Effects of low-versus high-volume high-intensity interval training on glycemic control and quality of life in obese women with type 2 diabetes. A randomized controlled trial.

Background/objective: Comparison between different training volumes of high-intensity interval training (HIIT) is understudied in type 2 diabetes. This study aimed to compare the effects of low- and high-volume HIIT on glycemic control, blood lipids, blood pressure, anthropometric adiposity measures, cardiorespiratory fitness, and health-related quality of life (HRQoL) in women with type 2 diabetes. Methods: Seventy-two obese women with type 2 diabetes aged 36-55 were randomly assigned to a low-volume HIIT group (i.e., 2 × 4-min high-intensity treadmill exercise at 85%-90% of peak heart rate, with a 3-min active recovery interval in between), a high-volume HIIT group (i.e., 4 × 4-min high-intensity treadmill exercise at 85%-90% of peak heart rate, with three 3-min active recovery intervals in between), and a non-exercising control group. Patients in HIIT groups exercised three days a week for 12 weeks. All patients received oral hypoglycemic medications with no calorie restrictions. The outcome measures were glycosylated hemoglobin (HbA1c), fasting blood glucose (FBG), 2-hour postprandial blood glucose (2-hr PPBG), total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL), systolic blood pressure (SBP), diastolic blood pressure (DBP), body mass index (BMI), waist circumference (WC), waist-to-hip ratio, time to maximal exhaustion determined from a maximal treadmill exercise test (i.e., a measure of cardiorespiratory fitness), and HRQoL assessed by the 12-item Short Form (SF-12) Health Survey. Results: The low- and high-volume HIIT groups showed significant improvements in all outcome measures compared to the baseline and the non-exercising group (P < 0.05), except for DBP in the low-volume HIIT group (p > 0.05). Also, both low- and high-volume HIIT groups showed similar improvements in TC, HDL, SBP, DBP, BMI, WC, waist-to-hip ratio, and the SF-12 scores, with no significant between-groups difference (p > 0.05). The high-volume HIIT group, however, showed more significant improvements in HbA1c, FBG, 2-hr PPBG, TG, LDL, and treadmill time to maximal exhaustion than the low-volume HIIT group (p < 0.05). The non-exercising group showed non-significant changes in all outcome measures (p > 0.05). Conclusion: Low-volume HIIT could be equally effective as high-volume HIIT for improving TC, HDL, blood pressure, anthropometric adiposity measures, and HRQoL in obese women with type 2 diabetes. Nevertheless, high-volume HIIT could have a greater impact on glycemic control, TG, LDL, and cardiorespiratory fitness in these patients. Trial registration: ClinicalTrials.gov, NCT05110404.

Effects of aerobic, resistance, and combined training on thyroid function and quality of life in hypothyroidism. A randomized controlled trial.

PURPOSE: This study aimed to compare the effects of aerobic, resistance, and combined exercises on thyroid function, lipid profile, exercise capacity, and quality of life (QoL) in hypothyroid women. METHODS: Sixty women aged 35 to 45 with clinical hypothyroidism were randomized to four equal groups: aerobic training (AT), resistance training (RT), combined AT/RT, and control groups. All exercises were performed at low to moderate intensity, three days per week, and for 12 weeks. Patients in all groups were on levothyroxine therapy. Outcome measures were free thyroxin (T4), thyroid stimulating hormone (TSH), lipid profile, estimated maximal oxygen consumption (VO2 max) and QoL assessed by the 12-item Short Form (SF-12) Health Survey. RESULTS: All exercise groups showed significant improvements in all outcome measures compared to the baseline and the controls (p < 0.05). The combined AT/RT group showed more significant improvements in TSH and the mental component summary score of the SF-12 compared to the AT and RT groups (p < 0.05). The AT group showed the most significant improvement in estimated VO2 max, followed by the combined AT/RT and then the RT group. Non-significant differences were found between exercise groups in T4, blood lipids, and the physical component summary score of the SF-12 (p > 0.05). CONCLUSION: In women with hypothyroidism on levothyroxine treatment, all AT, RT, and combined AT/RT could equally improve T4 levels, lipid profile, and physical health-related QoL. However, the combined AT/RT could induce the greatest improvements in TSH and mental health-related QoL, while the AT could have the greatest impact on exercise capacity in these patients. TRIAL REGISTRATION: Pan African Clinical Trial Registry (PACTR), retrospective, PACTR202305810673587.