Low-dose Exercise Research Articles

Aerobic exercise enhances executive function and academic achievement in sedentary, overweight children aged 7–11 years

Summary of: Davis CL et al (2011) Exercise improves executive function and achievement and alters brain activation in overweight children: a randomized controlled trial. Health Pscyh 30: 91-98. [Prepared by Nora Shields, CAP Editor.] Does aerobic exercise improve cognition and academic achievement in overweight children aged 7-11 years? Randomised, controlled trial with concealed allocation and blinded outcome assessment. After school program in the United States. Overweight, inactive children aged 7-11 years with no medical contraindication to exercise. Randomisation of 171 participants allocated 56 to a high dose exercise group, 55 to a low dose exercise group, and 60 to a control group. Both exercise groups were transported to an after school exercise program each school day and participated in aerobic activities including running games, jump rope, and modified basketball and soccer. The emphasis was on intensity, enjoyment, and safety, not competition or skill enhancement. The student-instructor ratio was 9:1. Heart rate monitors were used to observe the exercise intensity. Points were awarded for maintaining an average of>150 beats per minute and could be redeemed for weekly prizes. The high dose exercise group received 40 min/day aerobic exercise and the low dose exercise group received 20 min/day aerobic exercise and 20 min/day unsupervised sedentary activities including board games, drawing, and card games. The average duration of the program was 13 ± 1.6 weeks. The control group did not receive any after school program or transportation. The primary outcome was the Cognitive Assessment System taken at baseline and postintervention. This measure tests four cognitive processes: planning (or executive function), attention, simultaneous, and successive tasks with each process yielding a standard score with a mean of 100 and a SD of 15. Secondary outcome measures were the broad reading and mathematics clusters of the Woodcock-Johnson Tests of Achievement III. 164 participants completed the study. At the end of the intervention period, there was a dose-response benefit of exercise on executive function (linear trend p=0.013) and mathematics achievement (linear trend p=0.045); ie, the post-intervention group scores for these outcomes increased with the intensity of exercise. Compared to the control group, exposure to either exercise program resulted in higher executive function scores (mean difference=-2.8, 95% CI -5.3 to -0.2 points) but not in higher mathematics achievement scores. The groups did not differ significantly on any of the other outcomes. There were no differences between the two exercise groups. Aerobic exercise enhances executive function in overweight children. Executive function develops in childhood and is important for adaptive behaviour and cognitive development.

Dose–response effects of graded therapeutic exercises in patients with long-standing subacromial pain

Exercise therapy is widely used in the conservative treatment of long-standing subacromial pain, but there is still no consensus on recommending any specific treatment schedules. The aim of this study was to examine the effect of a high-dose versus a low-dose of the same repetitive exercise program in patients with long-standing subacromial pain/impingement. Sixty-one patients were randomly assigned either to a high-dose medical exercise therapy group (HD) (n=31) or to the low-dose exercise therapy group (LD) (n=30). The study was a randomized controlled trial. Both groups received three treatments a week over a 3-month period. The differences between the groups were: number of repetitions, number of sets and time spent on performing global aerobic exercises. Patients in both the LD group and HD group experienced improvements in functional ability, and the HD group had significant better results compared with the LD group with respect to pain, function, range of motion and isometric strength. However, bot...

Aerobic Exercise and Snoring in Overweight Children: A Randomized Controlled Trial

To determine whether regular aerobic exercise improves symptoms of sleep-disordered breathing in overweight children, as has been shown in adults. Healthy but overweight (BMI > or =85th percentile) 7- to 11-year-old children were recruited from public schools for a randomized controlled trial of exercise effects on diabetes risk. One hundred children (53% black, 41% male) were randomly assigned to a control group (n = 27), a low-dose exercise group (n = 36), or a high-dose exercise group (n = 37). Exercise groups underwent a 13 +/- 1.5 week after-school program that provided 20 or 40 minutes per day of aerobic exercise (average heart rate = 164 beats per minute). Group changes were compared on BMI z-score and four Pediatric Sleep Questionnaire scales: Snoring, Sleepiness, Behavior, and a summary scale, Sleep-Related Breathing Disorders. Analyses were adjusted for age. Both the high-dose and low-dose exercise groups improved more than the control group on the Snoring scale. The high-dose exercise group improved more than the low-dose exercise and control groups on the summary scale. No group differences were found for changes on Sleepiness, Behavior, or BMI z-score. At baseline, 25% screened positive for sleep-disordered breathing; half improved to a negative screen after intervention. Regular vigorous exercise can improve snoring, a symptom of sleep-disordered breathing, in overweight children. Aerobic exercise programs may be valuable for prevention and treatment of sleep-disordered breathing in overweight children.

Low-dose exercise training does not influence cardiac autonomic control in healthy sedentary men aged 55 – 75 years

The purpose of this study was to evaluate the effects of a realistic, feasible, and commonly used fitness training programme on cardiac autonomic control in 14 sedentary men aged 62.0 ± 6.1 years (mean ± s). All participants performed a one-year fitness training programme in which training intensity and frequency were specifically chosen to be compliant for the majority of the participants (2 – 3 sessions per week at moderate intensity). At the same time, a reference group consisting of 15 sedentary age-matched men (age 64.2 ± 6.5 years) did not change their habitual physical activity. Measurements were performed before and after the training intervention. Cardiac autonomic control was inferred from resting values (supine and standing) of heart rate variability (HRV) computed in the frequency domain over 10-min intervals. Endurance capacity was evaluated during a maximal incremental bicycle ergometer test. In spite of an increase in peak oxygen consumption ([Vdot]O2peak) by 6.4% after training, heart rate in the training group remained unchanged at rest and at the same metabolic demand. No changes in resting parameters of HRV were shown for either groups or positions. Results from this study provide no evidence of a clinically meaningful increase in the vagal modulation to the sinus node at rest after one year of low-volume and moderate-intensity fitness training in men aged 55 – 75 years.

Systematic Review: Strategies for Using Exercise Therapy To Improve Outcomes in Chronic Low Back Pain

Exercise therapy encompasses a heterogeneous group of interventions. There continues to be uncertainty about the most effective exercise approach in chronic low back pain. To identify particular exercise intervention characteristics that decrease pain and improve function in adults with nonspecific chronic low back pain. MEDLINE, EMBASE, PsychInfo, CINAHL, and Cochrane Library databases to October 2004 and citation searches and bibliographic reviews of previous systematic reviews. Randomized, controlled trials evaluating exercise therapy in populations with chronic (>12 weeks duration) low back pain. Two reviewers independently extracted data on exercise intervention characteristics: program design (individually designed or standard program), delivery type (independent home exercises, group, or individual supervision), dose or intensity (hours of intervention time), and inclusion of additional conservative interventions. 43 trials of 72 exercise treatment and 31 comparison groups were included. Bayesian multivariable random-effects meta-regression found improved pain scores for individually designed programs (5.4 points [95% credible interval (CrI), 1.3 to 9.5 points]), supervised home exercise (6.1 points [CrI, -0.2 to 12.4 points]), group (4.8 points [CrI, 0.2 to 9.4 points]), and individually supervised programs (5.9 points [CrI, 2.1 to 9.8 points]) compared with home exercises only. High-dose exercise programs fared better than low-dose exercise programs (1.8 points [CrI, -2.1 to 5.5 points]). Interventions that included additional conservative care were better (5.1 points [CrI, 1.8 to 8.4 points]). A model including these most effective intervention characteristics would be expected to demonstrate important improvement in pain (18.1 points [CrI, 11.1 to 25.0 points] compared with no treatment and 13.0 points [CrI, 6.0 to 19.9 points] compared with other conservative treatment) and small improvement in function (5.5 points [CrI, 0.5 to 10.5 points] compared with no treatment and 2.7 points [CrI, -1.7 to 7.1 points] compared with other conservative treatment). Stretching and strengthening demonstrated the largest improvement over comparisons. Limitations of the literature, including low-quality studies with heterogeneous outcome measures and inconsistent and poor reporting; publication bias. Exercise therapy that consists of individually designed programs, including stretching or strengthening, and is delivered with supervision may improve pain and function in chronic nonspecific low back pain. Strategies should be used to encourage adherence. Future studies should test this multivariable model and further assess specific patient-level characteristics and exercise types.

EFFECT OF EXERCISE TRAINING DOSE AND INTENSITY ON LIPOPROTEINS AND LIPOPROTEIN SUBFRACTIONS

Increased levels of physical activity are clearly related to reduced risk of CVD. One possible mechanism is through improvements in lipoproteins. However, the optimal exercise stimulus is unknown as there are no dose-response studies. PURPOSE: We investigated the effects of training dose and intensity on lipoproteins and their subfractions. METHODS: Eightyfour males and females, aged 40–65, who were overweight/obese (BMI 25–35 kg/m2) with dyslipidemia (LDL-C: 130–190 OR HDL-C < 40) were randomized to a control or one of three exercise groups: low dose/moderate intensity (12 miles/wk at 50% peak VO2), low dose/vigorous intensity (12 miles/wk at 75%), high dose/vigorous intensity (20 miles/wk at 75%). Training included a 2–3 month ramp period plus 6 months of exercise at the assigned intensity/dose. RESULTS: Exercise did not effect total or LDL-C. High dose exercise significantly (P < 0.05) decreased small LDL's, LDL particle concentration, average LDL size, triglycerides, and total VLDL-TG and increased large HDL's, average HDL size, and total HDL's, with a tendency (P < 0.06) for reduced large VLDL's compared to controls. Low dose exercise was less beneficial. The high dose-vigorous group had a larger improvement than low dose-vigorous on 10 of 11 variables and the low dose had a better effect than the control on all 11 variables - clear evidence of a dose-response effect. CONCLUSION: The data show that, for individuals with mild to moderate dyslipidemia, high dose exercise has widespread beneficial effects on lipoproteins. However, few of these benefits would be detected by a typical lipid panel. The data also demonstrate a clear dose-response effect. The effects of exercise intensity appear to be much less important than exercise dose.