Effect of Two Doses of Interval Training on Maximal Fat Oxidation in Sedentary Women (original) (raw)
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Journal of applied …, 2007
Unpicking the molecular basis by which omega3 fatty acids alter skeletal muscle metabolism. View project ABSTRACT Our aim was to examine the effects of seven high intensity aerobic interval training (HIIT) sessions over two weeks on skeletal muscle fuel content, mitochondrial enzyme activities, fatty acid transport proteins, VO 2 peak, and whole body metabolic, hormonal and cardiovascular responses to exercise. Eight females participated in the study (22.1 ± 0.2 yrs, 65.0 ± 2.2 kg, VO 2 peak: 2.36 ± 0.24 l min -1 ). Subjects performed a VO 2 peak test and a 60-min cycling trial at ~60% VO 2 peak prior to and following training. Each session consisted of ten, 4-min bouts at ~90% VO 2 peak with 2-min rest between intervals. Training increased VO 2 peak by 13%.
Obesity Research & Clinical Practice, 2013
Purpose: The objectives of this study were to examine the effect of 4-week moderate-and high-intensity interval training (MIIT and HIIT) on fat oxidation and the responses of blood lactate (BLa) and rating of perceived exertion (RPE). Methods: Ten overweight/obese men (age = 29 ±3.7 years, BMI = 30.7 ±3.4 kg/m 2) participated in a cross-over study of 4-week MIIT and HIIT training. The MIIT training sessions consisted of 5-min cycling stages at mechanical workloads 20% above and 20% below 45%VO 2peak. The HIIT sessions consisted of intervals of 30-s work at 90% VO 2peak and 30-s rest. Pre-and post-training assessments included VO 2max using a graded exercise test (GXT) and fat oxidation using a 45-min constant-load test at 45%VO 2max. BLa and RPE were also measured during the constantload exercise test. Results: There were no significant changes in body composition with either intervention. There were significant increases in fat oxidation after MIIT and HIIT (p ≤ 0.01), with no effect of intensity. BLa during the constant-load exercise test significantly decreased after MIIT and HIIT (p ≤ 0.01), and the difference between MIIT and HIIT was not significant (p = 0.09). RPE significantly decreased after HIIT greater than MIIT (p ≤ 0.05). Conclusion: Interval training can increase fat oxidation with no effect of exercise intensity, but BLa and RPE decreased after HIIT to greater extent than MIIT.
Nutrients
The effects of two high-intensity interval training (HIIT) protocols on regional body composition and fat oxidation in men with obesity were compared using a parallel randomized design. Sixteen inactive males (age, 38.9 ± 7.3 years; body fat, 31.8 ± 3.9%; peak oxygen uptake, VO2peak, 30.9 ± 4.1 mL/kg/min; all mean ± SD) were randomly assigned to either HIIT10 (48 × 10 s bouts at 100% of peak power [Wpeak] with 15 s of recovery) or HIIT60 group (8 × 60 s bouts at 100% Wpeak with 90 s of recovery), and subsequently completed eight weeks of training, while maintaining the same diet. Analyses of variance (ANOVA) showed only a main effect of time (p < 0.01) and no group or interaction effects (p > 0.05) in the examined parameters. Total and trunk fat mass decreased by 1.81 kg (90%CI: −2.63 to −0.99 kg; p = 0.002) and 1.45 kg (90%CI: −1.95 to −0.94 kg; p < 0.001), respectively, while leg lean mass increased by 0.86 kg (90%CI: 0.63 to 1.08 kg; p < 0.001), following both HIIT pr...
The aim of the study was to determine the rate of fat oxidation during continuous and intermittent acute endurance exercise. Eleven healthy untrained men participated in this study. Subjects performed Bruce protocol test on cycle ergometer to determine maximal oxygen consumption (VO2max). The exercise intensity in which the highest fat oxidation rate occurs was determined in this exercise test for each subject. Oxygen uptake (VO2) and carbon dioxide (VCO2) production during the exercises were followed by respiratory gas analyzer and whole-body fat oxidation was calculated by indirect calorimeter equations. Subjects performed 45min intermittent (IE) and continuous (CE) exercises in respiratory exchange ratio (RER) at intensity correspondent at the highest fat oxidation rate (Fat max). The peak fat oxidation rate was equal to 40.6% of maximum oxygen consumption of subjects. The changes occurring with time in fat (F=20.67) and carbohydrate (F=19.44) oxidation rates were statistically significant (P<0.01). However, the changes of fat and carbohydrate (CHO) oxidation with time did not show any statistically significant differences between the continuous and intermittent exercises (P>0.05). The results of the study indicate that the continuous and intermittent exercises performed at the exercise intensity ensuring maximum fat oxidation rate provide similar fat oxidation. Especially, for the individuals starting regular exercise applications newly, it can be said that similar positive results regarding fat oxidation can also be obtained by avoiding the insipidity of long lasting exercises and giving breaks.
A single versus multiple bouts of moderate-intensity exercise for fat metabolism
Clinical Physiology and Functional Imaging, 2011
This study compared the fat metabolism between Ôa single bout of 30-min exerciseÕ and Ôthree bouts of 10-min exerciseÕ of the same intensity (60% maximal oxygen uptake) and total exercise duration (30 min). Nine healthy men participated in three trials: (1) a single 30-min bout of exercise (Single), (2) three 10-min bouts of exercise, separated by a 10-min rest (Repeated) and (3) rest (Rest). Each exercise was performed with a cycle ergometer at 60% of maximal oxygen uptake, followed by 180-min rest. Blood lactate concentration increased significantly after exercise in the Single and Repeated trials (P<0AE05), but the Single trial showed a significantly higher value during the recovery period (P<0AE05). No significant difference was observed in the responses of plasma glycerol concentration. The Repeated trial produced a smaller increase in the ratings of perceived exertion during the exercise (P<0AE01). During the exercise, no significant difference was observed in respiratory exchange ratio (RER) between the Single and Repeated trials. However, the RER values during the recovery period were significantly lower in the Repeated trial than in the Single and Rest trials (P<0AE05), indicating higher relative contribution of fat oxidation in the Repeated trial (P<0AE05). These results suggest that the repetition of 10-min of moderate exercise can contribute to greater exercise-induced fat oxidation compared with a single 30-min bout of continuous exercise.
Determination of the exercise intensity that elicits maximal fat oxidation
2002
Purpose: The aim of this study was to develop a test protocol to determine the exercise intensity at which fat oxidation rate is maximal (Fatm-a). Method: Eighteen moderately trained cyclists performed a graded exercise test to exhaustion, with 5-min stages and 35-W increments (GE 351 5). In addition, four to six continuous prolonged exercise tests (CE) at constant work rates, corresponding to the work rates of the GE test, were performed on separate days. The duration of each test was chosen so that all trials would result in an equal energy expenditure. Seven other subjects performed three different GE tests to exhaustion. The test protocols differed in stage duration and in increment size. Fat oxidation was measured using indirect calorimetry. Results: No significant differences were found in Fatmax determined with the GE 35 / 5 , the average fat oxidation of the CE tests, or fat oxidation measured during the first 5 min of the CE tests (56 + 3, 64 + 3, 58 + 3%V 2 ,Oax, respectively). Results of the GE 35 6 5 protocol were used to construct an exercise intensity versus fat oxidation curve for each individual. Fatrax was equivalent to 64 + 4%VO 2 ma-and 74 ± 3%HRmax. The Fatmax zone (range of intensities with fat oxidation rates within 10% of the peak rate) was located between 55 ± 3 and 72 + 4%VO 2 ,ax. The contribution of fat oxidation to energy expenditure became negligible above 89-3%VO2n,ax (92 + I%HR,,a). When stage duration was reduced from 5 to 3 min or when increment size was reduced from 35 to 20 W, no significant differences were found in Fat_ax, Fatmin, or the Fat,,,, zone. Conclusion: It is concluded that a protocol with 3-min stages and 35-W increments in work rate can be used to determine Fatmax-Fat oxidation rates are high over a large range of intensities; however, at exercise intensities above Fatmax, fat oxidation rates drop markedly.
The acute effect of a single exhaustive sprint exercise session on post-exercise fat oxidation rate
Study aim: It is well known that substrate oxidation rates are increased by exercise. The present study had two main objectives: firstly, to examine the effect of a single exhaustive exercise session on post-exercise substrate oxidation and energy expenditure; and secondly, to determine the differences between athletes and non-athletes. Material and methods: Eighteen healthy male athletes (mean ± SD age; 19.38 ± 2.26 years, VO 2max ; 60.57 ± 3.90 ml · kg -1 · min -1 , n = 8) and non-athletes (age; 20.30 ± 1.26 years, VO 2max ; 44.97 ± 5.43 ml · kg -1 · min -1 , n = 10) volunteered to participate in the study. After an overnight fast, subjects performed a single sprint exercise session on a cycle ergometer with individual loads (0.075 kg per body weight) until volitional exhaustion. Energy expenditure (EE) and the substrate oxidation rate were measured at rest and during the post-exercise recovery period using indirect calorimetry. Results: Exhaustive exercise significantly increased post-exercise fat oxidation, energy expenditure and contribution of fat to EE (p < 0.05). Also, it significantly decreased post-exercise carbohydrate (CHO) oxidation and the contribution of CHO to EE (p < 0.05). However, the changes in the substrate oxidation rate and EE after the exercise test were not different between the groups (p > 0.05).
Journal of Applied Physiology, 2008
Perturbations in body weight have been shown to affect energy expenditure and efficiency during physical activity. The separate effects of weight loss and exercise training on exercise efficiency or the proportion of energy derived from fat oxidation during physical activity, however, are not known. The purpose of this study was to determine the separate and combined effects of exercise training and weight loss on metabolic efficiency, economy (EC), and fat oxidation during steady-state moderate submaximal exercise. Sixty-four sedentary older (67 ± 0.5 yr) overweight to obese (30.7 ± 0.4 kg/m2) volunteers completed 4 mo of either diet-induced weight loss (WL; n = 11), exercise training (EX; n = 36), or the combination of both interventions (WLEX; n = 17). Energy expenditure, gross efficiency (GE), EC, and proportion of energy expended from fat (EF) were determined during a 1-h submaximal (50% of peak aerobic capacity) cycle ergometry exercise before the intervention and at the same ...
Postexercise fat oxidation: effect of exercise duration, intensity, and modality
International journal of sport nutrition and exercise metabolism, 2009
Postexercise fat oxidation may be important for exercise prescription aimed at optimizing fat loss. The authors examined the effects of exercise intensity, duration, and modality on postexercise oxygen consumption (VO2) and substrate selection/ respiratory-exchange ratio (RER) in healthy individuals. Three experiments (n = 7 for each) compared (a) short- (SD) vs. long-duration (LD) ergometer cycling exercise (30 min vs. 90 min) matched for intensity, (b) low- (LI) vs. high-intensity (HI) cycling (50% vs. 85% of VO2(max)) matched for energy expenditure, and (c) continuous (CON) vs. interval (INT) cycling matched for energy expenditure and mean intensity. All experiments were administered by crossover design. Altering exercise duration did not affect postexercise VO2 or RER kinetics (p > .05). However, RER was lower and fat oxidation was higher during the postexercise period in LD vs. SD (p < .05). HI vs. LI resulted in a significant increase in total postexercise energy expendi...