The Effects of High-intensity Aerobic Training in Patients With Metabolic Syndrome

The Effects of High-intensity Aerobic Training in Patients With Metabolic Syndrome and Its Dose Response Study

Background. The prevalence of metabolic syndrome (MetS) has been increasing, and its risk is positively correlated with age. Due to ageing society in Taiwan, how to treat metabolic syndrome and decrease the complications is an important health issue. Relatively few studies have been focusing on the effects of exercise training in patients with MetS with long-term follow-up. Recently, high-intensity interval training or aerobic interval training (AIT) consisting of high intensity separated by active recovery has been proposed to be more effective than isocaloric continuous moderate-intensity exercise (CME) in raising exercise capacity (VO2max) in some specific patient population. Purpose. The purposes are to (1) compare the effects of 16-week CME and AIT on reducing the numbers of metabolic risk factors in patients with MetS and the prevalence. Hypothesis: 16-week AIT reduces more metabolic risk factors than CME in patients with MetS. Methods. This study will be a multiple-center trial. One hundred and twenty patients, aged ≥45 years, with a diagnosis of MetS for each center will be recruited. Subjects will be randomly assigned to either control, CME, or AIT group after baseline assessments. Participants in control group will receive usual care and the others in two exercise groups will undergo 16-week exercise training. All subjects will receive 16-week, 6-month and 1-year follow-ups including blood test, body composition (body mass index, waist circumference), pulse wave velocity, and maximal exercise testing. Statistical analysis will be conducted using SPSS 11.5, p < 0.05 indicating statistical significance. Data will be presented in mean±standard deviation or number (percentile) with intention-to-treat analysis. Chi-square test or one-way Analysis of Variance (ANOVA) will be used to compare whether there are between-group differences at baseline. Two-way repeated measures ANOVA and post-hoc test will be performed to examine time and group effect if there is interaction effect, otherwise Bonferroni will be used. The subgroup analysis between MetS and n-MetS after training will be performed using the same statistical methods.

Intervention (exercise) protocol: CME group: exercise at least 30-minute moderate intensity 5 times a week, twice on treadmill under supervision and home exercise 3 times a week. CME protocol including 10-minute warm-up at 40% maximal heart rate (HRmax), 30-minute moderate intensity exercise at 50-70% HRmax and 5-minute cool-down at 40% HRmax AIT group: exercise 3 times a week including twice on treadmill under supervision and home exercise once a week. AIT protocol including 10-minute warm-up and 5-minute cool-down at 40% HRmax, participants and exercise 4-minute high-intensity training at 85-90% HRmax and 4 times separated by 3-minute active recovery at 70% HRmax.

Metabolic syndrome, Metabolic risk factors, High-intensity interval training, Moderate-intensity exercise

Frequency: Exercise 3 times a week. Twice under supervision and home exercise once a week. Duration: Totally 40 minutes in one session. Intensity: 10-minute warm-up and 5-minute cool-down at 40% maximal heart rate (HRmax), participants and exercise 4-minute high-intensity training at 85-90% HRmax and 4 times separated by 3-minute active recovery at 70% HRmax. Type: Using treadmill while under supervision.

Frequency: 5 times a week. Twice under supervision and home exercise 3 times a week. Duration: Totally 45 minutes per session. Intensity: 10-minute warm-up at 40% maximal heart rate (HRmax), 30-minute moderate intensity exercise at 50-70% HRmax and 5-minute cool-down at 40% HRmax Type: Using treadmill under supervision.

Using exercise testing to evaluate peak oxygen consumption at peak exercise to know the cardiopulmonary fitness in all subjects.

Assessing continuous heart rate at resting (10-min), during exercise testing, and after exercise testing (10-min) and further analyzing heart rate variability in time and frequency domain.

Assessing blood pressure in four limbs to analyze pulse wave velocity and evaluate the stiffness of peripheral arteries.

Using exercise testing to evaluate peak oxygen consumption at peak exercise to know the cardiopulmonary fitness in all subjects.

Using exercise testing to evaluate peak oxygen consumption at peak exercise to know the cardiopulmonary fitness in all subjects.

Assessing continuous heart rate at resting (10-min), during exercise testing, and after exercise testing (10-min) and further analyzing heart rate variability in time and frequency domain.

Assessing continuous heart rate at resting (10-min), during exercise testing, and after exercise testing (10-min) and further analyzing heart rate variability in time and frequency domain.

Assessing blood pressure in four limbs to analyze pulse wave velocity and evaluate the stiffness of peripheral arteries.

Assessing blood pressure in four limbs to analyze pulse wave velocity and evaluate the stiffness of peripheral arteries.

Inclusion Criteria: 45-75 years old diagnosis of metabolic syndrome able to follow the instruction Exclusion Criteria: unstable hypertension coronary artery disease or pulmonary diseases chronic kidney failure unable to perform exercise