Association of Preoperative High-Intensity Interval Training With Cardiorespiratory Fitness and Postoperative Outcomes Among Adults Undergoing Major Surgery: A Systematic Review and Meta-Analysis.

Importance: Preoperative high-intensity interval training (HIIT) is associated with improved cardiorespiratory fitness (CRF) and may improve surgical outcomes. Objective: To summarize data from studies comparing the association of preoperative HIIT vs standard hospital care with preoperative CRF and postoperative outcomes. Data Sources: Data sources included Medline, Embase, Cochrane Central Register of Controlled Trials Library, and Scopus databases with no language constraints, including abstracts and articles published before May 2023. Study Selection: The databases were searched for randomized clinical trials and prospective cohort studies with HIIT protocols in adult patients undergoing major surgery. Thirty-four of 589 screened studies met initial selection criteria. Data Extraction and Synthesis: A meta-analysis was performed according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Data were extracted by multiple independent observers and pooled in a random-effects model. Main Outcomes and Measures: The primary outcome was change in CRF, as measured by either peak oxygen consumption (V̇o2 peak) or 6-Minute Walk Test (6MWT) distance. Secondary outcomes included postoperative complications; hospital length of stay (LOS); and changes in quality of life, anaerobic threshold, and peak power output. Results: Twelve eligible studies including 832 patients were identified. Pooled results indicated several positive associations for HIIT when compared with standard care either on CRF (V̇o2 peak, 6MWT, anaerobic threshold, or peak power output) or postoperative outcomes (complications, LOS, quality of life), although there was significant heterogeneity in study results. In 8 studies including 627 patients, there was moderate-quality evidence of significant improvement in V̇o2 peak (cumulative mean difference, 2.59 mL/kg/min; 95% CI, 1.52-3.65 mL/kg/min; P < .001). In 8 studies including 770 patients, there was moderate-quality evidence of a significant reduction in complications (odds ratio, 0.44; 95% CI, 0.32-0.60; P < .001). There was no evidence that HIIT differed from standard care in hospital LOS (cumulative mean difference, -3.06 days; 95% CI, -6.41 to 0.29 days; P = .07). The analysis showed a high degree of heterogeneity in study outcomes and an overall low risk of bias. Conclusions and Relevance: The results of this meta-analysis suggest that preoperative HIIT may be beneficial for surgical populations through the improvement of exercise capacity and reduced postoperative complications. These findings support including HIIT in prehabilitation programs before major surgery. The high degree of heterogeneity in both exercise protocols and study results supports the need for further prospective, well-designed studies.

Short-term high-intensity interval training improves fitness before surgery: A randomized clinical trial.

PURPOSE: Improving cardiopulmonary reserve, or peak oxygen consumption( V ˙ O2peak ), may reduce postoperative complications; however, this may be difficult to achieve between diagnosis and surgery. Our primary aim was to assess the efficacy of an approximate 14-session, preoperative high-intensity interval training(HIIT) program to increase V ˙ O2peak by a clinically relevant 2 ml·kg-1 ·min-1 . Our secondary aim was to document clinical outcomes. METHODOLOGY: In this prospective study, participants aged 45-85 undergoing major abdominal surgery were randomized to standard care or 14 sessions of HIIT over 4 weeks. HIIT sessions involved approximately 30 min of stationary cycling. Interval training alternated 1 min of high (with the goal of reaching 90% max heart rate at least once during the session) and low/moderate-intensity cycling. Cardiopulmonary exercise testing(CPET) measured the change in V ˙ O2peak from baseline to surgery. Clinical outcomes included postoperative complications, length of stay(LOS), and Short Form 36 quality of life questionnaire(SF-36). RESULTS: Of 63 participants, 46 completed both CPETs and 50 completed clinical follow-up. There was a significant improvement in the HIIT group's mean ± SD V ˙ O2peak (HIIT 2.87 ± 1.94 ml·kg1 ·min-1 vs standard care 0.15 ± 1.93, with an overall difference of 2.73 ml·kg1 ·min-1 95%CI [1.53, 3.93] p < 0.001). There were no statistically significant differences between groups for clinical outcomes, although the observed differences consistently favored the exercise group. This was most notable for total number of complications (0.64 v 1.16 per patient, p = 0.07), SF-36 physical component score (p = 0.06), and LOS (mean 5.5 v 7.4 days, p = 0.07). CONCLUSIONS: There was a significant improvement in V ˙ O2peak with a four-week preoperative HIIT program. Further appropriately powered work is required to explore the impact of preoperative HIIT on postoperative clinical outcomes.

Additional cardiovascular fitness when progressing from moderate- to high-intensity exercise training in previously trained breast cancer survivors.

PURPOSE: Cardiovascular disease, often secondary to chemotherapy, is the leading cause of death in BC survivors. Increased aerobic capacity improves post-rehabilitation survival; however, many cancer rehabilitation programs are limited to lower intensity training. High-intensity interval training (HIIT) is associated with the largest improvements in aerobic capacity; therefore, this study aimed to determine whether HIIT would cause a greater increase in VO2peak than continuous moderate-intensity (MICT) exercise in previously trained BC survivors. METHODS: Twenty BC survivors who had completed a low/moderate-intensity exercise rehabilitation program performed a VO2peak test and received a dual-energy X-ray absorptiometry (DXA) scan at baseline and after randomization into a 12-week HIIT or MICT program. ANOVA with repeated measures determined the effects of the different training programs on aerobic capacity and body composition. RESULTS: Both groups began the training program near or above age- and sex-matched VO2peak norms. Pre- to post-intervention improvements in VO2peak (P = 0.006) and waist circumference (P = 0.007) were found in both groups; however, there were no between-group differences. Minute ventilation and peak workload increased in the HIIT group (P < 0.05) but not the MICT group. Body composition was not different after either training program. CONCLUSIONS: These data suggest that transitioning from low/moderate-intensity exercise to moderate/high-intensity exercise causes further clinically relevant increases in VO2peak in previously trained BC survivors. HIIT did not cause a significantly greater improvement in VO2peak than MICT; however, future studies with greater intensity and frequency of training are encouraged.

Protocol, and practical challenges, for a randomised controlled trial comparing the impact of high intensity interval training against standard care before major abdominal surgery: study protocol for a randomised controlled trial.

BACKGROUND: Risk factors, such as the number of pre-existing co-morbidities, the extent of the underlying pathology and the magnitude of the required operation, cannot be changed before surgery. It may, however, be possible to improve the cardiopulmonary fitness of the patient with an individualised exercise program. We are performing a randomised controlled trial (RCT) assessing the impact of High Intensity Interval Training (HIIT) on preoperative cardiopulmonary fitness and postoperative outcomes in patients undergoing major abdominal surgery. METHODS: Consecutive eligible patients undergoing elective abdominal surgery are being randomised to HIIT or standard care in a 1:1 ratio. Participants allocated to HIIT will perform 14 exercise sessions on a stationary cycle ergometer, over a period of 4-6 weeks before surgery. The sessions, which are individualised, aim to start with ten repeated 1-min blocks of intense exercise with a target of reaching a heart rate exceeding 90% of the age predicted maximum, followed by 1 min of lower intensity cycling. As endurance improves, the duration of exercise is increased to achieve five 2-min intervals of high intensity exercise followed by 2 min of lower intensity cycling. Each training session lasts approximately 30 min. The primary endpoint, change in peak oxygen consumption (Peak VO2) measured during cardiopulmonary exercise testing, is assessed at baseline and before surgery. Secondary endpoints include postoperative complications, length of hospital stay and three clinically validated scores: the surgical recovery scale; the postoperative morbidity survey; and the SF-36 quality of life score. The standard deviation for changes in Peak VO2 will be assessed after the first 30 patients and will be used to calculate the required sample size. DISCUSSION: We want to assess if 14 sessions of HIIT is sufficient to improve Peak VO2 by 2 mL/kg/min in patients undergoing major abdominal surgery and to explore the best clinical endpoint for a subsequent RCT designed to assess if improving Peak VO2 will translate into improving clinical outcomes after surgery. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry, ACTRN12617000587303 . Registered on 26 April 2017.

A randomized controlled graded exercise trial for chronic fatigue syndrome: outcomes and mechanisms of change.

The aim of this study was to investigate the potential mechanisms underlying the efficacy of graded exercise therapy for chronic fatigue syndrome (CFS). Forty-nine CFS patients were randomized to a 12-week graded exercise programme or to standard medical care. At the end of treatment the exercise group rated themselves as significantly more improved and less fatigued than the control group. A decrease in symptom focusing rather than an increase in fitness mediated the treatment effect. Graded exercise appears to be an effective treatment for CFS and it operates in part by reducing the degree to which patients focus on their symptoms.