Efficacy Of High-intensity Interval Training Research Articles

High-Intensity Interval Training Mitigates Sarcopenia and Suppresses the Myoblast Senescence Regulator EEF1E1.

The optimal exercise regimen for alleviating sarcopenia remains uncertain. This study aimed to investigate the efficacy of high-intensity interval training (HIIT) over moderate-intensity continuous training (MICT) in ameliorating sarcopenia. We conducted a randomized crossover trial to evaluate plasma proteomic reactions to acute HIIT (four 4-min high-intensity intervals at 70% maximal capacity alternating with 4 min at 30%) versus MICT (constant 50% maximal capacity) in inactive adults. We explored the relationship between a HIIT-specific protein relative to MICT, identified via comparative proteomic analysis, eukaryotic translation elongation factor 1 epsilon 1 (EEF1E1) and sarcopenia in a paired case-control study of elderly individuals (aged over 65). Young (3 months old) and aged (20 months old) mice were randomized to sedentary, HIIT and MICT groups (five sessions/week for 4 weeks; n = 8 for each group). Measurements included skeletal muscle index, hand grip strength, expression of atrophic markers Atrogin1 and MuRF1 and differentiation markers MyoD, myogenin and MyHC-II via western blotting. We examined the impact of EEF1E1 siRNA and recombinant protein on D-galactose-induced myoblast senescence, measuring senescence-associated β-galactosidase and markers like p21 and p53. The crossover trial, including 10 sedentary adults (32 years old, IQR 31-32) demonstrated significant alterations in the abundance of 21 plasma proteins after HIIT compared with MICT. In the paired case-control study of 84 older adults (84 years old, IQR 69-81; 52% female), EEF1E1 was significantly increased in those with sarcopenia compared to those without (14.68 [95%CI, 2.02-27.34] pg/mL, p = 0.03) and was associated with skeletal muscle index (R2 = 0.51, p < 0.001) and hand grip strength (R2 = 0.54, p < 0.001). In the preclinical study, aged mice exhibited higher EEF1E1 mRNA and protein levels in skeletal muscle compared to young mice, accompanied by a lower muscle mass and strength, increased cellular senescence and protein degradation markers and reduced muscle differentiation efficiency (all p < 0.05). HIIT reduced EEF1E1 expression and mitigated age-related muscle decline and atrophy in aged mice more effectively than MICT. Notably, EEF1E1 downregulation via siRNA significantly counteracted D-galactose-induced myoblast senescence as evidenced by reduced markers of muscle protein degradation and improved muscle differentiation efficiency (all p < 0.05). Conversely, treatments that increased EEF1E1 levels accelerated the senescence process (p < 0.05). Further exploration indicated that the decrease in EEF1E1 was associated with increased SIRT1 level and enhanced autophagy. This study highlights the potential of HIIT as a promising approach to prevent and treat sarcopenia while also highlighting EEF1E1 as a potential intervention target.

Feasibility, safety, adherence and efficacy of high-intensity interval training and moderate-intensity continuous training on functionality and quality of life in COVID-19 (COVIDEX) survivors: Phase I randomized clinical trial

Feasibility, safety, adherence and efficacy of high-intensity interval training and moderate-intensity continuous training on functionality and quality of life in COVID-19 (COVIDEX) survivors: Phase I randomized clinical trial

Efficacy of high-intensity interval training versus continuous training on serum myonectin and lipid outcomes in adults with metabolic syndrome: A post-hoc analysis of a clinical trial.

Myonectin is a myokine with potential effects on the lipid metabolism; however, its regulation by exercise in humans remains unclear. We aimed to compare the efficacy of high-intensity interval training low-volume (HIIT) versus moderate-intensity continuous training (MICT) on serum myonectin, serum lipids, appendicular fat and lean mass, and intramuscular lipids in humans. Secondary analysis of a controlled, randomized, clinical trial in adults of both sexes with metabolic syndrome, who underwent a supervised, three-times/week, 12-week treadmill program. HIIT (n = 29) consisted of six intervals with one-minute, high-intensity phases at 90% of peak oxygen consumption (VO2peak) for a total of 22 min. MICT (n = 31) trained at 60% of VO2peak for 36 min. Serum myonectin was measured using a human enzyme-linked immunosorbent assay. Lipid profile was determined by enzymatic methods and free fatty acids (FFA) were measured by gas chromatography. Fat and lean mass were assessed by dual-energy X-ray absorptiometry. Intramuscular lipids were measured through proton magnetic resonance spectroscopy. Subjects had a mean age of 50.8±6.0 years and body mass index of 30.6±4.0 kg/m2. Compared to MICT, HIIT was not superior at increasing serum myonectin (p = 0.661) or linoleic acid (p = 0.263), reducing palmitic (p = 0.286) or stearic acid (p = 0.350), or improving lipid profile (all p>0.05), appendicular fat mass index -AFMI- (p = 0.713) or appendicular lean mass percentage -ALM- (p = 0.810). Compared to baseline, only HIIT significantly increased myonectin (p = 0.042), with a large effect size, although both interventions reduced AFMI and increased ALM with a large effect size. Lipid profile, FFA and intramuscular lipids did not change in any intervention group (p>0.05). Compared to MICT, HIIT low volume did not demonstrate superiority in improving serum lipids. The fact that both training types reduced AFMI without paralleled significant changes in serum myonectin suggests that this myokine may have a minor effect on short-middle-term exercise-induced fat mobilization.

Comparison of high-intensity interval training versus moderate-intensity continuous training in pulmonary rehabilitation for interstitial lung disease: a randomised controlled pilot feasibility trial

ObjectivesThis study aimed to investigate the feasibility and efficacy of high-intensity interval training (HIIT) compared with moderate-intensity continuous training (MICT) in pulmonary rehabilitation (PR) for people with interstitial lung disease...

Effects of high-intensity interval training on physical morphology, cardiorespiratoryfitness and metabolic risk factors of cardiovascular disease in children and adolescents: A systematic review and meta-analysis.

To systematically evaluate the safety and efficacy of high-intensity interval training in children and adolescents. Eight databases were searched. Descriptive analysis of the efficacy and safety of high-intensity interval training on body shape, cardiorespiratory fitness, and metabolic risk markers of cardiovascular disease in children and adolescents. Subgroup analysis was performed using age, participants, intervention time, and exercise frequency as covariates. 47 studies included 2995 children and adolescents. The results of the meta-analysis showed that high-intensity interval training significantly improved cardiorespiratory fitness indicators (VO2max, SBP, DBP and HRmax) and cardiovascular disease biomarkers (TC and HDL-C). HIIT had no significant effect on body shape indicators (BMI, BF% and WC) or cardiovascular disease biomarkers (TG and LDL-C). Currently, there is insufficient evidence that HIIT with interval running as the predominant form improves physical indicators in children and adolescents. However, HIIT can be promoted in children and adolescents to improve cardiorespiratory fitness and reduce some metabolic risk of cardiovascular disease.

The Effect of High-Intensity Interval Training on Exercise Capacity in Patients with Coronary Artery Disease: A Systematic Review and Meta-Analysis.

The optimal exercise prescription for coronary artery disease (CAD) remains under debate. The aim of our meta-analysis is to investigate the efficacy of high-intensity interval training (HIIT) versus moderate-intensity continuous training (MICT) of coronary artery disease patients. Electronic databases were searched from their inception date until October 23, 2021, and the articles include randomized controlled trials. The mean differences and 95% confidence intervals were calculated, and heterogeneity was assessed using the I 2 test. The study standards were met by seventeen studies. The pooled studies included 902 patients. HIIT resulted in improvement in peak oxygen uptake (1.50 ml/kg/min, 95% confidence interval: 0.48 to 2.53, n = 853 patients, and low quality evidence) compared with MICT. There was no discernible difference between the individuals in the HIIT group and the MICT group in terms of systolic/diastolic blood pressure or peak/resting heart rate. This systematic review and meta-analysis reported the superiority of HIIT versus MICT in enhancing peak oxygen uptake in CAD patients.

Efficacy of high-intensity interval training for improving mental health and health-related quality of life in women with polycystic ovary syndrome

Women with PCOS have substantially greater symptoms of depression and anxiety, and a lower health-related quality of life (HRQoL) compared to women without PCOS. The aim of this study was to determine if high-intensity interval training (HIIT) could provide greater improvements in mental health outcomes than standard moderate-intensity continuous training (MICT). Twenty-nine overweight women with PCOS aged 18–45 years were randomly assigned to 12 weeks of either MICT (60–75% HRpeak, N = 15) or HIIT (> 90% HRpeak, N = 14). Outcome measures included symptoms of depression, anxiety and stress (DASS-21), general HRQoL (SF-36) and PCOS specific HRQoL (PCOSQ) collected at baseline and post-intervention. Reductions in depression (Δ − 1.7, P = 0.005), anxiety (Δ − 3.4, P < 0.001) and stress (Δ − 2.4, P = 0.003) scores were observed in the HIIT group, while MICT only resulted in a reduction in stress scores (Δ − 2.9, P = 0.001). Reductions in anxiety scores were significantly higher in the HIIT group compared to the MICT group (β = − 2.24, P = 0.020). Both HIIT and MICT significantly improved multiple domain scores from the SF-36 and PCOSQ. This study highlights the potential of HIIT for improving mental health and HRQoL in overweight women with PCOS. HIIT may be a viable strategy to reduce symptoms of depression and anxiety in women with PCOS, however, large-scale studies are required to confirm these findings.Trial registration number: ACTRN12615000242527.

Feasibility and acceptability of high-intensity interval training and moderate-intensity continuous training in kidney transplant recipients: the PACE-KD study

BackgroundKidney transplant recipients (KTRs) exhibit unique elevated inflammation, impaired immune function, and increased cardiovascular risk. Although exercise reduces cardiovascular risk, there is limited research on this population, particularly surrounding novel high-intensity interval training (HIIT). The purpose of this pilot study was to determine the feasibility and acceptability of HIIT in KTRs.MethodsTwenty KTRs (male 14; eGFR 58±19 mL/min/1.73 m2; age 49±11 years) were randomised and completed one of three trials: HIIT A (4-, 2-, and 1-min intervals; 80–90% watts at V̇O2peak), HIITB (4×4 min intervals; 80–90% V̇O2peak) or MICT (~40 min; 50–60% V̇O2peak) for 24 supervised sessions on a stationary bike (approx. 3x/week over 8 weeks) and followed up for 3 months. Feasibility was assessed by recruitment, retention, and intervention acceptability and adherence.ResultsTwenty participants completed the intervention, and 8 of whom achieved the required intensity based on power output (HIIT A, 0/6 [0%]; HIITB, 3/8 [38%]; MICT, 5/6 [83%]). Participants completed 92% of the 24 sessions with 105 cancelled and rescheduled sessions and an average of 10 weeks to complete the intervention. Pre-intervention versus post-intervention V̇O2peak (mL/kg-1/min-1) was 24.28±4.91 versus 27.06±4.82 in HIITA, 24.65±7.67 versus 27.48±8.23 in HIIT B, and 29.33±9.04 versus 33.05±9.90 in MICT. No adverse events were reported.ConclusionsThis is the first study to report the feasibility of HIIT in KTRs. Although participants struggled to achieve the required intensity (power), this study highlights the potential that exercise has to reduce cardiovascular risk in KTRs. HIIT and MICT performed on a cycle, with some modification, could be considered safe and feasible in KTRs. Larger scale trials are required to assess the efficacy of HIIT in KTRs and in particular identify the most appropriate intensities, recovery periods, and session duration. Some flexibility in delivery, such as incorporating home-based sessions, may need to be considered to improve recruitment and retention.Trial registrationISRCTN, ISRCTN17122775. Registered on 30 January 2017.

Effects of high-intensity interval training and strength training on levels of testosterone and physical activity among women with polycystic ovary syndrome.

ObjectivePolycystic ovary syndrome is a diverse endocrine disorder characterized by hyperandrogenism and ovulatory dysfunction. Hyperandrogenism affects body morphology, resulting in excess weight (overweight or obesity). This study aimed to evaluate the efficacy of high-intensity interval training on serum testosterone levels, body fat percentage, and level of physical activity among women with polycystic ovary syndrome.MethodsFifty participants were enrolled in the study and randomly allocated into two groups. Group A performed high-intensity interval training on alternate days per week (total of 12 weeks) and group B performed strength training on alternate days per week (total of 12 weeks). Baseline and 12th-week assessments included serum testosterone levels, body fat percentage using the skinfold method, and level of physical activity assessed using the International Physical Activity Questionnaire.ResultsAfter 12 weeks of intervention, both groups showed significant improvements in all the outcomes. However, group A (high intensity interval training) showed statistically significant results compared to group B (strength training) in lowering serum testosterone levels (P=0.049) and body fat percentage (P=0.001) and increasing physical activity levels (P=0.006).ConclusionAfter 12 weeks of exercise, both exercises benefited the participants; however, high-intensity interval training specifically was found to be a more effective exercise regimen than strength training in reducing serum testosterone levels and body fat percentage and enhancing levels of physical activity in women with polycystic ovary syndrome.

Acute effects of physical exercise on cognitive and psychological functioning in college students with attention-deficit/hyperactivity disorder

We sought to elucidate the acute effects of high-intensity interval training (HIIT) among college students with and without attention-deficit/hyperactivity disorder (ADHD). Participants were age- and sex-matched across ADHD (n = 18) and non-ADHD groups (n = 18) and both groups completed baseline (non-HIIT) and experimental sessions (HIIT). We examined within- and between-subject effects on a continuous performance task (CPT) and self-reported ADHD and internalizing symptomatology. We found that the degree of improvement on ADHD and depressive symptomatology, as well as processing speed and response variability following HIIT was significantly greater for the ADHD group than the comparison group. Further investigations such as randomized controlled trials focusing on the chronic effects of sustained HIIT interventions are needed to substantiate the potential feasibility and efficacy of HIIT as an intervention. HIIT may be a useful adjunct to psychosocial and/or pharmacological treatments for college students with ADHD because it: (a) yields immediate, acute improvements in executive functioning, ADHD, and mood; (b) promotes improved physical and mental health; (c) poses a relatively low risk of deleterious effects in apparently healthy college students. Even with the need for additional research, current data suggest a single, brief, high-intensity bout of aerobic exercise can yield immediate significant short-term improvements. These improvements may enhance functioning and improve outcomes for college students with ADHD.

Effect of High-Intensity Interval Training on Physical Health in Coronary Artery Disease Patients: A Meta-Analysis of Randomized Controlled Trials.

The effects of exercise-based cardiac rehabilitation (CR) on physical health in coronary artery disease (CAD) patients has long been established, while the optimal exercise mode remains to be determined. This meta-analysis compared the efficacy of high-intensity interval training (HIIT) versus moderate-intensity continuous training (MICT) in CAD patients. Databases were searched up to December 2020. Twenty-five studies with 1272 participants were analyzed. The results showed that both HIIT and MICT induced significant VO2peak improvement with a 4.52 mL/kg/min (p < 0.01) and 2.36 mL/kg/min (p < 0.01), respectively. Additionally, a larger improvement of VO2peak (1.92 mL/kg/min, p < 0.01) was observed in HIIT over MICT. HIIT with medium and long intervals, higher work/rest ratio induced larger VO2peak improvement than the compared subgroup. Interestingly, non-isocaloric exercise protocols induced larger VO2peak improvement compared with isocaloric protocols. In addition, both HIIT and MICT significantly increased anaerobic threshold and peak power with HIIT superior to MICT. No significant different changes were observed in blood pressure after HIIT or MICT intervention, however when HIIT was compared with MICT, MICT seems superior to HIIT in reducing systolic blood pressure (−3.61 mmHg, p < 0.01) and diastolic blood pressure (−2.37 mmHg, p < 0.01). Although, HIIT and MICT induced significant improvement of most other parameters, like HRrest, HRpeak, left ventricular ejection fraction (LVEF), quality of life (QoL), no significant differences were noted between groups. This meta-analysis suggested that HIIT is superior to MICT in increasing VO2peak, anaerobic threshold, peak power in CAD patients. Additionally, the efficacy of HIIT over MICT in improving VO2peaks was influenced by HIIT intervals, work/rest ratio and total caloric consumption. Both HIIT and MICT did not significantly influence resting BP, however, MICT seemed to be more effective in reducing BP than HIIT. HIIT and MICT equally significantly influenced HRrest, HRpeak, HRR1min, OUES, LVEF%, QoL.

Efficacy of high-intensity interval training on cardiac autonomic modulation in cardiovascular diseases and lifestyle disorders: a systematic review and meta-analysis

The study aims to investigate the literature on the effect of high-intensity interval training (HIIT) on cardiac autonomic function in individuals with cardiovascular disease (CVD) and lifestyle disorders. We performed electronic database search from CENTRAL, WoS, Scopus, Pubmed, and PEDro up to 25th February 2021. Randomised control trials/quasi-experimental trials/cross-over trials that assessed the effects of HIIT with control/alternative treatment on cardiac autonomic control were included in this review. A total of 11 studies were included for qualitative analysis and among them, 8 were quantitatively analysed. A random-effect model of standardised mean difference (SMD) and mean difference of the respective outcome measures for cardiac autonomic control was determined. The findings of the qualitative analysis revealed the beneficial effects of HIIT on cardiac autonomic modulation. However, the majority of the studies had an unclear or high risk of bias for randomisation, concealment methods, and blinding of participants to the intervention that could have influenced the interpretation of the findings. The SMD revealed a significant effect of HIIT on standard deviation of N-N intervals (SDNN) (ms) [SMD: 0.40, 95% confidence interval (CI): -0.001 to 0.80, P=0.05], high frequency power (HF) (ms2) [0.46, 95% CI: 0.17 to 0.76, P=0.002], and ratio of low and high frequency power, (LF/HF) [-0.80, 95% CI: -1.27 to -0.33, P=0.0008]. In conclusion, HIIT may effectively modulate cardiac autonomic function by increasing parasympathetic dominance, sympathetic withdrawal, and sympathovagal balance in individuals with CVD and lifestyle disorders. The study has a PROSPERO registration number: CRD42021231225

Brief Exercise at Work (BE@Work): A Mixed-Methods Pilot Trial of a Workplace High-Intensity Interval Training Intervention.

Introduction: The efficacy of high-intensity interval training (HIIT) for improving markers of physical fitness and cardiometabolic health is promising. The workplace is one non-laboratory setting where the effectiveness of HIIT could be explored. The aim of this study was to undertake a mixed-methods exploratory pilot trial of a workplace HIIT intervention named Brief Exercise at Work (BE@Work).Methods: Fifty-four healthy employees (mean ± standard deviation [SD] age 46 ± 10 years) from two workplaces in Northeast England were allocated to 8 weeks of thrice-weekly workplace HIIT based on boxing, stair climbing and stepping, comprising 4–7 60 s high-intensity intervals interspersed with 75 s rest (n = 30), or a no-intervention control (n = 24). The primary outcome was the change SD of predicted maximal oxygen consumption (VO2max). Markers of physical fitness, cardiometabolic health and mental well-being were also measured at baseline and follow-up. Participant perceptions of the intervention were explored in post-intervention focus groups (n = 9).Results: Mean (±SD) session attendance was 82% (±15%). Mean peak heart rate across the intervention was 87% of age-predicted maximal heart rate with a within- and between-subject SD of 5.5% and 3.7%, respectively. The SD of changes in predicted VO2max was 6.6 mL·kg−1·min−1 across both groups, which can be used to inform sample size estimations for a future full trial. The control-adjusted mean increase (95% confidence interval) in predicted VO2max was 3.9 (−0.2 to 8.1) mL·kg−1·min−1, corresponding to a Cohen's D of 0.47. We also observed preliminary evidence of small to moderate effects in favour of the intervention group for non-dominant leg extensor muscle power, markers of health-related quality of life, well-being and perceived stress and small to moderate effects in favour of the controls in perceived pain, physical activity and high-density lipoprotein cholesterol. During HIIT, focus group participants reported physiological responses they perceived as unpleasant or tiring (e.g., breathlessness, local muscular fatigue), but also that they felt alert and energised afterwards.Conclusion: The findings of this exploratory pilot trial support the implementation of a definitive randomised controlled trial to quantify the effectiveness of a workplace HIIT intervention.

Training parameters and effects of high-intensity interval training in patients with spinal cord injury: a review of literature

Background Inactivity among patients with spinal cord injury causes further deterioration of cardiorespiratory function and muscle strength. A variety of exercise modes, including high-intensity interval training (HIIT), have been applied to this population to aid them in maintaining good physical and mental health. However, an extensive review of the training parameters and efficacy of HIIT in patients with spinal cord injury remains lacking. Objectives This review aims to summarize the training parameters and effects of HIIT on cardiorespiratory function, muscle architecture, and strength among patients with spinal cord injury. Methods All studies were identified from electronic databases from 2005 to 2020. All articles were reviewed, and data were extracted independently by two reviewers. Risk of bias was assessed using the NIH Quality Assessment Tool for Before-After (Pre-Post) Studies with No Control Group. The methodological quality of randomized control trial (RCT) studies was measured using the PEDro scale. Results A total of 305 studies were identified from all listed databases. After screening, twelve experimental studies comprising three case studies, six quasi-experimental, and three RCTs were selected. Four studies were rated as good, and two studies were rated as fair for the methodology quality of the quasi-experimental study. All three RCT studies scored 5/10 or higher on the PEDro scale. A wide range of training parameters were found for HIIT training. Improvement of VO2peak was reported in seven studies. Information on the effect of HIIT on muscle strength was limited and inconclusive. Conclusion Despite limited evidence, HIIT could be considered effective in improving cardiorespiratory fitness in patients with spinal cord injury. However, whether or not HIIT can significantly improve muscle strength among this population remains inconclusive because of insufficient quality evidence.

Comparison of training responses and performance adaptations in endurance-trained men and women performing high-intensity interval training

ABSTRACT The efficacy of high-intensity interval training (HIIT) to elicit physiological and performance adaptations in endurance athletes has been established in men and to a lesser extent in women. This study compared lactate threshold (LT2) and performance adaptations to HIIT between men and women. Nine male and eight female cyclists and triathletes completed trials to determine their LT2 and 40 km cycling performance before, and after 10 HIIT sessions. Each HIIT session consisted of 10 × 90 s at peak power output, separated by 60 s active recovery. Main effects showed that HIIT improved peak power output (p = 0.05; ES: 0.2); relative peak power output (W.kg−1; p = 0.04; ES: 0.3 and W.kg−0.32; p = 0.04; ES: 0.3); incremental time to fatigue (p = 0.01; ES: 0.4), time trial time (p < 0.001; ES: 0.7) and time trial power output (p < 0.001; ES: 0.7) equally in both sexes. Although LT2 power output explained 77% of the performance improvement in women, no variable explained the performance improvement in men, suggesting another mechanism(s) was involved. Although HIIT improved cycling performance in men and women, it might not be appropriate to evaluate the effectiveness of HIIT using the same variables for both sexes.

Short-term and Long-term Feasibility, Safety, and Efficacy of High-Intensity Interval Training in Cardiac Rehabilitation

High-intensity interval training (HIIT) is recognized as a potent stimulus for improving cardiorespiratory fitness (volume of oxygen consumption [VO2] peak) in patients with coronary artery disease (CAD). However, the feasibility, safety, and long-term effects of HIIT in this population are unclear. To compare HIIT with moderate-intensity continuous training (MICT) for feasibility, safety, adherence, and efficacy of improving VO2 peak in patients with CAD. In this single-center randomized clinical trial, participants underwent 4 weeks of supervised training in a private hospital cardiac rehabilitation program, with subsequent home-based training and follow-up over 12 months. A total of 96 participants with angiographically proven CAD aged 18 to 80 years were enrolled, and 93 participants were medically cleared for participation following a cardiopulmonary exercise test. Data were collected from May 2016 to December 2018, and data were analyzed from December 2018 to August 2019. A 4 × 4-minute HIIT program or a 40-minute MICT program (usual care). Patients completed 3 sessions per week (2 supervised and 1 home-based session) for 4 weeks and 3 home-based sessions per week thereafter for 48 weeks. The primary outcome was change in VO2 peak during the cardiopulmonary exercise test from baseline to 4 weeks. Further testing occurred at 3, 6, and 12 months. Secondary outcomes were feasibility, safety, adherence, cardiovascular risk factors, and quality of life. Of 93 randomized participants, 78 (84%) were male, the mean (SD) age was 65 (8) years, and 46 were randomized to HIIT and 47 to MICT. A total of 86 participants completed testing at 4 weeks for the primary outcome, including 43 in the HIIT group and 43 in the MICT group; 69 completed testing at 12 months for VO2 peak, including 32 in the HIIT group and 37 in the MICT group. After 4 weeks, HIIT improved VO2 peak by 10% compared with 4% in the MICT group (mean [SD] oxygen uptake: HIIT, 2.9 [3.4] mL/kg/min; MICT, 1.2 [3.4] mL/kg/min; P = .02). After 12 months, there were similar improvements from baseline between groups, with a 10% improvement in the HIIT group and a 7% improvement in the MICT group (mean [SD] oxygen uptake: HIIT, 2.9 [4.5] mL/kg/min; MICT, 1.8 [4.3] mL/kg/min; P = .30). Both groups had high feasibility scores and low rates of withdrawal due to serious adverse events (3 participants in the HIIT group and 1 participant in the MICT group). One event occurred following exercise (hypotension) in the HIIT group. Over 12 months, both home-based HIIT and MICT had low rates of adherence (HIIT, 18 of 34 [53%]; MICT, 15 of 37 [41%]; P = .35) compared with the supervised stage (HIIT, 39 of 44 [91%]; MICT, 39 of 43 [91%]; P > .99). In this randomized clinical trial, a 4-week HIIT program improved VO2 peak compared with MICT in patients with CAD attending cardiac rehabilitation. However, improvements in VO2 peak at 12 months were similar for both groups. HIIT was feasible and safe, with similar adherence to MICT over 12-month follow-up. These findings support inclusion of HIIT in cardiac rehabilitation programs as an adjunct or alternative modality to moderate-intensity exercise. Australian New Zealand Clinical Trials Registry Identifier: ACTRN12615001292561.

Feasibility And Preliminary Efficacy Of High-intensity Interval Training During Neaodjuvant Chemoradiotherapy For Rectal Cancer

PURPOSE: To assess the feasibility, safety, and preliminary efficacy of a supervised high-intensity interval training (HIIT) program in rectal cancer patients undergoing 5-6 weeks of neoadjuvant chemoradiotherapy (NACRT). METHODS: Thirty-six rectal cancer patients scheduled to receive NACRT followed by surgery were randomized to either exercise training (n=18) or usual care (n=18) in the Exercise During and After Rectal Cancer Treatment (EXERT) Trial in Edmonton, Alberta. Patients in the exercise group were asked to complete 3 supervised HIIT sessions/week for the duration of NACRT. Feasibility was determined by eligibility rate, recruitment rate, follow-up rate and exercise adherence. Safety was assessed by tracking serious adverse events related to exercise. The primary efficacy outcome was cardiorespiratory fitness (VO2 peak) assessed immediately post-NACRT by a graded exercise test. Secondary efficacy outcomes included functional fitness assessed by the Senior’s Fitness Test. RESULTS: From June 2017 to August 2019, 205 rectal cancer patients were screened, 131 (64%) were eligible, and 36 (27%) were recruited. Follow-up fitness testing post-NACRT was completed in 75% (exercise n=14; control n=13). Reasons for missed fitness testing were medical issues. Median attendance for the supervised HIIT sessions during NACRT was 82%. No serious adverse events were observed, however, 2 patients in the exercise group experienced musculoskeletal events which resulted in 4 missed exercise sessions. Analyses of covariance showed no statistically significant or clinically meaningful difference between groups for the primary outcome of VO2 peak (adjusted between-group mean difference, 0.9 ml/kg/min; 95% CI, -1.6, 3.3; p = 0.47). The 8-foot up-and-go was significantly better in the exercise group post-NACRT (adjusted between group mean difference, -0.4 seconds; 95% CI, -0.7, 0.0, p = 0.031). No other significant group differences in functional fitness were observed. CONCLUSIONS: Supervised HIIT during NACRT for rectal cancer was feasible and safe. Further research is needed, however, to better understand the feasibility of completing fitness testing immediately following NACRT and whether HIIT can produce meaningful improvements in fitness in this challenging clinical setting.

Viability of high intensity interval training in persons with spinal cord injury-a perspective review.

Spinal cord injury (SCI) leads to loss of sensory and motor function below the level of injury leading to paralysis and limitations to locomotion. Therefore, persons with SCI face various challenges in engaging in regular physical activity, which leads to a reduction in physical fitness, increases in body fat mass, and reduced physical and mental health status. Moderate intensity continuous training (MICT) is recommended to enhance physical fitness and overall health status in this population, but it is not always effective in promoting these benefits. High intensity interval training (HIIT) has been promoted as an alternative to MICT in individuals with SCI due to its documented efficacy in healthy able-bodied individuals as well as those with chronic disease. However, the body of knowledge concerning its application in this population is limited and mostly composed of studies with small and homogeneous samples. The aim of this review was to summarize the existing literature regarding the efficacy of HIIT on changes in health- and fitness-related outcomes in this population, denote potential adverse responses to HIIT, describe how participants perceive this modality of exercise training, and identify the overall feasibility of interval training in persons with SCI.

Time-efficient and computer-guided sprint interval exercise training for improving health in the workplace: a randomised mixed-methods feasibility study in office-based employees

BackgroundThe efficacy of high-intensity interval training (HIT) as a time-efficient exercise strategy for beneficially modifying risk factors for cardiovascular disease has repeatedly been demonstrated in controlled laboratory settings. However, the effectiveness of HIT in an unsupervised workplace setting has not been investigated. The objective of this study was to use mixed methods to investigate the feasibility, acceptability and effectiveness of a short-duration, high-intensity exercise intervention (REHIT) when applied unsupervised in a workplace setting.MethodsTwenty-five office-workers (mean ± SD age: 47 ± 9 y, BMI: 27.5 ± 4.4 kg·m− 2, V̇O2max: 28 ± 7 mL·kg− 1·min− 1) completed a 6-week REHIT intervention unsupervised in their workplace (n = 13, 6 men), or acted as a no-intervention control (n = 12, 6 men). The intervention consisted of 2 sessions/week of low-intensity (~ 25 W) cycling interspersed with 2 ‘all-out’ sprints, increasing in duration from 10 to 20 s per sprint over the 6 weeks (total time-commitment: 8:40 min per session). V̇O2max was assessed pre- and post-training, whilst questionnaire-based measures of exercise enjoyment, self-efficacy, and acceptability were completed post-training. Eight participants also completed post-intervention semi-structured interviews.ResultsV̇O2max significantly improved in the exercise group (2.25 ± 0.75 L·min− 1 vs. 2.42 ± 0.82 L·min− 1; + 7.4%) compared to the control group (2.22 ± 0.72 L·min− 1 vs. 2.17 ± 0.74 L·min− 1; − 2.3%; time*intervention interaction effect: p < 0.01). Participants considered the REHIT intervention acceptable and enjoyable (PACES: 89 ± 17 out of 119) and were confident in their ability to continue to perform REHIT (7.8 ± 1.2 out of 9). Qualitative data revealed that REHIT offered a time-efficient opportunity to exercise, that was perceived as achievable, and which encouraged highly valued post-exercise outcomes (e.g. progress towards health/fitness benefits).ConclusionsREHIT could be implemented as a feasible, effective and acceptable exercise intervention in a workplace setting, with a total time-commitment of < 20 min/week. Consideration of certain psycho-social factors and behaviour-change techniques may ensure adherence to the REHIT programme in the long term.Trial registrationThe study was registered on ClinicalTrials.gov on 07/05/2019 (registration: NCT03941145).

High-intensity interval training produces a significant improvement in fitness in less than 31 days before surgery for urological cancer: a randomised control trial

ObjectivesTo assess the efficacy of high-intensity interval training (HIIT) for improving cardiorespiratory fitness (CRF) in patients awaiting resection for urological malignancy within four weeks.Subjects/patients and methodsA randomised control trial of consecutive patients aged (>65 years) scheduled for major urological surgery in a large secondary referral centre in a UK hospital. The primary outcome is change in anaerobic threshold (VO2AT) following HIIT vs. standard care.ResultsForty patients were recruited (mean age 72 years, male (39): female (1)) with 34 completing the protocol. Intention to treat analysis showed significant improvements in anaerobic threshold (VO2AT; mean difference (MD) 2.26 ml/kg/min (95% CI 1.25–3.26)) following HIIT. Blood pressure (BP) also significantly reduced in following: HIIT (SBP: −8.2 mmHg (95% CI −16.09 to −0.29) and DBP: −6.47 mmHg (95% CI −12.56 to −0.38)). No reportable adverse safety events occurred during HIIT and all participants achieved >85% predicted maximum heart rate during sessions, with protocol adherence of 84%.ConclusionsHIIT can improve CRF and cardiovascular health, representing clinically meaningful and achievable pre-operative improvements. Larger randomised trials are required to investigate the efficacy of prehabilitation HIIT upon different cancer types, post-operative complications, socio-economic impact and long-term survival.