To evaluate the evidence on the benefits of exercise in later life.

MEDLINE and Best Evidence were searched from 1985 to 2000 using the search terms 'exercise', 'physical activity', 'randomized controlled trials' and 'quasi experimental'. The search was limited to publications in the English language.

Study designs of evaluations included in the review

The inclusion criteria for study design were experimental and quasi-experimental studies. The review included randomised controlled trials (RCTs) and quasi-experimental studies.

Specific interventions included in the review

The inclusion criteria for the interventions were late-life exercise programmes. The exercise programmes included in the review fell into five categories: flexibility interventions including yoga and stretching; strengthening or resistence training; aerobic conditioning, e.g. aquatic programmes, low-impact aerobics, walking or cycling; balance programmes, e.g. t'ai chi or computerised balance systems; and combinations of programmes. The delivery of the programmes varied: some were delivered in the participants' homes or communities, while others were delivered in a supervised class format. Although there was much variation, the exercise sessions lasted 45 to 60 minutes and were performed two or three times per week. The duration of the interventions lasted from 2 to 18 months, with most lasting for 2 to 3 months. The follow-up ranged from immediate post-intervention to 9 months.

Participants included in the review

The inclusion criteria for the participants were elderly people aged greater than 60 years. The studies included some participants less than 60 years of age, but the mean age of the samples in all studies was over 60 years of age.

Outcomes assessed in the review

The inclusion criteria for the outcomes were measures of the following:

physical disability, using physical disability subscales of the Sickness Impact Profile (SIP), Short-Form-36 Health Sickness Survey (SF-36), the Arthritis Impact Measurement Scale, and other assessments of activities of daily living (ADLs) and/or instrumental ADLs such as the Barthel Index;

social disability, using the SF-36 social role subscale;

emotional disability, using instruments tapping depressive or anxiety symptoms and affect such as the Center for Epidemiological Studies- Depression Scale, the Geriatric Depression Scale, the SF-36 emotional subscale, the Philadelphia Geriatric Center Morale Scale, the Affect Balance Scale, the State-Trait Anxiety Inventory and the Profile of Moods; and

overall disability, using measures that captured summary scores of physical, social and emotion disability such as the SF-36 and SIP.

How were decisions on the relevance of primary studies made?

The authors do not state how the papers were selected for the review, or how many of the reviewers performed the selection.

The authors do not state that they assessed quality.

The authors do not state how the data were extracted for the review, or how many of the reviewers performed the data extraction. The data extracted included the type of intervention programme, length of intervention and follow-up assessment, sample size, and the intervention effect on impairment, function, and physical, emotional, social and overall disability.

How were the studies combined?

A narrative synthesis was undertaken. The review was structured around a hierarchy of outcomes using Nagi's disablement model, which has been widely used in the gerontological literature (see Other Publications of Related Interest nos.1-2). Effect sizes were reported for studies that reported significant effects for exercise on physical disability. The effect sizes for emotional, social and overall disability were not calculated because either few studies explored these outcomes (i.e. social and overall disability), or the outcomes measures used were inconsistent (i.e. emotional disability).

How were differences between studies investigated?

The authors do not state a method for assessing any differences between the studies.

Thirty-one studies were included in the review: 29 RCTs and 2 quasi-experimental trials.

Thirty-one studies were identified. Impairment and functional outcomes were reported in 97 and 81% of the studies, respectively; half of the studies examined disability outcomes. The most consistent positive effects of late-life exercise were observed in strength, aerobic capacity, flexibility, walking and standing balance, with over half of the studies that examined these outcomes finding positive effects. Of the studies that examined physical, social, emotional or overall disability outcomes, most found no improvements. In the five studies that reported reduced physical disability, the effect sizes ranged from 0.23 to 0.88.

Late-life exercise clearly improves strength, aerobic capacity, flexibility and physical function. However, existing scientific evidence does not support a strong argument for late-life exercise as an effective means of reducing disability. This may be due, in part, to methodological limitations in studies that have examined disability outcomes. On the other hand, the theoretical basis of interventions aimed at reducing disability may need to extend beyond exercise and address behavioural and social factors.

This review was methodologically weak. For example, many details of the review process were not reported, such as how the studies were selected for inclusion, how the data were extracted, and how many reviewers performed each stage of the review. Similarly, the literature search was weak: only English language papers were selected for inclusion, only two databases were searched for relevant studies, no handsearches or bibliography checks were reported, and there appears to have been no attempt to find unpublished material. Finally, there was no quality assessment of the studies that were included in the review. The results of the review should be interpreted with caution.

Practice: The authors did not state any implications for practice.

Research: The authors state that further research must address study design and methodological quality issues, and that the theoretical basis of programmes need to be addressed so that stronger, theoretically driven interventions may be developed and evaluated. More research is needed to examine the mediating and moderating role of beliefs, emotions, coping strategies, and physical and social environments so that interventions can be developed and evaluated to enhance behaviour and reduce late-life disability.

National Institute on Aging, grant numbers T-32 AG 00220 and AG 11669; National Institute on Disability and Rehabilitation Research, grant number H113B990005.

1. Nagi SZ. Some conceptual issues in disability and rehabilitation. In: Sussman MN, editor. Sociology and rehabilitation. Washington (DC): American Sociological Association; 1965. 2. Verbrugge LM, Jette AM. The disablement process. Soc Sci Med 1994;38:1-14.

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.