High-intensity interval training: optimizing oxygen consumption and time to exhaustion taking advantage of the exponential reconstitution behaviour of D’

Purpose: Accumulating the time near maximum aerobic power (V ˙ O 2max) is considered to be the most effective way to improve aerobic capacity. The aims of this study were: (1) to verify whether postponing the first recovery interval improves time to exhaustion during a high-intensity interval training (HIIT) test, and (2) to verify whether a HIIT protocol with decreasing interval duration (HIDIT) is more effective in accumulating time near V ˙ O 2max compared with two classical protocols with short intervals (SIHIIT) and long intervals (LIHIIT). Methods: Nine active males (35 ± 11 years, V ˙ O 2max 52 ± 5 mL·min−1·kg−1) performed a graded exercise test on an athletic track. Critical velocity and D’ were estimated from three to five high-intensity trials to exhaustion. Then, the subjects performed three trials with a single recovery interval after 30 s (Rec30s), after 3 min (Rec3min) and after exhaustion (RecTlim) to verify whether postponing the first recovery interval enhances the time to exhaustion. Finally, the subjects performed the three HIIT protocols mentioned above. Results: The time to exhaustion was significantly greater in RecTlim (464 ± 67 s) than in Rec3min (388 ± 48 s) (p 0.0001). Additionally, it was significantly greater in Rec3min than in Rec30s (p = 0.0247). Furthermore, the time accumulated near V ˙ O 2max was significantly longer in HIDIT (998 ± 129 s) than in SIHIIT (678 ± 116 s) (p = 0.003) and LIHIIT (673 ± 115 s) (p < 0.031). Conclusions: During the trials, postponing the first recovery interval was effective in improving the time to exhaustion. Moreover, HIDIT was effective in prolonging the time near V ˙ O 2max

Relationship between body mass index and physical fitness in Italian prepubertal schoolchildren

The objective of this study was to investigate the association between physical fitness and body mass index categories (obesity, OB; overweight, OW; normal-weight, NW; and underweight, UW) in prepubertal children. Anthropometric and physical fitness characteristics were collected from a convenience sample of 30472 Italian schoolchildren (6\u201311 years old). Six field-based tests were used: L\ue9ger, agility shuttle, long jump, frontal throw of the basketball, Sit & Reach and standing balance. Significant differences were found in the anthropometric characteristics, physical fitness and weight status prevalence between girls and boys (p<0.05) and, except for flexibility, by age class (p<0.05). Obese children performed worse than their NW counterparts in aerobic capacity (p<0.001), agility (p<0.001), muscular power of the lower limb (p<0.001) and balance (p<0.001). Conversely, children with obesity showed greater upper limb power than NW children (p<0.001). The discrepancy in physical fitness between OB and NW children increased in older girls (flexibility, p = 0.002; muscular power of the lower and upper limb, p = 0.002 and p = 0.005) and boys (aerobic capacity, p = 0.009; agility, p = 0.006; standing balance, p = 0.019; muscular power of the lower and upper limb, p<0.001 and p = 0.011) compared to their younger counterparts. On the other hand, UW children performed worse than NW children mainly in terms of muscular power of the arms (p<0.001). Additionally, there was an increasing disparity in the frontal throw test scores of UW and NW girls (p = 0.003) and boys (p = 0.011) in older children compared to younger children. In conclusion, the effect of body mass index on children\u2019s physical fitness intensifies with age. OB and OW negatively affect aerobic capacity, agility, lower limb power and balance but positively affect upper limb power. UW negatively affects upper limb power. This study underscores the importance of preventing childhood OW, OB, and UW in early life to promote children\u2019s health and proper fitness development

Corrigendum: Effects of a 3-week inpatient multidisciplinary body weight reduction program on body composition and physical capabilities in adolescents and adults with obesity

A correction has been made to Funding. The correct Funding statement is: “Research funded by the Italian Ministry of Health.” The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. The original article has been updated

Effects of combined training or moderate intensity continuous training during a 3-week multidisciplinary body weight reduction program on cardiorespiratory fitness, body composition, and substrate oxidation rate in adolescents with obesity

This study aimed to investigate the effects of combined training (COMB, a combination of moderate-intensity continuous training-MICT and high-intensity interval training-HIIT) vs. continuous MICT administered during a 3-week in-hospital body weight reduction program (BWRP) on body composition, physical capacities, and substrate oxidation in adolescents with obesity. The 3-week in-hospital BWRP entailed moderate energy restriction, nutritional education, psychological counseling, and two different protocols of physical exercise. Twenty-one male adolescents with obesity (mean age: 16.1 ± 1.5 years; mean body mass index [BMI] 37.8 ± 4.5 kg m−2) participated in this randomized control trial study (n:10 for COMB, n:11 MICT), attending ~ 30 training sessions. The COMB group performed 3 repetitions of 2 min at 95% of peak oxygen uptake (V′O2 peak) (e.g., HIIT ≤ 20%), followed by 30 min at 60% of V′O2 peak (e.g., MICT ≥ 80%). Body composition, V′O2 peak, basal metabolic rate (BMR), energy expenditure, and substrate oxidation rate were measured during the first week (W0) and at the end of three weeks of training (W3). The two training programs were equivalent in caloric expenditure. At W3, body mass (BM) and fat mass (FM) decreased significantly in both groups, although the decrease in BM was significantly greater in the MICT group than in the COMB group (BM: − 5.0 ± 1.2 vs. − 8.4 ± 1.5, P < 0.05; FM: − 4.3 ± 3.0 vs. − 4.2 ± 1.9 kg, P < 0.05). V′O2 peak increased only in the COMB by a mean of 0.28 ± 0.22 L min−1 (P < 0.05). The maximal fat oxidation rate (MFO) increased only in the COMB group by 0.04 ± 0.03 g min−1 (P < 0.05). COMB training represents a viable alternative to MICT for improving anthropometric characteristics, physical capacities, and MFO in adolescents with obesity during a 3-week in-hospital BWRP

Cardiometabolic Index (CMI) and Visceral Adiposity Index (VAI) Highlight a Higher Risk of Metabolic Syndrome in Women with Severe Obesity

Recent evidence shows that simple and inexpensive anthropometric measurements can be used to identify, at an early stage, women with obesity at increased risk of developing metabolic syndrome (MetS). Thus, the aim of this study was to compare the accuracy of five different indexes of adiposity and/or body composition in identifying MetS in a group of 876 women (mean age ± SD: 52.1 ± 13.8 years; body mass index (BMI): 43.6 ± 6.1 kg m−2). The following indexes were determined for each subject: waist-to-hip ratio (WHR), waist-to-height ratio (WtHR), body mass fat index (BMFI), visceral adiposity index (VAI), and cardiometabolic index (CMI). Overall, the presence of MetS was detected in 544 patients (62%). Pearson correlation coefficients were calculated to evaluate the relationships between body composition indexes and metabolic characteristics of the women. Receiver operating characteristic (ROC) analysis was used to determine the best predictor for each adiposity index among metabolic risk factors. The ROC analysis showed VAI (AUC = 0.84) and CMI (AUC = 0.86) showed the best performance in predicting MetS. Differences were found between the ROC area of CMI and VAI with all other indexes (p 0.92 for WHR, >0.76 for WtHR, >30.1 kg m−1 for BMFI, >1.94 for VAI, and >0.84 for CMI. In addition, VAI and CMI were the most sensitive and specific indexes compared with other indexes. In conclusion, VAI and CMI represent the most useful and reliable indexes to be used for detecting MetS in women suffering from obesity in clinical practice

Effects of 12-week combined training versus high intensity interval training on cardiorespiratory fitness, body composition and fat metabolism in obese male adults

Background: /Objectives: A weekly combination of a high volume of moderate-intensity continuous training (MICT) with a low volume of high-intensity interval training (HIIT) provides important improvements in body composition and physical capacities in individuals with obesity. However, previous studies did not determine the weekly proportions of HIIT and MICT a priori. This study aimed to investigate changes in body composition, physical capacities and the fat oxidation rate in obese male adults by comparing a combination of MICT and HIIT, called combined training (COMB), with HIIT for a 12-week period. Methods: Thirty-four obese male adults (mean age: 39.4 ± 7.0 y; mean body mass index [BMI] 34.0 ± 4.2 kg m−2) participated in this study (n = 18 for COMB, n = 16 HIIT), attending ∼ 36 training sessions. The COMB group performed 3 repetitions of 2 min at 95% of peak oxygen uptake (V'O2 peak) (e.g., HIIT ≤20%), followed by 30 min at 60% of VO2 peak (e.g., MICT ≥80%). The HIIT group performed 5–7 repetitions of 2 min at 95% of VO2 peak. At baseline (PRE) and at the end of the training period (POST), body composition, VO2 peak, and the fat oxidation rate were measured. The two training programs were equivalent in caloric expenditure. Results: At POST, body mass (BM) and fat mass (FM) decreased by a mean of 3.09 ± 3.21 kg and 3.90 ± 2.40 kg, respectively (P < 0.05), in both groups and V'O2 peak increased in both groups by a mean of 0.47 ± 0.34 L min−1 (P < 0.05). The maximal fat oxidation rate increased similarly in both groups from 0.32 ± 0.05 to 0.36 ± 0.06 g min−1 (P < 0.05). Conclusion: COMB training represents a viable alternative to HIIT to improve anthropometric characteristics, physical capacities and fat oxidation in obese male adults

The Effect of Endurance Training on Pulmonary V˙O2 Kinetics in Solid Organs Transplanted Recipients

BACKGROUND: We investigated the effects of single (SL-ET) and double leg (DL-ET) high-intensity interval training on O2 deficit (O2Def) and mean response time (MRT) during square-wave moderate-intensity exercise (DL-MOD), and on the amplitude of V˙O2p slow component (SCamp), during heavy intensity exercise (DL-HVY), on 33 patients (heart transplant = 13, kidney transplanted = 11 and liver transplanted = 9). METHODS: Patients performed DL incremental step exercise to exhaustion, two DL-MOD tests, and a DL-HVY trial before and after 24 sessions of SL-ET (n = 17) or DL-ET (n = 16). RESULTS: After SL-ET, O2Def, MRT and SCamp decreased by 16.4% ± 13.7 (p = 0.008), by 15.6% ± 13.7 (p = 0.004) and by 35% ± 31 (p = 0.002), respectively. After DL-ET, they dropped by 24.9% ± 16.2 (p &lt; 0.0001), by 25.9% ± 13.6 (p &lt; 0.0001) and by 38% ± 52 (p = 0.0003), respectively. The magnitude of improvement of O2Def, MRT, and SCamp was not significantly different between SL-ET and DL-ET after training. CONCLUSIONS: We conclude that SL-ET is as effective as DL-ET if we aim to improve V˙O2p kinetics in transplanted patients and suggest that the slower, V˙O2p kinetics is mainly caused by the impairment of peripherals exchanges likely due to the immunosuppressive medications and disuse

Skeletal Muscle Mitochondrial and Perilipin Content in a Cohort of Obese Subjects Undergoing Moderate and High Intensity Training

Obesity is a complex condition characterized by abnormal and excessive fat accumulation, resulting in an increased risk for severe health problems. Skeletal muscles play a major role in movement and fat catabolism, but the insulin resistance that comes with obesity makes it difficult to fulfill these tasks. In this study, we analyse two types of training protocols, moderate intensity continuous training (MICT) versus high intensity interval training (HIIT), in a cohort of obese subjects to establish which muscle adaptations favour fat consumption in response to exercise. Mitochondria play a role in fat oxidation. We found protein upregulation of mitochondrial biomarkers, TOMM20 and Cox-4, in HIIT but not in MICT, without detecting any shifts in fibre composition phenotype of the vastus lateralis in both training groups. Interestingly, both MICT and HIIT protocols showed increased protein levels of perilipin PLIN2, which is involved in the delivery and consumption of fats. HIIT also augmented perilipin PLIN5. Perilipins are involved in fat storage in skeletal muscles and their upregulation, along with the analysis of circulatory lipid profiles reported in the present study, suggest important adaptations induced by the two types of training protocols that favour fat consumption and weight loss in obese subjects

In Cardiac Patients β-Blockers Attenuate the Decrease in Work Rate during Exercise at a Constant Submaximal Heart Rate

Purpose Exercise prescription based on fixed heart rate (HR) values is not associated with a specific work rate (WR) during prolonged exercise. This phenomenon has never been evaluated in cardiac patients and might be associated with a slow component of HR kinetics and β-adrenergic activity. The aims were to quantify, in cardiac patients, the WR decrease at a fixed HR and to test if it would be attenuated by β-blockers. Methods Seventeen patients with coronary artery disease in stable conditions (69 ± 9 yr) were divided into two groups according to the presence (BB) or absence (no-BB) of a therapy with β-blockers, and performed on a cycle ergometer: An incremental exercise (INCR) and a 15-min "HRCLAMPED"exercise, in which WR was continuously adjusted to maintain a constant HR, corresponding to the gas exchange threshold +15%. HR was determined by the ECG signal, and pulmonary gas exchange was assessed breath-by-breath. Results During INCR, HRpeak was lower in BB versus no-BB (P < 0.05), whereas no differences were observed for other variables. During HRCLAMPED, the decrease in WR needed to maintain HR constant was less pronounced in BB versus no-BB (-16% ± 10% vs -27 ± 10, P = 0.04) and was accompanied by a decreased VO2 only in no-BB (-13% ± 6%, P < 0.001). Conclusions The decrease in WR during a 15-min exercise at a fixed HR (slightly higher than that at gas exchange threshold) was attenuated in BB, suggesting a potential role by β-adrenergic stimulation. The phenomenon may represent, also in this population, a sign of impaired exercise tolerance and interferes with aerobic exercise prescription

Effectiveness of high-intensity interval training for weight loss in adults with obesity: A randomised controlled non-inferiority trial

Introduction Obesity treatment guidelines suggest moderate-intensity continuous training (MICT), but the patient's compliance to this indication remains low. High-intensity interval training (HIIT) is a time sparing training mode whose metabolic effects are not clear. This study aimed to determine whether a 12-week HIIT was more effective than MICT for weight loss in obese adults. Methods 44 obese subjects were randomised and trained with isoenergetic treadmill exercises for 12 weeks: MICT (60% of maximal oxygen peak, VO 2 peak) or HIIT (3-7 repetition of 3 min 100% of VO 2 peak interspersed by 1.5 min 50% of VO 2 peak). The primary outcome was a change in body weight; the secondary outcomes were changes in body composition, blood pressure, lipid profile, glycaemia, insulin and VO 2 peak. Results 32 subjects (53% male, mean age: 38.5 years, mean body mass index: 35.5 kg/m 2) completed the trial. MICT and HIIT showed comparable effect within groups in weight loss (-6.0 kg (-9.0 kg to -3.0 kg) vs -5.7 kg (-8.3 kg to -3.1 kg)), changes in fat mass (-2.9% (-4.4% to -1.4%) vs -3.6% (-5.9% to -1.2%)), fat free mass (-5.3% (-7.8% to -2.8%) vs -5.5% (-8.3% to -2.6%)), diastolic blood pressure (-5.5 mm Hg (-10.6 mm Hg to -0.3 mm Hg) vs -5.8 mm Hg (-11.3 mm Hg to -0.3 mm Hg)) and low-density lipoprotein cholesterol (-16.4 mg/dL (-30.8 mg/dL to -2.0 mg/dL) vs -14.7 mg/dL (-25.6 mg/dL to -3.8 mg/dL)). There was a significant change between groups in VO 2 peak (HIIT: +461.6 mL (329.3a \u20ac'593.8 mL); MICT: +170.5 mL (86.7-254.4 mL); p<0001) and duration of sessions (HIIT: 35.0 min (31.7 a \u20ac'35.6 min); MICT: 46.5 min (40.2a \u20ac'48.3 min); p<0.001). No significant changes in systolic blood pressure, high-density lipoprotein cholesterol, triglycerides, glycaemia or plasma insulin were observed. Conclusions In healthy adults with obesity, HIIT compared with MICT induced similar weight loss and cardiovascular risk factors improvement but resulted in a larger increase in cardiorespiratory fitness over a shorter period