The effects of high-intensity intermittent exercise training on fat loss and fasting insulin levels of young women. International Journal of Obesity, 32(4), 684-691

Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia.
International journal of obesity (2005) (Impact Factor: 5). 04/2008; 32(4):684-91. DOI: 10.1038/sj.ijo.0803781
Source: PubMed


To determine the effects of a 15-week high-intensity intermittent exercise (HIIE) program on subcutaneous and trunk fat and insulin resistance of young women.
Subjects were randomly assigned to one of the three groups: HIIE (n=15), steady-state exercise (SSE; n=15) or control (CONT; n=15). HIIE and SSE groups underwent a 15-week exercise intervention.
Forty-five women with a mean BMI of 23.2+/-2.0 kg m(-2) and age of 20.2+/-2.0 years.
Both exercise groups demonstrated a significant improvement (P<0.05) in cardiovascular fitness. However, only the HIIE group had a significant reduction in total body mass (TBM), fat mass (FM), trunk fat and fasting plasma insulin levels. There was significant fat loss (P<0.05) in legs compared to arms in the HIIE group only. Lean compared to overweight women lost less fat after HIIE. Decreases in leptin concentrations were negatively correlated with increases in VO(2peak) (r=-0.57, P<0.05) and positively correlated with decreases in TBM (r=0.47; P<0.0001). There was no significant change in adiponectin levels after training.
HIIE three times per week for 15 weeks compared to the same frequency of SSE exercise was associated with significant reductions in total body fat, subcutaneous leg and trunk fat, and insulin resistance in young women.

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Available from: Ethlyn Gail Trapp,
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    • "It is also well known, that resistance training may improve the muscle insulin sensitivity and β-cell function in obese patients (Croymans et al. 2013). HIIE three times per week for 15 weeks compared to the same frequency of steady-state exercise was associated with significant reductions in total body fat, subcutaneous leg and trunk fat, and insulin resistance in young women (Trapp et al. 2008). A 35% rise in glucagon concentration was positively correlated with the exercise intensity increase (Galbo et al. 1975). "
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    ABSTRACT: Obesity management for achieving an effective weight loss includes dietary modification and exercise [resistance (strength), endurance (cardiovascular) or intervals training (high-intensity intermittent exercise)]. Regular exercise acutely increases fat oxidation, which induces loss of fat mass and increases energy expenditure. Moreover, it has a positive effect on the physical (improved insulin sensitivity, lipid profile, etc.) and mental health (mood, cognition, memory, sleep, etc.). Endocrine responses to muscle actions are affected by many factors, including the exercise muscle groups (lower and upper body), load/volume, time-under tension, and rest-period intervals between sets, training status, gender, and age. The aim of this review is to summarize, evaluate, and clarify the literature data focusing on the endocrine responses to different types of exercise, including the frequency, intensity, and type of movement with regard to the fat loss strategies. Many studies have investigated anabolic [growth hormone, insulin-like growth factor-1 (IGF-1), testosterone] and gluco- and appetite- regulatory (insulin, cortisol, ghrelin) hormone responses and adaptations of skeletal muscles to exercise. Muscle tissue is a critical endocrine organ, playing important role in the regulation of several physiological and metabolic events. Moreover, we are also describing the response of some other substances to exercise, such as myokines [irisin, apelin, brain-derived neurotrophic factor (BDNF), myostatin, and fibroblast growth factor 21 (FGF21)]. It is proposed that reducing intra-abdominal fat mass and increasing cardiorespiratory fitness through improving nutritional quality, reducing sedentary behavior, and increase the participation in physical activity/exercise, might be associated with clinical benefits, sometimes even in the absence of weight loss.
    Endocrine regulations 08/2015; 49(3):151-63. DOI:10.4149/endo_2015_03_151
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    • "Furthermore, we demonstrated that EPOC is significantly greater following 10 min of REHIT compared to 30 min of moderate intensity aerobic exercise. These findings are of importance as several previous studies have observed reductions in fat mass following HIT with some evidence for superior reductions compared with traditional aerobic training (Whyte et al. 2010; Gillen et al. 2013; Heydari et al. 2012; Trapp et al. 2008). Since direct exercise energy expenditure is much lower with HIT compared with aerobic exercise, the (potentially superior) reductions in fat mass following HIT have been hypothesised to be a result of either an increase in energy expenditure through a more prolonged EPOC and/or a reduction in energy intake through suppression of appetite (Boutcher 2011). "
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    ABSTRACT: Purpose We have previously shown that 6 weeks of reduced-exertion high-intensity interval training (REHIT) improves V˙O2max in sedentary men and women and insulin sensitivity in men. Here, we present two studies examining the acute physiological and molecular responses to REHIT. Methods In Study 1, five men and six women (age: 26 ± 7 year, BMI: 23 ± 3 kg m−2, V˙O2max: 51 ± 11 ml kg−1 min−1) performed a single 10-min REHIT cycling session (60 W and two 20-s ‘all-out’ sprints), with vastus lateralis biopsies taken before and 0, 30, and 180 min post-exercise for analysis of glycogen content, phosphorylation of AMPK, p38 MAPK and ACC, and gene expression of PGC1α and GLUT4. In Study 2, eight men (21 ± 2 year; 25 ± 4 kg·m−2; 39 ± 10 ml kg−1 min−1) performed three trials (REHIT, 30-min cycling at 50 % of V˙O2max, and a resting control condition) in a randomised cross-over design. Expired air, venous blood samples, and subjective measures of appetite and fatigue were collected before and 0, 15, 30, and 90 min post-exercise. Results Acutely, REHIT was associated with a decrease in muscle glycogen, increased ACC phosphorylation, and activation of PGC1α. When compared to aerobic exercise, changes in V˙O2, RER, plasma volume, and plasma lactate and ghrelin were significantly more pronounced with REHIT, whereas plasma glucose, NEFAs, PYY, and measures of appetite were unaffected. Conclusions Collectively, these data demonstrate that REHIT is associated with a pronounced disturbance of physiological homeostasis and associated activation of signalling pathways, which together may help explain previously observed adaptations once considered exclusive to aerobic exercise.
    Arbeitsphysiologie 07/2015; DOI:10.1007/s00421-015-3217-6 · 2.19 Impact Factor
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    • "Shelley et al. also performed continued training programs on sedentary 18—55 years old adults and showed that more reduction in body fat occurred compared to the HIIT program [16]. However, Trapp et al. showed that 15 weeks of HIIT program interspaced by 8 seconds of rest interval followed by 12 seconds of recovery compared to steadystate exercise intensity resulted in considerable changes in total body fat, foot, truck and subcutaneous fat in young inactive female participants [17]. This finding is, despite the lack of increase in lean body, observed in persistence participation in aerobic exercise [18]. "
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    ABSTRACT: Background: High-intensity interval training programs are one of the effective means to improve lipid profiles. It has been claimed that the amount of some of the enzymes are indicative of the normal functioning of liver. The purpose of this research is to examine the effects of different recovery intervals different rest intervals during the High-intensity interval training programs on liver enzymes and serum lipid levels of overweight women. Methodology: Twenty-four volunteer women with mean aged 34.42±5.3years old with BMI 29.48±3.45kg/m2, weight of 80±0.08, height of 159.14±4.60cm, respectively were randomly assigned into three equal groups (n=8) of 60/60 activity-rest, 60/30 activity-rest and control. The exercise protocol included 4weeks of 4trials, three sessions per week at 80% reserved heart rate increased to 10trials in the fourth week. Results: Four weeks of HIIT sessions did not result in significant change in blood lipid profiles including HDL-C, HDL/LDL, cholesterol, TG, and liver enzymes (ALP, AST, and ALP) in addition to body composition (. P<. 0.05). There was a significant difference in the percentage of fat in the three groups (. P<. 0.05). In addition, there was a significant inverse association between the liver enzymes and HDL-C (. P<. 0.05). Conclusion: Based on the result of this research, 4weeks of HIIT activities result in no significant change in indices of blood lipids as well as liver enzymes. However, a considerable change was observed in the body fat percent that may be attributed to the exercise protocol.
    Science & Sports 11/2014; 30(3). DOI:10.1016/j.scispo.2014.09.002 · 0.33 Impact Factor
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