Explore the Relationship Between Heart Rate Variability, Body Mass Index, Inflammation, and Insulin Resistance.

Explore the Relationship Between Heart Rate Variability, Body Mass Index, Inflammation, and Insulin Resistance.

Explore the Relationship Between Heart Rate Variability, Body Mass Index, Inflammation, and Insulin Resistance: From a Population-based Survey to Multi-arms of Aerobic Exercise Intervention.

The findings will serve as a reference for clinical professionals to promote exercise among the general population and will provide evidence of whether different exercise amounts are recommended for individuals with different BMIs for improving HRV.

Background: Heart rate variability (HRV) measurement is widely used to assess the function of cardiac autonomic modulation. Aerobic exercise (AE) has been proven to improve HRV. However, because HRV is highly associated with visceral fat, inflammatory status, and insulin resistance, whether baseline body inflammation status can explain the heterogeneous response to AE remains unknown. Purposes: We will (1) compare the effects of AE training in improving HRV, inflammatory markers, and insulin resistance between community residents with normal weight and overweight and (2) compare the effects of various amounts of AE on the improvement of HRV, inflammatory markers, and insulin resistance among community residents with overweight/obesity. Methods: A randomized control trial with purposive sampling will be used to recruit community residents aged 40-64 years with inactive habits in southern Taiwan. To obtain the targeted sample size of 96 participants, including 42 participants with normal weight and 54 participants with overweight, the study will conduct three recruitment waves and 16-week interventions. The participants with normal weight will be further randomly allocated to a group receiving AE training with at least moderate intensity three times per week or a control group, whereas the participants with overweight will be randomly allocated to a group receiving the same prescribed AE training three times per week, a group receiving AE training five times per week (with additional home-based exercise two times per week), or a control group. HRV parameters, blood samples, and visceral fat will be evaluated. The blood samples will be evaluated for adipocytokines (adiponectin and leptin), proflammatory cytokines (interleukin-1 and interleukin-6), and markers of insulin resistance (fasting glucose, insulin, glucagon-like peptide-1, and dipeptidyl peptidase-4). All participants will be evaluated at baseline (T0) and after a 16- week intervention (T1). In addition to these time points, HRV will be measured during every exercise session for participants in exercise groups. Generalized estimating equations will be used to determine whether baseline BMI is the key factor influencing the effects of AE and whether higher exercise amounts contribute to greater improvements in HRV in the overweight group. Relevance to clinical practice: The findings will serve as a reference for clinical professionals to promote exercise among the general population and will provide evidence of whether different exercise amounts are recommended for individuals with different BMIs for improving HRV.

Particiapnts will be randomly divided into two groups for the participants in normal weight group (Group A and B) and divided into three groups for the participants in overweight group (Group C, D, and E), respectively.

This will be a single-blinded study, wherein the data analyzer (PI) will be blinded but the participants and intervener will not be.

The participants in Groups A and C will receive AE three times per week, and those in Group D will receive AE five times per week (the same supervised AE protocol three times a week with additional home-based AE training with an instructional video two times a week). The exercise movements in the instructional video will be identical to those of the supervised exercise to enable the participants to easily perform the exercise at home. The participants in the two control groups (Groups B and E) will maintain their original lifestyle without any exercise intervention during the 16 weeks.

Inclusion Criteria: are aged between 40 and 64 years. had inactive habit (<3 days of physical activity per week and <30 minutes per session). can communicate in Mandarin or Taiwanese. Exclusion Criteria: underlying conditions, such as stroke, acute coronary artery diseases, handicap, pregnancy, and unstable hypertension, that may present risks for exercise training. smoking or alcohol abuse. currently being on a diet, and (d) lifestyles that may affect HRV and inflammatory biomarkers (e.g., shift work or habit of staying up late).