking up stairs, squatting, stooping and lifting felt problematic - as did pedicure. Observation confirmed these enumerated difficulties. Moreover, the Functional Test revealed pain and exertion, slow pace and high HR in performing the selected activities. A moderate weight loss of 10% after the maintenance year improved walking ability in all aspects. Perceived and observed disability both improved markedly. A partial weight relapse during the maintenance period had some negative impact on pain and perceived problems but all improvements concerning activity limitations were long-lasting.

CONCLUSIONS: Very low V02max/kg causing high %VO2max during walking meant hard work and might explain why many obese women cannot exercise through long and brisk walks. The women studied suffered musculoskeletal pain and disability and revealed activity limitations in everyday life much more than women of normal weight do. A 10% weight reduction decreased pain and improved walking ability. It had positive effects on perceived disability and observed activity limitations. The Obesity Questionnaire and the Functional Test should be revised before further clinical use.

CLINICAL RELEVANCE AND RECOMMENDATIONS: When dealing with obese women it seems of great importance to improve VO2max/kg. A timed walk in the corridor with measures of FIR, pain and exertion might be a quick and simple clinical test to evaluate VO2max/kg and tolerance to weight-bearing activities. Advice on training should be individual and consideration given to body mass index, age and current lower-body pain. Attention should be drawn to positive weight loss effects on pain, walking ability and activities of daily living. As perceived disability may differ from observed, we need to measure both so as to allow goal-setting and evaluation of intervention outcomes.