scholarly journals Time course of changes in V̇O2peak and O2 extraction during ramp cycle exercise following HIIT vs moderate-intensity continuous training in type 2 diabetes.

2021 ◽  
Author(s):  
Norita Gildea ◽  
Adam McDermott ◽  
Joel Rocha ◽  
Donal O'Shea ◽  
Simon Green ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Time Course ◽  
Near Infrared ◽  
Moderate Intensity ◽  
Control Group ◽  
Vastus Lateralis Muscle ◽  
Linear Segment ◽  
Maximal Heart Rate ◽  
Low Volume

In the present study we assessed the time course of adaptations in peak oxygen uptake (V̇O2peak) and muscle fractional oxygen (O2) extraction (using near-infrared spectroscopy) following 12 weeks of low-volume high-intensity interval training (HIIT) vs. moderate-intensity continuous endurance training (MICT) in adults with uncomplicated type 2 diabetes (T2D). Participants with T2D were randomly assigned to MICT (n = 12, 50 min of moderate-intensity cycling), HIIT (n = 9, 10 x 1 min at ~90% maximal heart rate) or to a non-exercising control group (n = 9). Exercising groups trained 3 times per week and measurements were taken every 3 weeks. The rate of muscle deoxygenation (i.e. deoxygenated haemoglobin and myoglobin concentration, Δ[HHb+Mb]) profiles of the vastus lateralis muscle were normalised to 100% of the response, plotted against % power output (PO) and fitted with a double linear regression model. V̇O2peak increased (P<0.05) by week 3 of MICT (+17%) and HIIT (+8%), with no further significant changes thereafter. Total increases in V̇O2peak posttraining (P<0.05) were 27% and 14% respectively. The %∆[HHb+Mb] vs %PO slope of the first linear segment (slope1) was reduced (P<0.05) beyond 3 weeks of HIIT and MICT with no further significant changes thereafter. No changes in V̇O2peak or slope1 were observed in the control group. Low-volume HIIT and MICT induced improvements in V̇O2peak following a similar time course and these improvements were likely, at least in part, due to an improved microvascular O2 delivery.

Time-course of V̇O2 kinetics responses during moderate-intensity exercise subsequent to HIIT vs moderate-intensity continuous training in type 2 diabetes.

2021 ◽  
Author(s):  
Norita Gildea ◽  
Adam McDermott ◽  
Joel Rocha ◽  
Donal O'Shea ◽  
Simon Green ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Time Course ◽  
Near Infrared ◽  
Vastus Lateralis ◽  
Moderate Intensity ◽  
Vastus Lateralis Muscle ◽  
Maximal Heart Rate ◽  
Continuous Training ◽  
Muscle Deoxygenation

We assessed the time course of changes in oxygen uptake (V̇O2) and muscle deoxygenation (i.e., deoxygenated haemoglobin and myoglobin, [HHb+Mb]) kinetics during transitions to moderate-intensity cycling following 12-weeks of low-volume high-intensity interval training (HIIT) vs. moderate-intensity continuous training (MICT) in adults with type 2 diabetes (T2D). Participants were randomly assigned to MICT (n=10, 50 min of moderate-intensity cycling), HIIT (n=9, 10x1 min at ~90% maximal heart rate) or non-exercising control (n=9) groups. Exercising groups trained 3 times per week and measurements were taken every 3 weeks. [HHb+Mb] kinetics were measured by near-infrared spectroscopy at the vastus lateralis muscle. The local matching of O2 delivery to O2 utilization was assessed by the Δ[HHb+Mb]/ΔV̇O2ratio. The pretraining time constant of the primary phase of V̇O2 (τV̇O2p ) decreased (P<0.05) at wk 3 of training in both MICT (from 44±12 to 32±5 s) and HIIT (from 42±8 to 32 ± 4 s) with no further changes thereafter; while no changes were reported in controls. The pretraining overall dynamic response of muscle deoxygenation (τ'[HHb+Mb]) was faster than τV̇O2p in all groups, resulting in Δ[HHb+Mb]/V̇O2p showing a transient "overshoot" relative to the subsequent steady-state level. After 3 wks, the Δ[HHb+Mb]/V̇O2p overshoot was eliminated only in the training groups, so that τ'[HHb+Mb] was not different to τV̇O2p in MICT and HIIT. The enhanced V̇O2 kinetics response consequent to both MICT and HIIT in T2D was likely attributed to a training-induced improvement in matching of O2 delivery to utilization.

scholarly journals Exercise Training Intensity and the Fitness-Fatness Index in Adults with Metabolic Syndrome: A Randomized Trial

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Joyce S. Ramos ◽  
Lance C. Dalleck ◽  
Mackenzie Fennell ◽  
Alex Martini ◽  
Talita Welmans ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Metabolic Syndrome ◽  
Cardiorespiratory Fitness ◽  
Mortality Risk ◽  
High Volume ◽  
Moderate Intensity ◽  
Metabolic Equivalents ◽  
The Metabolic Syndrome ◽  
Low Volume

Abstract Background Cardiorespiratory fitness and fatness (notably central obesity) are mediating factors of the metabolic syndrome (MetS) and consequent cardiovascular disease (CVD)/mortality risk. The fitness-fatness index (FFI) combines these factors and has been reported to be a better indicator of CVD and all-cause mortality risk, beyond the capacity of either fitness or fatness alone. Objective This study sought to investigate the effects of different exercise intensities on FFI in adults with MetS. Methods This was a sub-study of the ‘Exercise in the prevention of Metabolic Syndrome’ (EX-MET) multicentre trial. Ninety-nine adults diagnosed with MetS according to the International Diabetes Federation criteria were randomized to one of the following 16-week exercise interventions: i) moderate-intensity continuous training (MICT) at 60–70% HRpeak for 30 min/session (n = 34, 150 min/week); ii) 4 × 4 min bouts of high-intensity interval training at 85–95% HRpeak, interspersed with 3-min active recovery at 50–70% HRpeak (n = 34, 38 min/session, 114 min/week); and iii) 1 × 4 min bout of HIIT at 85–95% HRpeak (n = 31, 17 min/session, 51 min/week). Cardiorespiratory fitness (peak oxygen uptake, V̇O2peak) was determined via indirect calorimetry during maximal exercise testing and fatness was the ratio of waist circumference-to-height (WtHR). FFI was calculated as V̇O2peak in metabolic equivalents (METs) divided by WtHR. A clinically meaningful response to the exercise intervention was taken as a 1 FFI unit increase. Results Seventy-seven participants completed pre and post testing to determine FFI. While there was no significant between group difference (p = 0.30), there was a small group x time interaction effect on FFI [F(2, 73) = 1.226; η2 = 0.01], with numerically greater improvements following HIIT (4HIIT, + 16%; 1HIIT, + 11%) relative to MICT (+ 7%). There was a greater proportion of participants who had a clinically meaningful change in FFI following high-volume HIIT (60%, 15/25) and low-volume HIIT (65%, 17/26) compared to MICT (38%, 10/26), but with no significant between-group difference (p = 0.12). A similar trend was found when a sub-analysis comparing the FFI between those with type 2 diabetes (MICT, 33%, 3/9; high-volume HIIT, 64%, 7/11; and low-volume HIIT, 58%, 7/12) and without type 2 diabetes (MICT, 41%, 7/17; high-volume HIIT, 57%, 8/14; low-volume HIIT, 71%, 10/14). Conclusion Although there were no statistically significant differences detected between groups, this study suggests that the response to changes in FFI in adults with MetS may be affected by exercise intensity, when numerical differences between exercise groups are considered. Further research is warranted. Trial registration number and date of registration: ClinicalTrials.gov NCT01676870; 31/08/2012.

scholarly journals Effect of Different HIIT Protocols on the Glycemic Control and Lipids Profile in Men with type 2 diabetes: A Randomize Control Trial

2020 ◽  
Author(s):  
Hessam Golshan ◽  
Mohammadreza Esmaelzadeh Toloee ◽  
Hamid Abbasi ◽  
Nasim Namiranian
Keyword(s):  
Type 2 Diabetes ◽  
High Volume ◽  
Control Group ◽  
P Value ◽  
Diabetic Patients ◽  
Type 2 Diabetic Patients ◽  
Significant Difference ◽  
Low Volume ◽  
Type 2 Diabetic

Objective: : High intensity interval training (HIITs) can induce weight control, lowering blood pressure and beneficial effects on cardiovascular health in type 2 diabetic patients. The effect of different volumes of these exercises is unclear in type 2 diabetic patients. The aim of this study was to compare the effect of low volume and high volume of short-term intensive training on glycemic indexes of men with type 2 diabetes. Materials and Methods: Thirty type 2 diabetes male patients who were referred to Yazd diabetes research center (30 - 46 years old) were selected and randomly divided into 3 groups of low and high volume HIITs groups and control group. The intensity of the exercises in low volume was up to 110% and in high volume up to 80% of the maximum heart rate. The two training groups performed exercises 3 days of week for 8 weeks. Glycemic factors and lipids profile were measured before and after the last training session. Data were analyzed by covariance and paired T-test. Results: Low volume HIIT exercises significantly decreased the glucose ( P -value: 0.01), HbA1c ( P -value: 0.01), insulin ( P -value: 0.005), insulin resistance ( P -value: 0.001), and triglyceride ( P -value: 0.04). Low volume HIIT in the insulin resistance had a significant difference with the control group ( P -value: 0.04). High density lipoprotein in high volume group had a significant difference with the control group ( P -value: 0.021). Conclusion: Low-volume HIIT exercises can be a nonpharmacological approach to improving glycemic factors in type 2 diabetic patients.

scholarly journals The effect of a novel low-volume aerobic exercise intervention on liver fat in type 2 diabetes: a randomised controlled trial

2020 ◽  
Author(s):  
Angelo Sabag ◽  
Kimberley L. Way ◽  
Rachelle N. Sultana ◽  
Shelley E. Keating ◽  
James A. Gerofi ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Cardiorespiratory Fitness ◽  
High Intensity ◽  
Exercise Intervention ◽  
Controlled Trial ◽  
Liver Fat ◽  
Moderate Intensity ◽  
Resonance Spectroscopy ◽  
Low Volume

Objective: The aim of this study was to examine the effect of a novel low-volume high-intensity interval training (HIIT), moderate-intensity continuous training (MICT) or placebo (PLA) intervention on liver fat, glycaemia, and cardiorespiratory fitness using a randomised placebo-controlled design. <p>Research design and methods: Thirty-five inactive adults (54.6±1.4 years, 54% male; BMI 35.9±0.9kg/m2) with obesity and type 2 diabetes were randomised to 12 weeks of supervised: MICT (n=12) at 60% VO<sub>2peak</sub> for 45 minutes, 3 days/week, HIIT (n=12) at 90% VO<sub>2peak</sub> for 4 minutes, 3 days/week, or PLA (n=11). Liver fat % was quantified via proton magnetic resonance spectroscopy.</p> <p>Results: Liver fat reduced in MICT (-0.9±0.7%) and HIIT (-1.7±1.1%) but increased in PLA (1.2±0.5%) (p = 0.046). HbA1c improved in MICT (-0.3±0.3%) and in HIIT (-0.3±0.3%) but not in PLA (0.5±0.2%) (p=0.014). Cardiorespiratory fitness improved in MICT (2.3±1.2 ml/kg/min) and HIIT (1.1±0.5 ml/kg/min) but not in PLA (-1.5±0.9 ml/kg/min) (p=0.006). </p> <p>Conclusions: MICT or a low-volume HIIT approach involving 12 minutes of weekly high-intensity exercise may improve liver fat, glycaemia, and cardiorespiratory fitness in type 2 diabetes in the absence of weight loss. Further studies are required to elucidate the relationship between exercise-induced reductions in liver fat and improvements in glycaemia.</p>

scholarly journals The effect of a novel low-volume aerobic exercise intervention on liver fat in type 2 diabetes: a randomised controlled trial

2020 ◽  
Author(s):  
Angelo Sabag ◽  
Kimberley L. Way ◽  
Rachelle N. Sultana ◽  
Shelley E. Keating ◽  
James A. Gerofi ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Cardiorespiratory Fitness ◽  
High Intensity ◽  
Exercise Intervention ◽  
Controlled Trial ◽  
Liver Fat ◽  
Moderate Intensity ◽  
Resonance Spectroscopy ◽  
Low Volume

Objective: The aim of this study was to examine the effect of a novel low-volume high-intensity interval training (HIIT), moderate-intensity continuous training (MICT) or placebo (PLA) intervention on liver fat, glycaemia, and cardiorespiratory fitness using a randomised placebo-controlled design. <p>Research design and methods: Thirty-five inactive adults (54.6±1.4 years, 54% male; BMI 35.9±0.9kg/m2) with obesity and type 2 diabetes were randomised to 12 weeks of supervised: MICT (n=12) at 60% VO<sub>2peak</sub> for 45 minutes, 3 days/week, HIIT (n=12) at 90% VO<sub>2peak</sub> for 4 minutes, 3 days/week, or PLA (n=11). Liver fat % was quantified via proton magnetic resonance spectroscopy.</p> <p>Results: Liver fat reduced in MICT (-0.9±0.7%) and HIIT (-1.7±1.1%) but increased in PLA (1.2±0.5%) (p = 0.046). HbA1c improved in MICT (-0.3±0.3%) and in HIIT (-0.3±0.3%) but not in PLA (0.5±0.2%) (p=0.014). Cardiorespiratory fitness improved in MICT (2.3±1.2 ml/kg/min) and HIIT (1.1±0.5 ml/kg/min) but not in PLA (-1.5±0.9 ml/kg/min) (p=0.006). </p> <p>Conclusions: MICT or a low-volume HIIT approach involving 12 minutes of weekly high-intensity exercise may improve liver fat, glycaemia, and cardiorespiratory fitness in type 2 diabetes in the absence of weight loss. Further studies are required to elucidate the relationship between exercise-induced reductions in liver fat and improvements in glycaemia.</p>

scholarly journals Exercise Training Volume and the Fitness-fatness Index in Adults With Metabolic Syndrome: A Randomised Trial

2021 ◽  
Author(s):  
Joyce S. Ramos ◽  
Lance C. Dalleck ◽  
Mackenzie Fennell ◽  
Alex D. Martini ◽  
Talita R. Welmans ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Metabolic Syndrome ◽  
Cardiorespiratory Fitness ◽  
Mortality Risk ◽  
High Volume ◽  
Moderate Intensity ◽  
Metabolic Equivalents ◽  
The Metabolic Syndrome ◽  
Low Volume

Abstract Background Cardiorespiratory fitness and fatness (notably central obesity) are mediating factors of the metabolic syndrome (MetS), and consequent cardiovascular disease (CVD)/mortality risk. The fitness-fatness index (FFI) combines these factors and has been reported to be a better indicator of CVD and all-cause mortality risk, beyond the capacity of either fitness or fatness alone. Objective This study sought to investigate the effects of different exercise volumes on FFI in adults with MetS. Methods This was a sub-study of the ‘Exercise in the prevention of Metabolic Syndrome’ (EX-MET) multicenter trial. Ninety-nine adults diagnosed with MetS according to the International Diabetes Federation criteria were randomized to one of the following 16-week exercise interventions: i) moderate-intensity continuous training (MICT) at 60-70% HRpeak for 30 min/session (n=34, 150 min/week); ii) 4 x 4 min bouts of high-intensity interval training at 85-95% HRpeak, interspersed with 3-min active recovery at 50-70% HRpeak (n=34, 38min/session, 114 mins/week); and iii) 1 x 4 min bout of HIIT at 85-95% HRpeak (n=31, 17 min/session, 51 min/week). Cardiorespiratory fitness (peak oxygen uptake, V̇O2peak) was determined via indirect calorimetry during maximal exercise testing and fatness was the ratio of waist circumference-to-height (WHtR). FFI was calculated as V̇O2peak in metabolic equivalents (METs) divided by WHtR. A clinically meaningful response to the exercise intervention was taken as a 1 FFI unit increase. Results Seventy-seven participants completed pre and post testing to determine FFI. There was a greater proportion of participants who had a clinically meaningful change in FFI following high-volume HIIT (60%, 15/25) and low-volume HIIT (65%, 17/26) compared to MICT (38%, 10/26), but with no significant between-group difference (p=0.12). A similar trend was found when a sub-analysis comparing the FFI between those with type 2 diabetes (MICT, 33%, 3/9; high-volume HIIT, 64%, 7/11; and low-volume HIIT, 58%, 7/12) and without type 2 diabetes (MICT, 41%, 7/17; high-volume HIIT, 57%, 8/14; low-volume HIIT, 71%, 10/14). Conclusion This study suggests that the response to changes in FFI in adults with MetS is affected by aerobic exercise intensity.

scholarly journals Influence of priming exercise on oxygen uptake and muscle deoxygenation kinetics during moderate-intensity cycling in type 2 diabetes

2019 ◽  
Vol 127 (4) ◽  
pp. 1140-1149 ◽  
Author(s):  
Joel Rocha ◽  
Norita Gildea ◽  
Donal O’Shea ◽  
Simon Green ◽  
Mikel Egaña
Keyword(s):  
Type 2 Diabetes ◽  
Infrared Spectroscopy ◽  
Oxygen Uptake ◽  
Near Infrared ◽  
Moderate Intensity ◽  
Middle Aged ◽  
Pulmonary Oxygen Uptake ◽  
Muscle Deoxygenation ◽  
Priming Exercise

The pulmonary oxygen uptake (V̇o2) kinetics during the transition to moderate-intensity exercise is slowed in individuals with type 2 diabetes (T2D), at least in part because of limitations in O2 delivery. The present study tested the hypothesis that a prior heavy-intensity warm-up or “priming” exercise (PE) bout would accelerate V̇o2 kinetics in T2D, because of a better matching of O2 delivery to utilization. Twelve middle-aged individuals with T2D and 12 healthy controls (ND) completed moderate-intensity constant-load cycling bouts either without (Mod A) or with (Mod B) prior PE. The rates of muscle deoxygenation (i.e., deoxygenated hemoglobin and myoglobin concentration, [HHb+Mb]) and oxygenation (i.e., tissue oxygenation index) were continuously measured by near-infrared spectroscopy at the vastus lateralis muscle. The local matching of O2 delivery to O2 utilization was assessed by the Δ[HHb+Mb]-to-ΔV̇o2 ratio. Both groups demonstrated an accelerated V̇O2 kinetics response during Mod B compared with Mod A (T2D, 32 ± 9 vs. 42 ± 12 s; ND, 28 ± 9 vs. 34 ± 8 s; means ± SD) and an elevated muscle oxygenation throughout Mod B, whereas the [HHb+Mb] amplitude was greater during Mod B only in individuals with T2D. The [HHb+Mb] kinetics remained unchanged in both groups. In T2D, Mod B was associated with a decrease in the “overshoot” relative to steady state in the Δ[HHb+Mb]-to-ΔV̇o2 ratio (1.17 ± 0.17 vs. 1.05 ± 0.15), whereas no overshoot was observed in the control group before (1.04 ± 0.12) or after (1.01 ± 0.12) PE. Our findings support a favorable priming-induced acceleration of the V̇o2 kinetics response in middle-aged individuals with uncomplicated T2D attributed to an enhanced matching of microvascular O2 delivery to utilization. NEW & NOTEWORTHY Heavy-intensity “priming” exercise (PE) elicited faster pulmonary oxygen uptake (V̇o2) kinetics during moderate-intensity cycling exercise in middle-aged individuals with type 2 diabetes (T2D). This was accompanied by greater near-infrared spectroscopy-derived muscle deoxygenation (i.e., deoxygenated hemoglobin and myoglobin concentration, [HHb+Mb]) responses and a reduced Δ[HHb+Mb]-to-ΔV̇o2 ratio. This suggests that the PE-induced acceleration in oxidative metabolism in T2D is a result of greater O2 extraction and better matching between O2 delivery and utilization.

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