High-intensity interval training or continuous training, combined or not with fasting, in obese or overweight women with cardiometabolic risk factors: study protocol for a randomised clinical trial

Association of Physical Activity with Retinal Thickness and Vascular Structure in Elderly Chinese Population

INTRODUCTION

We aimed to assess the association of physical activity (PA) with retinal thickness and vascular structure in an elderly Chinese population.

METHODS

This study enrolled 220 retirees aged 50 years and above from Tianjin University of Sport, China. PA data gathered through the International Physical Activity Questionnaires were computed for metabolic equivalent of task-minutes per week. All participants underwent full ophthalmic examination including optical coherence tomography angiography. Multiple linear regression analyses were used to evaluate the association of PA with retinal thickness and vascular structure.

RESULTS

A high amount of total PA was associated with smaller size of foveal avascular zone (FAZ) (high vs. low: area, β = -0.04; circumference β = -0.14) and greater central vessel density (VD) (β = 1.04) and perfusion density (PD) (β = 0.02). For domain-specific PA, participants with high and moderate recreational PA levels were found to have greater central VDs and PDs. Nonleisure activities demonstrated negative relationship with FAZ perimeter ratio (moderate vs. low: β = -0.08; high vs. low: β = -0.13) and, counter-intuitively, negative relation with VDs measured at the inner (high vs. low: β = -0.98) and outer retinal layers (high vs. low: β = -0.38). Additionally, higher levels of total PA were related to increased macular fovea thickness and average thickness of retinal nerve fiber layer.

CONCLUSIONS

High PA level, particularly recreational PA, was associated with smaller FAZ and greater VD and PD in senior adults. Nonleisure-time PA might not confer the same health benefits as leisure-time PA. Our data support a possible protective role of recreational PA in the retina against microvascular changes.

Acute effect of high-intensity interval exercise on vascular endothelial function and possible mechanisms of wall shear stress in young obese males

Objective: To investigate the mechanisms of wall shear stress (WSS) responsible for the effects of high-intensity interval exercise (HIIE) on vascular endothelial function in young obese males.

Methods: A within-subject study design was used. We examined the response of the reactive hyperemia index (RHI) to acute HIIE in young obese males (n = 20, age = 20.38 ± 1.40 years, body mass index [BMI] = 31.22 ± 3.57, body fat percentage [BF (%)] = 31.76 ± 3.57). WSS was manipulated using 100, 80, or 60 mmHg cuff inflation during the HIIE to determine the proper inflation capable of maintaining WSS near baseline levels. One-way repeated measures analysis of variance and LSD post hoc tests were performed to compare changes in WSS and vascular endothelial function at baseline HIIE and following HIIE using different cuff inflations.

Results: There were no significant differences in RHI and WSS between the three cuff inflation values (p > 0.05). WSS was significantly higher in obese male individuals after HIIE and HIIE with 100 mmHg cuff inflation (p = 0.018, p = 0.005) than that at baseline, with no significant differences observed comparing HIIE and HIIE with 100 mmHg inflation (p = 0.23). The RHI after HIIE was significantly higher (p = 0.012) than that at baseline, while no significant differences were detected after HIIE at 100 mmHg (p = 0.91). The RHI was significantly lower after HIIE with 100 mmHg than that after HIIE (p = 0.007). WSS (p = 0.004) and RHI (p = 0.017) were significantly higher after HIIE than that at baseline, while no significant differences were observed after HIIE with either 80 or 60 mmHg cuff inflation (baseline vs. HIIE + 80 mmHg: WSS: p = 0.33, RHI: p = 0.38; baseline vs. HIIE + 60 mmHg: WSS: p = 0.58, RHI: p = 0.45). WSS was similar to HIIE, after HIIE with either 80 or 60 mmHg inflation (p = 0.36, p = 0.40). However, RHI was significantly higher for HIIE than for HIIE with both 80 and 60 mmHg inflation (p = 0.011, p = 0.006).

Conclusion: HIIE could significantly improve WSS and vascular endothelial function. HIIE intervention with 60 or 80 mmHg inflation might enhance WSS near the baseline level. HIIE-induced acute changes in WSS may provide the primary physiological stimulus for vascular endothelial adaptation to HIIE in young obese males.

High-Intensity Interval Circuit Training Versus Moderate-Intensity Continuous Training on Functional Ability and Body Mass Index in Middle-Aged and Older Women: A Randomized Controlled Trial

The literature suggests that high-intensity interval training (HIIT) is more effective than moderate-intensity continuous training (MICT) to improve functional ability. However, there is no evidence on including HIIT in a circuit programme (HIICT). Our objective was to determine what type of training (HIICT or MICT) induces greater adaptations in the functional ability and body mass index of middle-aged and older women. The study used a quasi-experimental randomized controlled trial with 54 participants (age = 67.8 ± 6.2 years). Participants were randomly allocated to HIICT (n = 18), MICT (n = 18) or a non-exercise control group (CG; n = 18). The participants in the HIICT or MICT groups trained twice a week (1 h/session) for 18 weeks. Forty-one subjects were analysed (HIICT; n = 17, MICT; n = 12, CG; n = 12). Five subjects presented adverse events during the study. Strength, gait, cardiorespiratory fitness, balance and body mass index were measured. A significant training x group interaction was found in the arm curl test, where HIICT was statistically better than MICT and CG. Likewise, HIICT was statistically better than the CG in the BMI interaction. In lower limb strength, gait/dynamic balance and cardiorespiratory fitness, both HIICT and MICT were statistically better than the CG. In conclusion, HIICT generated better adaptations in upper limb strength than MICT. Likewise, HIICT generated better adaptations in body mass index than CG. Finally, both HIICT and MICT had a similar influence on strength, cardiorespiratory fitness and gait/dynamic balance.

Effects of Polarized Training on Cardiometabolic Risk Factors in Young Overweight and Obese Women: A Randomized-Controlled Trial

Introduction: Volume and intensity are major variables governing exercise training-mediated beneficial effects in both athletes and patients. Although polarized endurance training optimizes and maximizes physiological gains in highly trained individuals, its cardiometabolic protective-effects have not been established. The purpose of the present single site, randomized-controlled trial was to compare the effects of 12-weeks of high-intensity interval training (HIIT), moderate-intensity continuous training (MICT), and polarized volume training (POL) programs on cardiometabolic risk factors in young overweight and obese women.

Materials and Methods: A total of 64 overweight/obese young women (age 23.3 ± 3.8 years, body mass index 33.8 ± 3.8 kg/m²) were randomly assigned to four groups: control group (CTRL), polarized volume training group, moderate-intensity endurance training group, and HIIT group. The cardiorespiratory capacity, glycemic and lipid profiles, whole-body substrate utilization, and body composition were assessed before and after the intervention.

Results: After the intervention, VO_2peak and power output at VO_2peak increased in all exercised-groups (time effect: p < 0.0001). Power output at VT1 was increased only in the POL group compared to the CTRL group (p = 0.019). Relative fold changes in fasting plasma glucose concentrations decreased only in POL group (p = 0.002). Training induced a significant increase in relative fat oxidation in all the groups (time effect: p < 0.001). Relative fat oxidation increased only in the POL group compared to the CTRL group (training effect: p = 0.032).

Conclusion: Twelve-weeks of polarized volume training showed overall superior effects on cardiorespiratory fitness, basal glycemic control, and substrate oxidation in comparison to MICT and HIIT training modalities. These data suggest that polarized volume training is an effective non-pharmacological treatment strategy for reducing cardiovascular disease risk factors in young overweight and obese women. The trial is registered at ISRCTN, number ISRCTN34421723.