Physical activity and cardiovascular risk factors: effect of advice from an exercise specialist in Australian general practice.

OBJECTIVE: To determine whether provision of individualised physical activity advice by an exercise specialist in general practice is effective in modifying physical activity and cardiovascular risk factors in older adults. DESIGN: Randomised controlled trial of individualised physical activity advice, reinforced at three and six months (intervention) versus no advice (control). SETTING: Two general practices in Adelaide, South Australia, 1996. PARTICIPANTS: 299 adults aged 60 years or more who were healthy, sedentary and living in the community. MAIN OUTCOME MEASURES: Changes to physical activity (frequency and duration of walking and vigorous exercise), selected cardiovascular risk factors (blood pressure, body weight, serum lipid levels) and quality of life over 12 months. RESULTS: Self-reported physical activity increased over the 12 months in both groups (P < 0.001). The increase was greater for the intervention than the control group for all measures except time spent walking (P < 0.05). More intervention than control participants increased their intention to exercise (P < 0.001). Serum levels of total and low-density lipoprotein cholesterol and triglycerides fell significantly over the 12 months to a similar extent in the two groups. No other significant changes in cardiovascular risk factors were seen. Quality-of-life scores decreased over the 12 months. The decrease was significantly greater among intervention than control women, but not men, for emotional well-being (P = 0.02), physical well-being (P = 0.04) and social functioning (P = 0.04). DISCUSSION: Provision of general practice-based physical activity advice reinforced three-monthly produced a sustained increase in self-reported physical activity. However, there were no associated changes in clinical measures of cardiovascular risk factors and minimal changes in quality-of-life measures.

Exercise training and blood lipids in hyperlipidemic and normolipidemic adults: a meta-analysis of randomized, controlled trials.

OBJECTIVE: To determine the effectiveness of exercise training (aerobic and resistance) in modifying blood lipids, and to determine the most effective training programme with regard to duration, intensity and frequency for optimizing the blood lipid profile. DESIGN: Trials were identified by a systematic search of Medline, Embase, Science Citation Index (SCI), published reviews and the references of relevant trials. The inclusion criteria were limited to randomized, controlled trials of aerobic and resistance exercise training which were conducted over a minimum of four weeks and involved measurement of one or more of the following: total cholesterol (TC), high density lipoprotein (HIDL-C), low density lipoprotein (LDL-C) and triglycerides (TG). SUBJECTS: A total of 31 trials ( 1833 hyperlipidemic and normolipidemic participants) were included. RESULTS: Aerobic exercise training resulted in small but statistically significant decreases of 0.10 mmol/L (95% CI: 0.02, 0.18). 0.10 (95% CI: 0.02, 0.19), 0.08 mmol/L (95% CI: 0.02, 0.14), for TC, LDL-C, and TG, respectively, with an increase in HDL-C of 0.05 mmol/L (95% CI: 0.02, 0.08). Comparisons between the intensities of the aerobic exercise programmes produced inconsistent results; but more frequent exercise did not appear to result in greater improvements to the lipid profile than exercise three times per week. The evidence for the effect of resistance exercise training was inconclusive. CONCLUSIONS: Caution is required when drawing firm conclusions from this study given the significant heterogeneity with comparisons. However, the results appear to indicate that aerobic exercise training produced small but favourable modifications to blood lipids in previously sedentary adults.

Recruitment of older adults for a randomized, controlled trial of exercise advice in a general practice setting.

OBJECTIVES: The success of any clinical trial depends strongly on recruiting enough participants in a reasonable time period. This paper aims to identify the obstacles, as well as the successful aspects, of recruiting of older participants into an exercise study. DESIGN: This describes the recruitment of 299 older adults into a randomized, controlled trial of exercise advice in a general practice setting. Letters of invitation were sent from two general practices inviting the patients to attend a 15-minute screening appointment. Patients considered eligible for enrollment were then scheduled for a baseline appointment and randomized into the trial. SETTING: Two general practices in Adelaide, South Australia. PARTICIPANTS: Healthy, sedentary, community-dwelling patients aged 60 years or older. RESULTS: A total of 2878 letters of invitation were sent, and 913 patients attended a screening appointment. Of these, 351 (38.4%) were initially eligible, with one-third excluded because they were already too physically active. Two hundred ninety-nine participants, approximately 1 of every 10 patients sent letters, were enrolled in the project at the end of a 15-week period. DISCUSSION: A general practice approach was effective in recruiting 299 older adults to an exercise project within an acceptable time frame. Factors promoting the success of recruitment through general practice included choosing large, well established practices, computerized age-sex registers, and placing minimal demands on the general practitioners and practice staff. A continuing problem with recruiting participants for a project involving exercise is that the volunteer population tends to be healthy and interested in physical activity.

The effectiveness of exercise training in lowering blood pressure: a meta-analysis of randomised controlled trials of 4 weeks or longer.

OBJECTIVE: To identify the features of an optimal exercise programme in terms of type of exercise, intensity and frequency that would maximise the training induced decrease in blood pressure (BP). DATA IDENTIFICATION: Trials were identified by a systematic search of Medline, Embase and Science Citation Index (SCI), previous review articles and the references of relevant trials, from 1980 until 1996, including only English language studies. STUDY SELECTION: The inclusion criteria were limited to randomised controlled trials of aerobic or resistance exercise training conducted over a minimum of 4 weeks where systolic and diastolic BP was measured. RESULTS: A total of 29 studies (1533 hypertensive and normotensive participants) were included, 26 used aerobic exercise training, two trials used resistance training and one study had both resistance and aerobic training groups. Aerobic exercise training reduced systolic BP by 4.7 mm Hg (95% CI: 4.4, 5.0) and diastolic BP by 3.1 mm Hg (95% CI: 3.0, 3.3) as compared to a non-exercising control group, however, significant heterogeneity was observed between trials in the analysis. The BP reduction seen with aerobic exercise training was independent of the intensity of exercise and the number of exercise sessions per week. The evidence for the effect of resistance exercise training was inconclusive. CONCLUSIONS: Aerobic exercise training had a small but clinically significant effect in reducing systolic and diastolic BP. Increasing exercise intensity above 70% VO2 max or increasing exercise frequency to more than three sessions per week did not have any additional impact on reducing BP.

Exercise profile and subsequent mortality in an elderly Australian population.

Although the importance of exercise as a public health issue is increasingly recognised, little attention has been paid to exercise in very old people. We examined exercise patterns in 1788 subjects aged 70 years and over who were participating in the Australian Longitudinal Study of Ageing. In the two weeks before interview, 39 per cent of subjects had taken no exercise and only four per cent had exercised vigorously. When compared with those who took no exercise, exercisers were more likely to be male and younger, to self-report better health, to be former smokers and regular alcohol users. Mortality rates at two years follow-up were inversely related to the level of exercise at baseline. This research indicates that exercise is important for the very old as well as younger groups.

Effect of muscle glycogen availability on maximal exercise performance.

This investigation determined the influence of pre-exercise muscle glycogen availability on performance during high intensity exercise. Nine trained male cyclists were studied during 75 s of all-out exercise on an air-braked cycle ergometer following muscle glycogen-lowering exercise and consumption of diets (energy content approximately 14 MJ) that were either high (HCHO(80% CHO) or low (LCHO-25% CHO) in carbohydrate content. The exercise-diet regimen was successful in producing differences in pre-exercise muscle glycogen contents [HCHO: 578(SEM 55) mmol x kg(-1) dry mass; LCHO: 364 (SEM 58) P < 0.05 mmol x kg(-1) dry mass]. Despite this difference in muscle glycogen availability, there were no between trial differences for peak power [HCHO 1185 (SEM 50)W, LCHO 1179 (SEM 48)W], mean power [HCHO 547 (SEM 5)W, LCHO 554 (SEM 8)W] and maximal accumulated oxygen deficit [HCHO 54.4 (SEM 2.3) ml x kg(-1), LCHO 54.6 (SEM 2.0) ml x kg(-1)]. Postexercise muscle lactate contents (HCHO 95.9 (SEM 4.6) mmol x kg(-1) dry mass, LCHO 82.7 (SEM 12.3) mmol x kg(-1) dry mass, n = 8] were no different between the two trials, nor were venous blood lactate concentrations immediately after and during recovery from exercise. These results would indicate that increased muscle glycogen availability has no direct effect on performance during all-out high intensity exercise.