Kay L. Cox

Effect of Physical Activity on Cognitive Function in Older Adults at Risk for Alzheimer Disease: A Randomized Trial

CONTEXT Many observational studies have shown that physical activity reduces the risk of cognitive decline; however, evidence from randomized trials is lacking. OBJECTIVE To determine whether physical activity reduces the rate of cognitive decline among older adults at risk. DESIGN AND SETTING Randomized controlled trial of a 24-week physical activity intervention conducted between 2004 and 2007 in metropolitan Perth, Western Australia. Assessors of cognitive function were blinded to group membership. PARTICIPANTS We recruited volunteers who reported memory problems but did not meet criteria for dementia. Three hundred eleven individuals aged 50 years or older were screened for eligibility, 89 were not eligible, and 52 refused to participate. A total of 170 participants were randomized and 138 participants completed the 18-month assessment. INTERVENTION Participants were randomly allocated to an education and usual care group or to a 24-week home-based program of physical activity. MAIN OUTCOME MEASURE Change in Alzheimer Disease Assessment Scale-Cognitive Subscale (ADAS-Cog) scores (possible range, 0-70) over 18 months. RESULTS In an intent-to-treat analysis, participants in the intervention group improved 0.26 points (95% confidence interval, -0.89 to 0.54) and those in the usual care group deteriorated 1.04 points (95% confidence interval, 0.32 to 1.82) on the ADAS-Cog at the end of the intervention. The absolute difference of the outcome measure between the intervention and control groups was -1.3 points (95% confidence interval,-2.38 to -0.22) at the end of the intervention. At 18 months, participants in the intervention group improved 0.73 points (95% confidence interval, -1.27 to 0.03) on the ADAS-Cog, and those in the usual care group improved 0.04 points (95% confidence interval, -0.46 to 0.88). Word list delayed recall and Clinical Dementia Rating sum of boxes improved modestly as well, whereas word list total immediate recall, digit symbol coding, verbal fluency, Beck depression score, and Medical Outcomes 36-Item Short-Form physical and mental component summaries did not change significantly. CONCLUSIONS In this study of adults with subjective memory impairment, a 6-month program of physical activity provided a modest improvement in cognition over an 18-month follow-up period. TRIAL REGISTRATION anzctr.org.au Identifier: ACTRN12605000136606.

The influence of exercise on brain aging and dementia

Physical activity has been recognized as an important protective factor reducing disability and mortality and therefore it is focus of many health promotion activities at all ages. More recently a growing body of literature is focusing whether physical activity could also have a positive impact on brain aging with exploring healthy brain aging as well as on cognitive impairment and dementia. An increasing number of prospective studies and randomized controlled trials involving humans take place both with older adults with normal cognition as well as with mild cognitive impairment or dementia. However, the body of evidence is still sparse and many methodological issues make comparisons across studies challenging. Increasingly research into underlying mechanisms in relation to physical activity and brain aging identify biomarker candidates with especially neuroimaging measurements being more used in trials with humans. Whilst the evidence base is slowly growing more detailed research is needed to address methodological issues to finally achieve clinical relevance. This article is part of a Special Issue entitled: Imaging Brain Aging and Neurodegenerative disease.

Exercise and weight control in sedentary overweight men: effects on clinic and ambulatory blood pressure.

Objective To examine whether restriction of caloric intake and exercise of vigorous intensity can independently and additively influence clinic and ambulatory blood pressures in sedentary overweight men. Design Sixty subjects aged 20-50 years were randomly allocated either to continue their normal caloric intake or to restrict it by 4186-6279 kJ/day, with 15% provided by protein, 30% by fat and 55% by carbohydrate, for 16 weeks. Within each of these groups subjects were further randomly allocated either to a control light intensity programme of exercise or to a vigorous intensity programme of exercise for 30min three times a week. The light exercise group performed stationary cycling against no resistance, flexibility exercises and slow walking, The vigorous intensity group cycled on an ergometer at 60-70% of maximum their workload. Results Fifty-one subjects completed the study. Their maximal oxygen uptake was increased by approximately 24% with vigorous exercise but did not change with light exercise. Caloric intake restriction led to a significant loss of body mass of 9.5 kg (95% confidence interval 7.6-11.3), whereas vigorous exercise had no effect Restriction of caloric intake reduced supine clinic systolic and diastolic blood pressures significantly by 5.6 (2.3-8.9) and 2.4 mmHg (0.4-4.2), respectively. Relative to the control light exercise group, exercise of vigorous intensity exercise had no significant effect on clinic blood pressure. In contrast, time series analysis revealed that both caloric intake restriction and vigorous exercise were associated with lower daytime ambulatory systolic blood pressure, the reduction in systolic blood pressure being sustained throughout the 24h period when vigorous exercise and caloric intake restriction were combined. Conclusion Compared with the effects of caloric intake restriction, the effects of a vigorous exercise programme on blood pressure are inconsistent, there being no influence on clinic blood pressure but a reduction in daytime ambulatory blood pressure. However, when combined with caloric intake restriction, regular vigorous exercise exhibits a synergistic effect in reducing ambulatory blood pressure throughout a 24h period.

Physical activity and mild cognitive impairment and Alzheimer's disease.

Regular physical activity undoubtedly has many health benefits for all age groups. In the past decade, researchers and clinicians have begun to focus their attention on whether physical activity also can improve health outcomes of older adults who experience mild cognitive impairment (MCI) or dementia. This ongoing question is gaining relevance in light of the aging of the world population and with it the rise of age-related conditions, such as cognitive impairment. Not surprisingly, physical activity is among the potential protective lifestyle factors mentioned when strategies to delay or prevent dementia are discussed. The first large-scale multidomain intervention trials are under way to put this to the test. This review aims to give an overview of recent trials of physical activity in patients with MCI or dementia.

Blood pressure rise with swimming versus walking in older women: the Sedentary Women Exercise Adherence Trial 2 (SWEAT 2).

Objective Swimming is often recommended in the prevention and treatment of hypertension. Few studies have investigated the effect of swimming training on blood pressure (BP). Our objective was to evaluate 6 months of supervised moderate swimming or walking on BP in previously sedentary, normotensive, older women. Design Women aged 50–70 years (n = 116) were randomly assigned to a supervised 6-month swimming or walking programme. They were further randomized to receive usual care or a behavioural intervention package. Methods Exercise comprised 3 sessions/week with a warm-up, cool down, and 30-min of moderate intensity walking or swimming. BP was recorded for 20 min supine, and 5 min standing. Assessments were made at 0 and 6 months. Results At baseline, mean supine BP (± SD) was 115.7 ± 1.3/66.8 ± 0.7 mmHg. Swimming improved swim distance by 78.1 m (29.3%) [95% confidence interval (CI); 66.7, 89.4] and walk time by 0.58 min (3.8%) (0.41, 0.74). Walking decreased walk time by 1.0 min (6.5%) (0.81, 1.19). After adjustment for initial BP, age, hypertension treatment status and change in weight, swimming increased supine and standing systolic BP relative to walking by 4.4 mmHg (1.2, 7.5) (P = 0.008) and 6.0 mmHg (2.6, 9.5) (P = 0.001), respectively. Supine and standing diastolic BP increased by 1.4 mmHg (−0.14, 3.0) (P = 0.07) and 1.8 mmHg (−0.02, 3.5) (P = 0.05), respectively. Conclusion Relative to moderately paced walking, regular swimming significantly elevates BP in previously sedentary, normotensive, older women. This finding may have important implications for exercise prescription in older subjects.

Long-term effects of exercise on blood pressure and lipids in healthy women aged 40-65 years: The Sedentary Women Exercise Adherence Trial (SWEAT)

Objectives To evaluate the long-term effects of regular moderate or vigorous intensity exercise on blood pressure and blood lipids in previously sedentary older women. Design Subjects were randomly assigned to either a supervised centre-based (CB) or a minimally supervised home-based (HB) exercise program, initially for 6 months. Within each program, subjects were further randomized to exercise either at moderate (40–55% heart rate reserve, HRres) or vigorous intensity (65–80% HRres). After 6 months, all groups continued a HB moderate or vigorous exercise program for another 12 months. Methods Healthy, sedentary women (aged 40–65 years) (n = 126) were recruited from the community. Subjects exercised three times per week for 30 min. They were evaluated at baseline, 6, 12 and 18 months. Results There was a significant fall of 2.81 mmHg in systolic blood pressure (P = 0.049) and 2.70 mmHg in diastolic blood pressure (P = 0.004) after correction for age and baseline values with moderate exercise, but not with vigorous-intensity exercise. When this analysis was repeated with the change in body mass included, the results were unchanged. After correction for potential confounding factors, there was a significant fall in total cholesterol and low density lipoprotein cholesterol with vigorous but not moderate exercise at 6 months (P < 0.05) but not at 18 months. Conclusions In this largely normotensive population of older women, a moderate, but not vigorous exercise program, achieved sustained falls in resting systolic and diastolic blood pressure over 18 months. The study demonstrates that, in older women, moderate intensity exercise is well accepted, sustainable long-term and has the health benefit of reduced blood pressure.

The combined effects of aerobic exercise and alcohol restriction on blood pressure and serum lipids : a two-way factorial study in sedentary men

Objectives To determine whether vigorous exercise and alcohol restriction have additive and independent effects in reducing blood pressure in sedentary male alcohol drinkers. Also to assess whether 4 weeks of vigorous exercise could offset the fall in high-density lipoprotein cholesterol (HDL-cholesteroI) usually observed after alcohol restriction. Design Seventy-five sedentary men were randomly assigned to drink low-alcohol beer or continue their normal drinking habits. Within these two groups subjects were further assigned either to a vigorous exercise programme of three 30-min sessions a week of cycling at 60-70% of maximum workload or to a control light-exercise programme. Results Seventy-two subjects completed the trial. Alcohol consumption fell by 85% in the low-alcohol group. Fitness increased by 10% following vigorous exercise, with a significant improvement in maximum oxygen uptake. After adjustment for weight loss, a significant effect of alcohol restriction in reducing both systolic and diastolic blood pressure was demonstrated. There was no effect of vigorous exercise on blood pressure. Serum total cholesterol, low-density lipoprotein cholesterol and apolipoprotein B were not influenced by alcohol restriction or vigorous exercise. However, alcohol restriction significantly reduced triglyceride, HDL-cholesteroI, its subfractions HDL2-cholesterol and HDL3-cholesterol, and its major apolipoproteins apo A-l and apo A-ll. These reductions were unaffected by moderate exercise. Conclusions This study provides further evidence that alcohol restriction results in reductions in blood pressure in men who are regular alcohol drinkers. However, a simultaneous increase in fitness did not lead to lower blood pressures than those achieved with alcohol restriction alone, and was unable to offset alcohol-related falls in HDL-cholesteroI, its subfractions and its major apolipoproteins.

Short and long-term adherence to swimming and walking programs in older women - The Sedentary Women Exercise Adherence Trial (SWEAT 2)

OBJECTIVE To examine in previously sedentary older women the effects of exercise mode and a behavioural intervention on short and long-term retention and adherence. METHODS Healthy, sedentary women aged 50-70 years (N=116) were randomly assigned to a supervised 6-month swimming or walking program 3 sessions a week. They were further randomised to usual care or a behavioural intervention. The same program was further continued unsupervised for 6 months. We assessed retention, adherence, stage of exercise behaviour and changes in fitness. RESULTS One hundred women (86%) completed 6 months and 86 (74%) continued for 12 months. Retention rates were similar for both exercise modes at 6 and 12 months. Adherence to swimming or walking was similar after 6 months (76.3 (95% CI: 69.5, 83.1)% vs. 74.3 (67.7, 80.9)%) and 12 months (65.8 (57.9, 73.8)% vs. 62.2 (54.6, 70.0)%). The behavioural intervention did not enhance retention or adherence. Fitness improved for both exercise modes after 6 months and was maintained at 12 months. CONCLUSIONS Either swimming or walking programs initiated with careful supervision over 6 months resulted in similar high retention and adherence rates by highly motivated older women over 12 months. Behavioural intervention in this setting did not improve these rates further.

Protocol for a randomized controlled trial evaluating the effect of physical activity on delaying the progression of white matter changes on MRI in older adults with memory complaints and mild cognitive impairment: The AIBL Active trial

BackgroundOlder adults free of dementia but with subjective memory complaints (SMC) or mild cognitive impairment (MCI) are considered at increased risk of cognitive decline. Vascular risk factors (VRF), including hypertension, heart disease, smoking, hypercholesterolemia and lack of physical activity (PA) have been identified as modifiable risk factors contributing to cognitive decline, and white matter hyperintensities (WMH) are associated with VRF, SMC and cognitive impairment. Findings from a growing number of clinical trials with older adults are providing strong evidence for the benefits of physical activity for maintaining cognitive function, but few studies are investigating these benefits in high-risk populations. The aim of AIBL Active is to determine whether a 24-month physical activity program can delay the progression of white matter changes on magnetic resonance imaging (MRI).Methods/designThis single-blind randomized controlled trial (RCT) is offered to 156 participants, aged 60 and older, in the Melbourne arm of the Australian Imaging Biomarkers and Lifestyle Flagship Study of Aging (AIBL). Participants must have SMC with or without MCI and at least one VRF. The PA intervention is a modification of the intervention previously trialed in older adults with SMC and MCI (Fitness for the Ageing Brain Study). It comprises 24 months of moderate, home-based PA (150 minutes per week) and a behavioral intervention package. The primary outcome measure will be change in WMH after 24 months on MRI. Cognition, quality of life, functional fitness, level of physical activity, plasma biomarkers for cerebrovascular disease and amyloid positron emission tomography (PET) imaging comprise secondary measures.DiscussionCurrently, there is no effective pharmacological treatment available to delay cognitive decline and dementia in older adults at risk. Should our findings show that physical activity can slow down the progression of WMH, this RCT would provide an important proof of concept. Since imbedded in AIBL this RCT will also be able to investigate the interaction between vascular and Alzheimers disease pathologies.Trial RegistrationAustralia New Zealand Clinical Trials Registry ACTRN12611000612910

A comparison of the effects of swimming and walking on body weight, fat distribution, lipids, glucose, and insulin in older women--the Sedentary Women Exercise Adherence Trial 2.

All types of aerobic exercise are assumed to affect cardiovascular risk similarly. There are few studies of swimming, but complex responses to water-based exercise suggest its potential for differential effects. The aim of the study was to compare the effects of swimming and walking on fitness, body weight, lipids, glucose, and insulin in older women. Sedentary women aged 50 to 70 years (N = 116), randomly assigned to swimming or walking plus usual care or a behavioral intervention, completed 3 sessions per week of moderate-intensity exercise, supervised for 6 months then unsupervised for 6 months. After 6 months, 1.6-km walk time decreased in walkers and swimmers, with greater improvement in walkers (1.0 vs 0.6 minute, P = .001). In swimmers, but not walkers, distance swum in 12 minutes increased (78.1 vs -2.2 m, P = .021). Waist and hip circumferences (80.8 vs 83.1 cm and 101.8 vs 102.4 cm; P = .023 and P = .042, respectively) and insulin area under the curve (oral glucose tolerance test) (5128 vs 5623 μU/[L 120 min], P < .05) were lower with swimming. Lipids did not differ between groups. At 12 months, fitness was maintained. Relative to walking, swimming reduced body weight by (1.1 kg, P = .039) and resulted in lower total and low-density lipoprotein cholesterol (0.3 and 0.2 mmol/L; P = .040 and P = .049, respectively). The magnitude of the difference in the reduction of insulin area under the curve between swimming and walking was greater at 12 months; however, the significance was attenuated (4677 vs 5240 μU/[L 120 min], P = .052). Compared with walking, swimming improved body weight, body fat distribution, and insulin in the short term and, in the longer term, body weight and lipid measures. These findings suggest that the type of exercise can influence health benefits.