Upper-Limb High-Intensity Interval Training or Passive Heat Therapy to Optimize Cardiorespiratory Fitness Prior to Total Hip or Knee Arthroplasty: A Randomized Controlled Trial.

OBJECTIVE: Preoperative exercise training, or prehabilitation, aims to optimize cardiorespiratory fitness before surgery to reduce the risk of adverse perioperative events and delayed recovery. However, traditional exercise such as walking and cycling can be difficult for people with degenerative joint diseases of the lower limbs, such as osteoarthritis. The purpose of this study was to compare the effect of three low-impact interventions on cardiorespiratory fitness, physical function, and subjective health before total hip or knee arthroplasty. METHODS: This was a randomized controlled trial involving 93 participants with severe knee or hip osteoarthritis awaiting joint replacement surgery. Participants underwent cardiopulmonary exercise testing (to measure peak oxygen consumption [ V ̇ $$ \dot{V} $$ O2 ]), then were randomized to heat therapy (Heat; 20-30 min immersed in 40°C water followed by ~15 min light-resistance exercise), high-intensity interval training (HIIT; 6-8 × 60 s intervals on a cross-trainer or arm ergometer at ~90%-100% peak V ̇ $$ \dot{V} $$ O2 ), or home-based exercise (Home; ~15 min light-resistance exercise); for up to 36 sessions (3 sessions per week for 12 weeks). RESULTS: Peak V ̇ $$ \dot{V} $$ O2 increased by 16% across HIIT and to a greater extent than Heat (+2.5 mL × min-1 × kg-1 [95% CI: 0.5-4.4], P = 0.009) and Home (+3.2 mL × min-1 × kg-1 [1.2-5.2], P = 0.001). The anaerobic threshold increased across HIIT (+1.5 mL × min-1 × kg-1 [0.7-2.3], P < 0.001) and Heat (+1.2 mL × min-1 × kg-1 [0.4-1.9], P = 0.004), but not Home (-0.5 mL × min-1 × kg-1 [-1.3 to 0.3], P = 0.248). Subjective severity of osteoarthritis was unchanged with any intervention (P ≥ 0.250). CONCLUSION: Heat therapy and HIIT improved indices of cardiorespiratory fitness preoperatively in patients who have difficulty performing lower-limb exercise.

Acute and adaptive cardiovascular and metabolic effects of passive heat therapy or high-intensity interval training in patients with severe lower-limb osteoarthritis.

Exercise is painful and difficult to perform for patients with severe lower-limb osteoarthritis; consequently, reduced physical activity contributes to increased cardiometabolic disease risk. The aim of this study was to characterize the acute and adaptive cardiovascular and metabolic effects of two low or no impact therapies in patients with severe lower-limb osteoarthritis: passive heat therapy (Heat) and high-intensity interval training (HIIT) utilizing primarily the unaffected limbs, compared to a control intervention of home-based exercise (Home). Participants completed up to 12 weeks of either Heat (20-30 min immersed in 40°C water followed by ~15-min light resistance exercise), HIIT (6-8 × 60-s intervals on a cross-trainer or arm ergometer at ~90-100% peak V ̇ $$ \dot{V} $$ O2 ) or Home (~15-min light resistance exercise); all 3 sessions/week. Reductions in systolic (12 & 10 mm Hg), diastolic (7 & 4 mm Hg), and mean arterial (8 & 6 mm Hg) blood pressure (BP) were observed following one bout of Heat or HIIT exposure, lasting for the duration of the 20-min monitoring period. Across the interventions (i.e., 12 weeks), resting systolic BP and diastolic BP decreased with Heat (-9 & -4 mm Hg; p < 0.001) and HIIT (-7 & -3 mm Hg; p ≤ 0.011), but not Home (0 & 0 mm Hg; p ≥ 0.785). The systolic and diastolic BP responses to an acute exposure of Heat or HIIT in the first intervention session were moderately correlated with adaptive responses across the intervention (r ≥ 0.54, p ≤ 0.005). Neither intervention improved indices of glycemic control (p = 0.310). In summary, both Heat and HIIT induced potent immediate and adaptive hypotensive effects, and the acute response was moderately predictive of the long-term response.

Physiological relationship between cardiorespiratory fitness and fitness for surgery: a narrative review.

Epidemiological evidence has highlighted a strong relationship between cardiorespiratory fitness and surgical outcomes; specifically, fitter patients possess heightened resilience to withstand the surgical stress response. This narrative review draws on exercise and surgical physiology research to discuss and hypothesise the potential mechanisms by which higher fitness affords perioperative benefit. A higher fitness, as indicated by higher peak rate of oxygen consumption and ability to sustain metabolic homeostasis (i.e. higher anaerobic threshold) is beneficial postoperatively when metabolic demands are increased. However, the associated adaptations with higher fitness, and the related participation in regular exercise or physical activity, might also underpin the observed perioperative benefit through a process of hormesis, a protective adaptive response to the moderate and intermittent stress of exercise. Potential mediators discussed include greater antioxidant capacity, metabolic flexibility, glycaemic control, lean body mass, and improved mood.

Nature and delivery of cardiac rehabilitation in New Zealand: are services equitable to other high-income countries?

AIMS: To compare the nature and delivery of cardiac rehabilitation (CR) services within New Zealand by island (North vs South; NI, SI), and to other high-income countries (HICs). METHODS: In this cross-sectional study, secondary analysis of an online survey of CR programmes globally was undertaken. Results from New Zealand were compared to data from other HICs with CR. RESULTS: Twenty-seven (62.7%) out of 43 CR programmes in New Zealand (n=18/31, 66.7% respondents from NI) and 619 (43.1%) from 28 other HICs completed the survey. New Zealand CR programmes offered a median of 16.0 sessions/patient (interquartile range (IQR)=12.0-36.0; vs 21.6 sessions in other HICs, IQR=12.0-36.0, p=0.016), delivered by a team of 6.0 staff (IQR=5.5-7.0; vs 7.0 staff; IQR=5.0-9.0, p=0.012). New Zealand programmes were significantly less comprehensive than other HICs (p=0.002); within New Zealand, NI programmes were more likely to provide an initial and end-of-programme assessment, supervised exercise training and depression screening, compared to SI programmes (all p<0.05). New Zealand more often offered CR in an alternative setting (n=14, 58.3%), compared to other HICs (n=190, 36.5%), p=0.03). CONCLUSIONS: CR programmes in New Zealand offer fewer sessions and have fewer elements compared to other HICs, and disparity exists in programmes across New Zealand. More investment is needed to ensure CR in New Zealand meets international guidelines.

Is moderate intensity exercise training combined with high intensity interval training more effective at improving cardiorespiratory fitness than moderate intensity exercise training alone?

The purpose of this study was to compare the effectiveness of either continuous moderate intensity exercise training (CMIET) alone vs. CMIET combined with a single weekly bout of high intensity interval training (HIIT) on cardiorespiratory fitness. Twenty nine sedentary participants (36.3 ± 6.9 yrs) at moderate risk of cardiovascular disease were recruited for 12 weeks of exercise training on a treadmill and cycle ergometer. Participants were randomised into three groups: CMIET + HIIT (n = 7; 8-12 x 60 sec at 100% VO2max, 150 sec active recovery), CMIET (n = 6; 30 min at 45-60% oxygen consumption reserve (VO2R)) and a sedentary control group (n = 7). Participants in the CMIET + HIIT group performed a single weekly bout of HIIT and four weekly sessions of CMIET, whilst the CMIET group performed five weekly CMIET sessions. Probabilistic magnitude-based inferences were determined to assess the likelihood that the true value of the effect represents substantial change. Relative VO2max increased by 10.1% (benefit possible relative to control) in in the CMIET + HIIT group (32.7 ± 9.2 to 36.0 ± 11.5 mL·kg(-1)·min(-1)) and 3.9% (benefit possible relative to control) in the CMIET group (33.2 ± 4.0 to 34.5 ± 6.1 mL·kg(-1)·min(-1)), whilst there was a 5.7% decrease in the control group (30.0 ± 4.6 to 28.3 ± 6.5 mL·kg(-1)·min(-1)). It was 'unclear' if a clinically significant difference existed between the effect of CMIET + HIIT and CMIET on the change in VO2max. Both exercising groups showed clinically meaningful improvements in VO2max. Nevertheless, it remains 'unclear' whether one type of exercise training regimen elicits a superior improvement in cardiorespiratory fitness relative to its counterpart. Key PointsBoth continuous moderate intensity exercise training (CMIET) alone and CMIET combined with a single weekly bout of high intensity interval training (CMIET + HIIT) elicit 'possibly beneficial' clinically meaningful improvements in cardiorespiratory fitness.Cardiorespiratory fitness improved by ~1.0 MET in the CMIET + HIIT exercise intervention group, which likely leads to important long-term prevention implications as a 1 MET increase in cardiorespiratory fitness has been linked with an 18% reduction in deaths due to CVD.There was 100% adherence to interval sessions in the CMIET + HIIT group, suggesting this combination of training can be well-tolerated in previously inactive overweight/obese individuals.