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Kong, Zhaowei, Qian Yu, Shengyan Sun, On Kei Lei, Yu Tian, Qingde Shi, Jinlei Nie, and Martin Burtscher. The impact of sprint interval exercise in acute severe hypoxia on executive function.

This study examined the effects of 12 weeks of sprint interval training (SIT), high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on cardiorespiratory fitness (peak oxygen uptake, VO

Objective: The purpose of this study was to investigate the effects of repeated sprint interval training (RSIT) under different hypoxic conditions in comparison with normoxic RSIT on cardiorespiratory fitness (CRF) and metabolic health in sedentary young women. Methods: Sixty-two sedentary young women (age: 21.9 ± 2.8 years, peak oxygen uptake [V̇O2peak] 25.9 ± 4.5 ml kg−1·min−1) were randomized into one of the four groups, including a normoxic RSIT group (N), RSIT simulating an altitude of 2500 m (H2500), RSIT simulating an incremental altitude of 2500–3400 m (H2500–3400) and a non-exercise control group (C). The training intervention (80 × 6 s all-out cycling sprints with 9 s recovery) was performed three times/week for 4 weeks. Anthropometric measures, V̇O2peak, fasting blood glucose and lipids were assessed during the follicular phase of the menstrual cycle before and after the intervention. Results: Compared with the control group, significant increases in V̇O2peak were found in both hypoxic groups (H2500: +8.2%, p 0.05, d = 0.21) after the intervention, whereas the two hypoxic groups had no difference in V̇O2peak. Blood glucose and lipids, and body composition remained unchanged in all groups. Conclusion: The present study indicates that combining hypoxia with RSIT can enhance the improvement of CRF compared with normoxic RSIT alone in the sedentary young population. Yet, compared with RSIT under stable hypoxia, incremental hypoxia stress in the short-term does not additionally ameliorate CRF.

The current study examined the factor structure, measurement reliability, measurement invariance across genders, and latent gender mean differences, of a new Chinese translation of the Adult Eating Behavior Questionnaire (C-AEBQ) in a Chinese young adult sample ( n = 1,068, 52.57% women). The associations between the appetitive traits assessed by the AEBQ and body mass index were also explored. The previously established eight-factor model of the AEBQ was supported in the present sample. The C-AEBQ had strong measurement invariance between genders. Cronbach’s alpha estimates of the eight subscales of the C-AEBQ ranged from 0.76 to 0.97, and the test–retest reliability coefficients of the subscales ranged from 0.50 to 0.77. The C-AEBQ had adequate convergent and divergent validity, as supported by the theoretically expected correlations between C-AEBQ and the Three-Factor Eating Questionnaire. Furthermore, Satiety Responsiveness, Slowness in Eating, and Food Fussiness were inversely associated with body mass index. Overall, the C-AEBQ appears to be a psychometrically sound instrument as a comprehensive measure for appetitive traits for Chinese young adults.

Objective: The purpose of this study was to evaluate the effects of a 4-week low-carbohydrate diet (LC) with or without exercise training on cardiometabolic health-related profiles in overweight/obese women. Methods: Fifty overweight/obese Chinese women (age: 22.2 ± 3.3 years, body mass index (BMI): 25.1 ± 3.1 kg·m−2) were randomized to either a LC control group (LC-CON, n = 16), a LC and high-intensity interval training group (LC-HIIT, n = 17), or a LC and moderate-intensity continuous training group (LC-MICT, n = 17). All groups consumed LC for 4 weeks, while the LC-HIIT and LC-MICT groups followed an additional five sessions of HIIT (10 × 6 s cycling sprints and 9 s rest intervals, 2.5 min in total) or MICT (cycling continuously at 50–60% of peak oxygen uptake (VO2peak) for 30 min) weekly. Blood pressure, fasting glucose, insulin sensitivity, and several metabolic or appetite regulating hormones were measured before and after intervention. Results: Significant reductions in body weight (− ~2.5 kg, p &lt, 0.001, η2 = 0.772) and BMI (− ~1 unit, p &lt, 0.001, η2 = 0.782) were found in all groups. Systolic blood pressure was reduced by 5–6 mmHg (p &lt, 0.001, η2 = 0.370), fasting insulin, leptin, and ghrelin levels were also significantly decreased (p &lt, 0.05), while insulin sensitivity was improved. However, there were no significant changes in fasting glucose, glucagon, and gastric inhibitory peptide levels. Furthermore, no group differences were found among the three groups, suggesting that extra training (i.e., LC-HIIT and LC-MICT) failed to trigger additional effects on these cardiometabolic profiles. Conclusions: The short-term carbohydrate restriction diet caused significant weight loss and improved blood pressure and insulin sensitivity in the overweight/obese women, although the combination with exercise training had no additional benefits on the examined cardiometabolic profiles. Moreover, the long-term safety and effectiveness of LC needs further study.

The purpose of this study was to examine the effects of a short-term ketogenic diet (KD) on body composition and cardiorespiratory fitness (CRF) in overweight/obese Chinese females. Twenty young females [age: 21.0 ± 3.7 years, weight: 65.5 ± 7.7 kg, body mass index (BMI): 24.9 ± 2.7 kg⋅m–2] consumed 4 weeks of a normal diet (ND) as a baseline and then switched to a low-carbohydrate, high-fat, and adequate protein KD for another 4 weeks. With the same daily caloric intake, the proportions of energy intake derived from carbohydrates, proteins, and fats were changed from 44.0 ± 7.6%, 15.4 ± 3.3%, 39.6 ± 5.8% in ND to 9.2 ± 4.8%, 21.9 ± 3.4%, and 69.0 ± 5.4% in KD. The results showed that, without impairing the CRF level, the 4-week KD intervention significantly reduced body weight (−2.9 kg), BMI (−1.1 kg⋅m–2), waist circumference (−4.0 cm), hip circumference (−2.5 cm), and body fat percentage (−2.0%). Moreover, fasting leptin level was lowered significantly, and serum levels of inflammatory markers (i.e., TNF-α and MCP-1) were unchanged following KD. These findings suggest that KD can be used as a rapid and effective approach to lose weight and reduce abdominal adiposity in overweight/obese Chinese females without exacerbating their CRF.

Low-carbohydrate diets (LCs) seem effective on weight reduction and maintenance. However, the affect and enjoyment of exercise during LCs is not clear. The purpose of the present study was to compare the psychological responses to high-intensity interval training (HIIT) and to moderate-intensity continuous training (MICT) during the consumption of a 4-week LC diet in overweight young women. With LCs (~10% carbohydrate, 65%&ndash, 70% fat, 20%&ndash, 25% protein), forty-three eligible women (age: 20.9 &plusmn, 3.1 years, body weight: 65.8 &plusmn, 8.2 kg) were randomly assigned to one of three groups: HIIT (10 sets of 6 s all-out cycling interspersed with 9 s of rest), MICT (30 min cycling at 50%&ndash, 60% of peak oxygen consumption, V̇O2peak) or no-exercise controls (CON). Anthropometric indices and V̇O2peak were measured pre- and post-training. Feeling Scale (FS), Felt Arousal Scale (FAS), Exercise Enjoyment Scale (EES), and Physical Activity Enjoyment Scale (PACES) scores were collected before and immediately after each training session throughout the study. After intervention, all three groups reduced by more than 2.5 kg of body weight whereas both exercise groups improved ~15% V̇O2peak. Participants in the HIIT and MICT group exhibited similar affect points as indicated by FS and FAS. Post-exercise enjoyment scores in PACES were lower in HIIT (73&ndash, 78 points) than MICT (83&ndash, 87 points) despite similarly positive responses being observed in EES (corresponding to ~4 points of a 7-point scale). Short-term LCs were effective in weight loss and exercise training had an additive improvement on cardiorespiratory fitness. The overweight young women had similar affect valence, arousal levels, and comparable pleasurable feelings to HIIT and MICT with LCs. Furthermore, as indicated by PACES, MICT was more enjoyable which may elicit better adherence, whereas HIIT with LCs seems to be more arduous despite its time-efficiency.

Background/Objective: This study examined whether time spent at high rates of oxygen consumption (VO2) during 6-s sprint interval exercises (SIE) is a function of recovery interval duration. Methods: In a randomised crossover study, thirteen male endurance runners performed 40 × 6-s all-out sprints interspersed with 15-s, 30-s and 60-s passive recovery intervals (SIE15, SIE30, and SIE60 trials respectively), and a work duration-matched Wingate-SIE (8 × 30-s all-out sprints with 4-min passive recovery, SIEWin trial). The accumulated exercise time at ≥ 80%, 85%, 90%, 95% and 100% of VO2max, and maximum heart rate (HRmax) in the four trials were compared. Results: During the 6-s SIEs, accumulated time spent at all selected high rates of VO2max increased as recovery time decreased, whilst the SIE work rate decreased (p .05), and longer than that in SIE60 (20 ± 14 s, p

Benefits of performing sprint interval training (SIT) under hypoxic conditions on improving cardiorespiratory fitness and body composition have been well-documented, yet data is still lacking regarding affective responses to SIT under hypoxia. This study aimed to compare affective responses to SIT exercise under different oxygen conditions. Nineteen active males participated in three sessions of acute SIT exercise (20 repetitions of 6 s of all-out cycling bouts interspersed with 15 s of passive recovery) under conditions of normobaric normoxia (SL: PIO2 150 mmHg, FIO2 0.209), moderate hypoxia (MH: PIO2 117 mmHg, FIO2 0.154, simulating an altitude corresponding to 2500 m), and severe hypoxia (SH: PIO2 87 mmHg, FIO2 0.112, simulating an altitude of 5000 m) in a randomized order. Perceived exertions (RPE), affect, activation, and enjoyment responses were recorded before and immediately after each SIT session. There were no significant differences across the three conditions in RPE or the measurements of affective responses, despite a statistically lower SpO2 (%) in severe hypoxia. Participants maintained a positive affect valence and reported increased activation in all the three SIT conditions. Additionally, participants experienced a medium level of enjoyment after exercise as indicated by the exercise enjoyment scale (EES) and physical activity enjoyment scale (PACES). These results indicated that performing short duration SIT exercise under severe hypoxia could be perceived as pleasurable and enjoyable as performing it under normoxia in active male population.

This study aimed to examine the effects of four weeks of a low-carbohydrate diet (LC) and incorporated exercise training on body composition and cardiometabolic health. Fifty-eight overweight/obese Chinese females (age: 21.2 &plusmn, 3.3 years, body mass index (BMI): 25.1 &plusmn, 2.8 kg/m2) were randomly assigned to the control group (CON, n = 15), the LC control group (LC-CON, n = 15), the LC and high-intensity interval training group (LC-HIIT, n = 15), or the LC and moderate-intensity continuous training group (LC-MICT, n = 13). Subjects consumed a four week LC, whereas LC-HIIT and LC-MICT received extra training 5 d/week (LC-HIIT: 10 &times, 6 s cycling interspersed with 9 s rest, MICT: 30 min continuous cycling at 50&ndash, 60% VO2peak). After intervention, the three LC groups demonstrated significant reductions in body weight (&minus, 2.85 kg in LC-CON, &minus, 2.85 kg in LC-HIIT, &minus, 2.56 kg in LC-MICT, p &lt, 0.001, &eta, 2 = 0.510), BMI (p &lt, 2 = 0.504) and waist-to-hip ratio (p &lt, 2 = 0.523). Groups with extra training (i.e., LC-HIIT and LC-MICT) improved VO2peak by 14.8 and 17.3%, respectively. However, fasting glucose and blood lipid levels remained unchanged in all groups. Short-term LC is a useful approach to improve body composition in overweight/obese Chinese females. Incorporated exercise training has no additional effects on weight loss, but has additional benefits on cardiorespiratory fitness, and HIIT is more time efficient than the traditional MICT (2.5 min vs. 30 min).

Background: The improvement of living standards has led to increases in the prevalence of hypokinetic diseases. In particular, multifactorial complex diseases, such as metabolic syndrome, are becoming more prevalent. Currently, developing effective methods to combat or prevent metabolic syndrome is of critical public health importance. Thus, we conducted a systematic review to evaluate the existing literature regarding the effects of Wuqinxi exercise on reducing risk factors related to metabolic syndrome. Methods: Both English- and Chinese-language databases were searched for randomized controlled trials investigating the effects of Wuqinxi on these outcomes. Meanwhile, we extracted usable data for computing pooled effect size estimates, along with the random-effects model. Results: The synthesized results showed positive effects of Wuqinxi exercise on systolic blood pressure (SBP, SMD = 0.62, 95% CI 0.38 to 0.85, p < 0.001, I2 = 24.06%), diastolic blood pressure (DBP, SMD = 0.62, 95% CI 0.22 to 1.00, p < 0.001, I2 = 61.28%), total plasma cholesterol (TC, SMD = 0.88, 95% CI 0.41 to 1.36, p < 0.001, I2 = 78.71%), triglyceride (TG, SMD = 0.87, 95% CI 0.49 to 1.24, p < 0.001, I2 = 67.22%), low-density lipoprotein cholesterol (LDL-C, SMD = 1.24, 95% CI 0.76 to 1.72, p < 0.001, I2 = 78.27%), and high-density lipoprotein cholesterol (HDL, SMD = 0.95, 95% CI 0.43 to 1.46, p < 0.001, I2 = 82.27%). In addition, regression results showed that longer-duration Wuqinxi intervention significantly improved DBP (β = 0.00016, Q = 5.72, df = 1, p = 0.02), TC (β = −0.00010, Q = 9.03, df = 1, p = 0.01), TG (β = 0.00012, Q = 6.23, df = 1, p = 0.01), and LDL (β = 0.00011, Q = 5.52, df = 1, p = 0.02). Conclusions: Wuqinxi may be an effective intervention to alleviate the cardiovascular disease risk factors of metabolic syndrome.

This study compared the effects of 12-week sprint interval training (SIT), high-intensity interval training (HIIT), and moderate-intensity continuous training (MICT) on cardiorespiratory fitness (VO2peak), body mass and insulin sensitivity in overweight females. Forty-two overweight women (age 21.2 ± 1.4 years, BMI 26.3 ± 2.5 kg·m-2) were randomized to the groups of SIT (80 × 6-s sprints + 9-s rest), and isoenergetic (300KJ) HIIT (~9 × 4-min cycling at 90% VO2peak + 3-min rest) and MICT (cycling at 60% VO2peak for ~ 61-min). Training intervention was performed 3 d·week-1 for 12 weeks. After intervention, all three groups induced the same improvement in VO2peak (~ +25%, p < 0.001) and a similar reduction in body mass (~ - 5%, p < 0.001). Insulin sensitivity and fasting insulin levels were improved significantly on post-training measures in SIT and HIIT by ~26% and ~39% (p < 0.01), respectively, but remain unchanged in MICT. In contrast, fasting glucose levels were only reduced with MICT (p < 0.01). The three training strategies are equally effective in improving VO2peak and reducing body mass, however, the SIT is time-efficient. High-intensity training (i.e. SIT and HIIT) seems to be more beneficial than MICT in improving insulin sensitivity. Abbreviations: BMI: body mass index; CVD: cardiovascular disease; HIEG: hyperinsulinaemic euglycaemic glucose; HIIT: high-intensity interval training; HOMA-IR: homeostasis model assessment of insulin resistance; HR: heart rate; MICT: moderate-intensity continuous training; RPE: ratings of perceived exertion; SIT: sprint interval training; T2D: type 2 diabetes; VO2peak: peak oxygen consumption.

To compare postprandial glucose responses to high-intensity interval exercise (HIE) between obese and lean individuals.Thirty healthy young adult males (15 obese, 15 lean) ate a standardised meal, then performed HIE (4 × 30-s Wingate cycling/4-min rest) or a no-exercise control trial (CON). Blood glucose was measured preprandially and up to 150 min postprandially.Compared to CON, HIE reduced postprandial glucose concentrations at 120-150 min in obese (p 0.001) and lean men (p 0.05), with greater reductions in obese than lean subjects at 120 (-27.0% vs. -8.3%), 135 (-31.9% vs. -15.7%), and 150 min (-21.8% vs. -10.6%). The total glucose area under the curve (AUC) for the testing period was lower with HIE than CON among obese men (p 0.05), but not lean men (p 0.05). We found moderate correlations between body mass and postprandial glucose changes (r = 0.39-0.44, p 0.05), and between glucose AUC and body mass and fat free mass (r = 0.39-0.48, p 0.05).Our findings suggest that HIE may act as a time-efficient lifestyle intervention strategy for improving obesity-related diabetes risk factors, and might play a role in primary diabetes prevention for the healthy but sedentary population.

Purpose: To examine the effect of acute moderate-intensity continuous exercise performed under normobaric severe hypoxia on cognition, compared to sea-level normoxia. Methods: Thirty healthy inactive women randomly performed two experimental trials separated by at least three days but at approximately the same time of day. Executive functions were measured during the follicular stage via an interference control task before (rest) and during exercise with 45% peak power output under normobaric normoxia (PIO2 = 150 mmHg, FIO2 = 0.21), and (2) hypoxia (PIO2 = 87 mmHg, FIO2 = 0.12, simulated at an altitude of 4000 m). Reaction time (RT), accuracy rate (AC), heart rate, ratings of perceived exertion, and peripheral oxygen saturation (SpO2) were collected before and during exercise. Results: RT (p &lt, 0.05, &eta, 2p = 0.203) decreased during moderate exercise when compared at rest, while a short bout of severe hypoxia improved RT (p &lt, 2p = 0.134). Exercise and hypoxia had no effects on AC (p &gt, 0.05). No significant associations were found between the changes of RT and SpO2 under the conditions of normoxia and hypoxia (p &gt, 0.05). Conclusions: At the same phase of the menstrual cycle, a short bout of severe hypoxia simulated at 4000 m altitude caused no impairment at rest. RT during moderate exercise ameliorated in normoxia and severe hypoxia, suggesting that both exercise and short-term severe hypoxia have benefits on cognitive function in sedentary young women.

Background and Objectives: Limited research has evaluated the effects of acute exercise on cognition under different conditions of inspired oxygenation. Thus, the purpose of this study was to examine the effects of high-intensity interval exercise (HIE) under normoxia (inspired fraction of oxygen (FIO2): 0.209) and moderate hypoxia (FIO2: 0.154) on cognitive function. Design: A single-blinded cross-over design was used to observe the main effects of exercise and oxygen level, and interaction effects on cognitive task performance. Methods: Twenty inactive adults (10 males and 10 females, 19&ndash, 27 years old) performed a cognitive task (i.e., the Go/No-Go task) before and immediately after an acute bout of HIE under normoxic and hypoxic conditions. The HIE comprised 10 repetitions of 6 s high-intensity cycling against 7.5% body weight interspersed with 30 s passive recovery. Heart rate, peripheral oxygen saturation (SpO2) and rating of perceived exertion were monitored. Results: The acute bout of HIE did not affect the reaction time (p = 0.204, &eta, 2 = 0.083) but the accuracy rate decreased significantly after HIE under both normoxic and hypoxic conditions (p = 0.001, &eta, 2 = 0.467). Moreover, moderate hypoxia had no influence either on reaction time (p = 0.782, &eta, 2 = 0.004) or response accuracy (p = 0.972, &eta, 2 &lt, 0.001). Conclusions: These results indicate that an acute session of HIE may impair response accuracy immediately post-HIE, without sacrificing reaction time. Meanwhile moderate hypoxia was found to have no adverse effect on cognitive function in inactive young adults, at least in the present study.

This study was to determine the effects of five-week high-intensity interval training (HIIT) on cardiorespiratory fitness, body composition, blood glucose, and relevant systemic hormones when compared to moderate-intensity continuous training (MICT) in overweight and obese young women.Methods. Eighteen subjects completed 20 sessions of HIIT or MICT for five weeks. HIIT involved 60 × 8 s cycling at ~90% of peak oxygen consumption (V˙O2peak) interspersed with 12 s recovery, whereas MICT involved 40-minute continuous cycling at 65% ofV˙O2peak.V˙O2peak, body composition, blood glucose, and fasting serum hormones, including leptin, growth hormone, testosterone, cortisol, and fibroblast growth factor 21, were measured before and after training.Results. Both exercise groups achieved significant improvements inV˙O2peak(+7.9% in HIIT versus +11.7% in MICT) and peak power output (+13.8% in HIIT versus +21.9% in MICT) despite no training effects on body composition or the relevant systemic hormones. Blood glucose tended to be decreased after the intervention (p=0.062). The rating of perceived exertion in MICT was higher than that in HIIT (p=0.042).Conclusion. Compared with MICT, short-term HIIT is more time-efficient and is perceived as being easier for improving cardiorespiratory fitness and fasting blood glucose for overweight and obese young women.

The aim of this study was to compare the effects of 5-week high-intensity interval training (HIIT) and moderate-to-vigorous intensity continuous training (MVCT) on cardiometabolic health outcomes and enjoyment of exercise in obese young women.A randomized controlled experiment was conducted that involved thirty-one obese females (age range of 18-30) randomly assigned to either HIIT or MVCT five-week training programs. Participants in HIIT condition performed 20 min of repeated 8 s cycling interspersed with 12 s rest intervals, and those in MVCT condition cycled continuously for 40 min at 60-80% of peak oxygen consumption ([Formula: see text]O2peak), both for four days in a week. Outcomes such as [Formula: see text]O2peak, body composition estimated by bioimpedance analysis, blood lipids, and serum sexual hormones were measured at pre-and post-training. The scores of Physical Activity Enjoyment Scale (PAES) were collected during the intervention.After training, [Formula: see text]O2peak increased significantly for both training programs (9.1% in HIIT and 10.3% in MVCT) (p = 0.010, η2 = 0.41). Although MVCT group had a significant reduction in total body weight (TBW, -1.8%, p = 0.034), fat mass (FM, - 4.7%, p = 0.002) and percentage body fat (PBF, -2.9%, p = 0.016), there were no significant between-group differences in the change of the pre- and post-measures of these variables. The HIIT group had a higher score on PAES than the MVCT group during the intervention. For both conditions, exercise training led to a decline in resting testosterone and estradiol levels, but had no significant effect on blood lipids.Both HIIT and MVCT are effective in improving cardiorespiratory fitness and in reducing sexual hormones in obese young women; however, HIIT is a more enjoyable and time-efficient strategy. The mild-HIIT protocol seems to be useful for at least maintaining the body weight among sedentary individuals.