Short-term effects of a 3-week interval training program on heart rate variability in chronic heart failure. A randomised controlled trial.

BACKGROUND: Exaggerated sympathetic nervous system activity associated with low heart rate variability (HRV) is considered to trigger cardiac arrhythmias and sudden death. Regular exercise training is efficient to improve autonomic balance. OBJECTIVE: We aimed to verify the superiority of high-intensity interval training (HIIT) to enhance HRV, cardiorespiratory fitness and cardiac function as compared with moderate intensity continuous training (MICT) in a short, intense cardiac rehabilitation program. METHODS: This was a prospective, monocentric, evaluator-blinded, randomised (1:1) study with a parallel two-group design. Overall, 31 individuals with voluntary chronic heart failure (CHF) (left ventricular ejection fraction [LVEF]<45%) were allocated to MICT (n=15) or HIIT (n=16) for a short rehabilitation program (mean [SD] 27 [4] days). Participants underwent 24-hr electrocardiography, echocardiography and a cardiopulmonary exercise test at entry and at the end of the study. RESULTS: High-frequency power in normalized units (HFnu%) measured as HRV increased with HIIT (from 21.2% to 26.4%, P<0.001) but remained unchanged with MICT (from 23.1% to 21.9%, P=0.444, with a significant intergroup difference, P=0.003). Resting heart rate (24-hr Holter electrocardiography) decreased significantly for both groups (from 68.2 to 64.6 bpm and 66.0 to 63.5 bpm for MICT and HIIT, respectively, with no intergroup difference, P=0.578). The 2 groups did not differ in premature ventricular contractions. Improvement in peak oxygen uptake was greater with HIIT than MICT (+21% vs. +5%, P=0.009). LVEF improved with only HIIT (from 36.2% to 39.5%, P=0.034). CONCLUSIONS: In this short rehabilitation program, HIIT was significantly superior to the classical MICT program for enhancing parasympathetic tone and peak oxygen uptake. CLINICALTRIALS. GOV IDENTIFIER: NCT03603743.

Whole-body strength training with Huber Motion Lab and traditional strength training in cardiac rehabilitation: A randomized controlled study.

BACKGROUND: Isometric strengthening has been rarely studied in patients with coronary heart disease (CHD), mainly because of possible potential side effects and lack of appropriate and reliable devices. OBJECTIVE: We aimed to compare 2 different modes of resistance training, an isometric mode with the Huber Motion Lab (HML) and traditional strength training (TST), in CHD patients undergoing a cardiac rehabilitation program. DESIGN: We randomly assigned 50 patients to HML or TST. Patients underwent complete blinded evaluation before and after the rehabilitation program, including testing for cardiopulmonary exercise, maximal isometric voluntary contraction, endothelial function and body composition. RESULTS: After 4 weeks of training (16 sessions), the groups did not differ in body composition, anthropometric characteristics, or endothelial function. With HML, peak power output (P=0.035), maximal heart rate (P<0.01) and gain of force measured in the chest press position (P<0.02) were greater after versus before training. CONCLUSION: Both protocols appeared to be well tolerated, safe and feasible for these CHD patients. A training protocol involving 6s phases of isometric contractions with 10s of passive recovery on an HML device could be safely implemented in rehabilitation programs for patients with CHD and improve functional outcomes.

Improved Walking Claudication Distance with Transcutaneous Electrical Nerve Stimulation: An Old Treatment with a New Indication in Patients with Peripheral Artery Disease.

OBJECTIVE: The aim of this study was to determine whether 45 mins of transcutaneous electrical nerve stimulation before exercise could delay pain onset and increase walking distance in peripheral artery disease patients. DESIGN: After a baseline assessment of the walking velocity that led to pain after 300 m, 15 peripheral artery disease patients underwent four exercise sessions in a random order. The patients had a 45-min transcutaneous electrical nerve stimulation session with different experimental conditions: 80 Hz, 10 Hz, sham (presence of electrodes without stimulation), or control with no electrodes, immediately followed by five walking bouts on a treadmill until pain occurred. The patients were allowed to rest for 10 mins between each bout and had no feedback concerning the walking distance achieved. RESULTS: Total walking distance was significantly different between T10, T80, sham, and control (P < 0.0003). No difference was observed between T10 and T80, but T10 was different from sham and control. Sham, T10, and T80 were all different from control (P < 0.001). There was no difference between each condition for heart rate and blood pressure. CONCLUSIONS: Transcutaneous electrical nerve stimulation immediately before walking can delay pain onset and increase walking distance in patients with class II peripheral artery disease, with transcutaneous electrical nerve stimulation of 10 Hz being the most effective.

Whole-body strength training using a Huber Motion Lab in coronary heart disease patients: safety, tolerance, fuel selection, and energy expenditure aspects and optimization.

OBJECTIVE: The aim of this study was to investigate safety, tolerance, relative exercise intensity, and muscle substrate oxidation during sessions performed on a Huber Motion Lab in coronary heart disease patients. DESIGN: After an assessment of Vo2 peak, 20 coronary heart disease patients participated in two different exercises performed in random order at 40% and 70% (W40 and W70) of the maximal isometric voluntary contraction. RESULTS: No significant arrhythmia or abnormal blood pressure responses occurred during either session, and no muscle soreness was reported within 48 hrs posttest. The authors found a difference between W40 and W70 sessions for mean (standard deviation) ventilation (25.1% [8%] and 32.1% [9%] of maximal ventilation, respectively; P = 0.04) and a small difference for mean (standard deviation) heart rate (73 [7] and 79 [8] beats/min, respectively; P < 0.01). When compared with the W40, the W70 was associated with higher active energy expenditure (2.4 [0.6] and 3.1 [0.9] Kcal/min, respectively; P < 0.0001) and a similar mean (standard deviation) oxygen uptake (5.5 [1] and 6.6 [1] ml/min per kilogram, respectively; P = 0.07). The qualitative percentages of carbohydrates and lipids oxidized were 71% and 29%, respectively, at W40 and 91% and 9%, respectively, at W70. CONCLUSIONS: Both protocols, which consisted of repeating 6-sec phases of contractions with 10 secs of passive recovery on the Huber Motion Lab, seemed to be well tolerated, safe, and feasible in this group of coronary heart disease patients.

Telephone support oriented by accelerometric measurements enhances adherence to physical activity recommendations in noncompliant patients after a cardiac rehabilitation program.

OBJECTIVE: To assess the efficacy of a strategy, based on telephone support oriented by accelerometer measurements, on the adherence to physical activity (PA) recommendations in cardiac patients not achieving PA recommendations. DESIGN: Prospective and randomized study. SETTING: A cardiac rehabilitation program (CRP) at a clinic. PARTICIPANTS: Stable, noncompliant cardiac (coronary artery disease, heart failure, post-cardiovascular surgery) patients (weekly moderate-intensity PA <150 min) were randomly assigned to an intervention group (n=19) or a control group (n=10). INTERVENTIONS: The intervention group wore an accelerometer for 8 weeks. Every 15 days, feedback and support were provided by telephone. The control group wore the accelerometer during the 8th week of the intervention only. MAIN OUTCOME MEASURES: Active energy expenditure (EE) (in kilocalories) and the time spent doing light, moderate, or intense PA (minutes per week). RESULTS: In the intervention group, the time spent at moderate-intensity PA increased from 95.6±80.7 to 137.2±87.5 min/wk between the 1st and 8th week (P=.002), with 36.8% of the sample achieving the target amount of moderate-intensity PA. During the 8th week, the EE averaged 543.7±144.1 kcal and 266.7±107.4 kcal in the intervention group and control group, respectively (P=.004). CONCLUSIONS: Telephone support based on accelerometer recordings appeared to be an effective strategy to improve adherence to PA in noncompliant patients. This intervention could be implemented after a CRP as an inexpensive, modern, and easy-to-use strategy.