Aerobic exercise intensity assessment and prescription in cardiac rehabilitation: a joint position statement of the European Association for Cardiovascular Prevention and Rehabilitation, the American Association of Cardiovascular and Pulmonary Rehabilitation, and the Canadian Association of Cardiac Rehabilitation

Interrater and intrarater reliability of ventilatory thresholds determined in individuals with spinal cord injury

STUDY DESIGN

Cross-sectional.

OBJECTIVES

Individualized training regimes are often based on ventilatory thresholds (VTs). The objectives were to study: (1) whether VTs during arm ergometry could be determined in individuals with spinal cord injury (SCI), (2) the intrarater and interrater reliability of VT determination.

SETTING

University research laboratory.

METHODS

Thirty graded arm crank ergometry exercise tests with 1-min increments of recreationally active individuals (tetraplegia (N = 11), paraplegia (N = 19)) were assessed. Two sports physicians assessed all tests blinded, randomly, in two sessions, for VT1 and VT2, resulting in 240 possible VTs. Power output (PO), heart rate (HR), and oxygen uptake (VO₂) at each VT were compared between sessions or raters using paired samples t-tests, Wilcoxon signed-rank tests, intraclass correlation coefficients (ICC, relative agreement), and Bland-Altman plots (random error, absolute agreement).

RESULTS

Of the 240 VTs, 217 (90%) could be determined. Of the 23 undetermined VTs, 2 (9%) were VT1 and 21 (91%) were VT2; 7 (30%) among individuals with paraplegia, and 16 (70%) among individuals with tetraplegia. For the successfully determined VTs, there were no systematic differences between sessions or raters. Intrarater and interrater ICCs for PO, HR, and VO₂ at each VT were high to very high (0.82-1.00). Random error was small to large within raters, and large between raters.

CONCLUSIONS

For VTs that could be determined, relative agreement was high to very high, absolute agreement varied. For some individuals, often with tetraplegia, VT determination was not possible, thus other methods should be considered to prescribe exercise intensity.

[Non-randomized trial to evaluate a continuous physiotherapy program versus interval in overweight patients suffering from acute coronary syndrome]

Presentamos un ensayo no aleatorizado de un programa de fisioterapia continuo frente a interválico para pacientes con sobrepeso y síndrome coronario agudo.

Objetivo

Detectar diferencias entre un programa de fisioterapia (PF) continuo (CONT) y uno interválico (INT) en pacientes con sobrepeso y síndrome coronario agudo, respecto a parámetros antropométricos, analíticos, frecuencia cardiaca de reposo, adherencia a la intervención, desgaste, seguridad y tolerancia.

Diseño

Estudio multicéntrico cuasiexperimental con diseño pre-post, no aleatorizado con muestreo por conveniencia con 2 brazos de tratamiento.

Emplazamiento

Centros de prevención cardiaca comunitaria (Departamentos de Salud Manises, Valencia-La Fe, Játiva-Onteniente).

Participantes

Se consideró a 339 sujetos con sobrepeso y síndrome coronario agudo que vivían en la comunidad; mayores de 18 años; sin contraindicación para realizar ejercicio físico; sin participación previa en PF.

Intervenciones

Se realizó un PF con entrenamiento CONT o uno con entrenamiento INT (2 meses). Cada sesión se dividió en calentamiento, esfuerzo y enfriamiento. El esfuerzo se realizó a intensidad 12-13 Borg y con frecuencia cardiaca calculada según la máxima obtenida en ergometría basal.

Mediciones principales

Se analizó el índice de masa corporal, perímetro abdominal, perfil lipídico, glucemia, hemoglobina glicosilada, frecuencia cardiaca de reposo, adherencia, desgaste, seguridad y tolerancia.

Resultados

El grupo CONT mostró diferencias significativamente mejores en las variables índice de masa corporal, perímetro abdominal, colesterol total, colesterol LDL, triglicéridos, HbA1C, glucemia y frecuencia cardiaca de reposo, respecto al PF INT. No hubo diferencias entre grupos respecto a adherencia, desgaste, seguridad y tolerancia.

Conclusiones

El grupo CONT produjo mejores resultados en todas las variables excepto en el colesterol HDL. Ambos programas registraron una elevada adherencia, seguridad y tolerancia.

Exercise intensity affects acute neurotrophic and neurophysiological responses poststroke

Aerobic exercise may acutely prime the brain to be more responsive to rehabilitation, thus facilitating neurologic recovery from conditions like stroke. This aerobic priming effect could occur through multiple mechanisms, including upregulation of circulating brain-derived neurotrophic factor (BDNF), increased corticospinal excitability, and decreased intracortical inhibition. However, optimal exercise parameters for targeting these mechanisms are poorly understood. This study tested the effects of exercise intensity on acute BDNF and neurophysiological responses. Sixteen ambulatory persons >6 mo poststroke performed three different 20-min exercise protocols in random order, approximately 1 wk apart, including the following: 1) treadmill high-intensity interval training (HIT-treadmill); 2) seated-stepper HIT (HIT-stepper); and 3) treadmill moderate-intensity continuous exercise (MCT-treadmill). Serum BDNF and transcranial magnetic stimulation measures of paretic lower limb excitability and inhibition were assessed at multiple time points during each session. Compared with MCT-treadmill, HIT-treadmill elicited significantly greater acute increases in circulating BDNF and corticospinal excitability. HIT-stepper initially showed BDNF responses similar to HIT-treadmill but was no longer significantly different from MCT-treadmill after decreasing the intensity in reaction to two hypotensive events. Additional regression analyses showed that an intensity sufficient to accumulate blood lactate appeared to be important for eliciting BDNF responses, that the interval training approach may have facilitated the corticospinal excitability increases, and that the circulating BDNF response was (negatively) related to intracortical inhibition. These findings further elucidate neurologic mechanisms of aerobic exercise and inform selection of optimal exercise-dosing parameters for enhancing acute neurologic effects. NEW & NOTEWORTHY Acute exercise-related increases in circulating BDNF and corticospinal excitability are thought to prime the brain for learning. Our data suggest that these responses can be obtained among persons with stroke using short-interval treadmill high-intensity interval training, that a vigorous aerobic intensity sufficient to generate lactate accumulation is needed to increase BDNF, that interval training facilitates increases in paretic quadriceps corticospinal excitability, and that greater BDNF response is associated with lesser intracortical inhibition response.

Is cardiorespiratory fitness independently associated with the biochemical profile in overweight/obese adults with primary hypertension? The EXERDIET-HTA study

Cardiorespiratory fitness (CRF) is positively associated with enhanced cardiovascular health. This cross-sectional study aimed to determine associations between CRF and the biochemical profile of overweight/obese adults diagnosed with primary hypertension (HTN). Does cardiorespiratory fitness (exposure) positively affect the biochemical profile (outcome) in overweight/obese individuals suffering from HTN? Assessment with anthropometric, ambulatory blood pressure monitoring (24 h), CRF (peak oxygen uptake, V̇O_2peak) and biochemical analysis was performed on 214 participants (138 men, 76 women). A series of linear and logistic regression analyses were conducted. Participants were divided into CRF tertiles (classified as low, moderate and high CRF). The CRF was independently and inversely associated with aspartate aminotransferase (AST; β = -0.328, p < .05) and alanine aminotransferase (ALT; β = -0.376, p < .01) concentrations. C-reactive protein, AST/ALT ratio, gamma-glutamyl transpeptidase, total cholesterol/high-density lipoprotein cholesterol ratio, glucose, insulin and insulin resistance index (HOMA-IR), were all associated, but not independently, with CRF in linear and/or unadjusted logistic regression models. However, independently, logistic regression revealed that glucose was associated with the moderate CRF group. Findings suggest that a lower CRF is associated with an unhealthy biochemical profile in non-physically active and overweight/obese individuals with HTN. As such, this population should look to increase physical activity in order to improve their CRF and biochemical profile.

Aerobic Training Efficacy in Inflammation, Neurotrophins, and Function in Chronic Stroke Persons: A Randomized Controlled Trial Protocol

BACKGROUND

Neuroinflammation is an important part of stroke pathophysiology and has both detrimental and beneficial effects after stroke. Besides that the enhancement of neurotrophins seems to be related to improvements in stroke recovery. Evidences suggest that exercise plays a role in modulating anti-inflammatory and neurotrophic effects. However, little is known about its impact in stroke survivors, mainly in chronic stroke. The purpose of this study is to investigate the efficacy of moderate-intensity treadmill exercise in changing inflammatory mediators, interleukin-6 (IL-6), soluble tumor necrosis factor receptors I and II (sTNFRI, sTNFRII), interleukin-10 (IL-10), and brain-derived neurotrophic factor (BDNF) levels in chronic stroke patients. The secondary objective is to investigate the effects of training in improve mobility and exercise capacity.

METHODS

This is a randomized controlled trial. Chronic stroke patients will be randomized to an experimental or control group, and will receive group interventions three times per week, over 12 weeks. The experimental group will receive moderate-intensity (60%-80% of maximum heart rate reserve) treadmill exercise. Control group will perform walking training on the ground (<40% of maximum heart rate reserve). Primary outcomes include IL-6, sTNFRI, sTNFRII, IL-10, and BDNF levels. Secondary outcomes include mobility and exercise capacity. Outcomes will be measured at baseline, postintervention, and at the 4-week follow-up.

DISCUSSION

The findings of this trial have the potential to provide important insights regarding the effects of an aerobic physical program in the inflammatory process and in the neuronal plasticity in stroke persons and its impact on mobility and exercise capacity.

Vasodilation and Reduction of Systolic Blood Pressure after One Session of High-Intensity Interval Training in Patients With Heart Failure with Preserved Ejection Fraction

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF) is a multifactorial syndrome characterized by a limited exercising capacity. High-intensity interval training (HIIT) is an emerging strategy for exercise rehabilitation in different settings. In patients with HFpEF, HIIT subacute effects on endothelial function and blood pressure are still unknown.

OBJECTIVE

To evaluate the subacute effect of one HIIT session on endothelial function and blood pressure in patients with HFpEF.

METHODS

Sixteen patients with HFpEF underwent a 36-minute session of HIIT on a treadmill, alternating four minutes of high-intensity intervals with three minutes of active recovery. Brachial artery diameter, flow-mediated dilation, and blood pressure were assessed immediately before and 30 minutes after the HIIT session. In all analyses, p <0.05 was considered statistically significant.

RESULTS

There was an increase in brachial artery diameter (pre-exercise: 3.96 ± 0.57 mm; post-exercise: 4.33 ± 0.69 mm; p < 0.01) and a decrease in systolic blood pressure (pre-exercise: 138 ± 21 mmHg; post-exercise: 125 ± 20 mmHg; p < 0.01). Flow-mediated dilation (pre-exercise: 5.91 ± 5.20%; post-exercise: 3.55 ± 6.59%; p = 0.162) and diastolic blood pressure (pre-exercise: 81 ± 11 mmHg; post-exercise: 77 ± 8 mmHg; p = 1.000) did not change significantly. There were no adverse events throughout the experiment.

CONCLUSIONS

One single HIIT session promoted an increase in brachial artery diameter and reduction in systolic blood pressure, but it did not change flow-mediated dilation and diastolic blood pressure.

Exercise training workloads in cardiac rehabilitation are associated with clinical outcomes in patients with heart failure

BACKGROUND

In patients with coronary heart disease, the exercise workload (i.e., metabolic equivalents of task, METs) at which patients exercise train upon entry and completion of cardiac rehabilitation (CR) are independently related to prognosis. Unknown is the association between exercise training workloads in CR and clinical outcomes in patients with heart failure (HF).

METHODS

Patients with HF who participated in an early outpatient CR program were used in this retrospective analysis. Exercise workloads upon entry and completion of CR were converted to METs. The primary outcome was all-cause mortality and the secondary outcome was HF hospitalization. Cox regression analysis was used to assess the adjusted risk between MET levels in CR and clinical outcomes.

RESULTS

Among 707 patients, the median exercise training workload at the start and end of CR was 2.5 METs (IQR 2.1 to 3.1 METs) and 3.2 METS (IQR 2.7 to 4.1 METs), respectively, for men and 2.2 METs (IQR 1.9 to 2.6 METs) and 2.9 METS (IQR 2.3 to 3.4 METs), respectively, for women. There were 242 deaths and 266 HF hospitalizations. METs achieved at the end of CR had the strongest independent association with all-cause mortality (adjusted HR, 95% CI: 0.58, 0.48-0.70) and HF hospitalization (adjusted HR, 95% CI: 0.62, 0.52-0.74). Each 1 MET higher work load at the end of CR was associated with a 42% and 38% lower adjusted risk for all-cause mortality and HF hospitalization, respectively.

CONCLUSIONS

In a diverse cohort of patients with chronic HF our data suggests that an easily accessible measure of exercise capacity (i.e., METs) that is collected during CR is independently associated with the adjusted risk for both all-cause mortality and HF-specific hospitalization. Training at MET levels <3.5 METs identifies patients that might benefit from closer clinical surveillance and reinforced adherence to medical and lifestyle preventive strategies.

Safety and efficacy of aerobic exercise commenced early after cardiac surgery: A systematic review and meta-analysis

BACKGROUND

Aerobic exercise is a critical component of cardiac rehabilitation following cardiac surgery. Aerobic exercise is traditionally commenced 2-6 weeks following hospital discharge and most commonly includes stationary cycling or treadmill walking. The initiation of aerobic exercise within this early postoperative period not only introduces the benefits associated with aerobic activity sooner, but also ameliorates the negative effects of immobilization associated with the early postoperative period.

METHODS

A systematic review identified all studies reporting safety and efficacy outcomes of aerobic exercise commenced within two weeks of cardiac surgery. A meta-analysis was performed comparing functional, aerobic and safety outcomes in patients receiving early postoperative aerobic exercise compared with usual postoperative care.

RESULTS

Six-minute walk test distance at hospital discharge was 419 ± 88 m in early aerobic exercise patients versus 341 ± 81 m in those receiving usual care (mean difference 69.5 m, 95% confidence interval (CI) 39.2-99.7 m, p < 0.00001). Peak aerobic power was 18.6 ± 3.8 ml·kg^-1·min^-1 in those receiving early exercise versus 15.0 ± 2.1 ml·kg^-1·min^-1 in usual care (mean difference 3.20 ml·kg^-1·min^-1, 95% CI 1.45-4.95, p = 0.0003). There was no significant difference in adverse events rates between the two groups (odds ratio 0.41, 95% CI 0.12-1.42, p = 0.16).

CONCLUSION

Aerobic exercise commenced early after cardiac surgery significantly improves functional and aerobic capacity following cardiac surgery. While adverse event rates did not differ significantly, patients included were very low risk. Further studies are required to adequately assess safety outcomes of aerobic exercise commenced early after cardiac surgery.

A "Blood Relationship" Between the Overlooked Minimum Lactate Equivalent and Maximal Lactate Steady State in Trained Runners. Back to the Old Days?

Maximal Lactate Steady State (MLSS) and Lactate Threshold (LT) are physiologically-related and fundamental concepts within the sports and exercise sciences. Literature supporting their relationship, however, is scarce. Among the recognized LTs, we were particularly interested in the disused “Minimum Lactate Equivalent” (LE_min), first described in the early 1980s. We hypothesized that velocity at LT, conceptually comprehended as in the old days (LE_min), could predict velocity at MLSS (_VMLSS) more accurate than some other blood lactate-related thresholds (BL_RTs) routinely used nowadays by many sport science practitioners. Thirteen male endurance-trained [_VMLSS 15.0 ± 1.1 km·h⁻¹; maximal oxygen uptake (V.O2max) 67.6 ± 4.1 ml·kg⁻¹·min⁻¹] homogeneous (coefficient of variation: ≈7%) runners conducted 1) a submaximal discontinuous incremental running test to determine several BL_RTs followed by a maximal ramp incremental running test for V.O2max determination, and 2) several (4–5) constant velocity running tests to determine _VMLSS with a precision of 0.20 km·h⁻¹. Determined BL_RTs include LE_min and LE_min-related LE_min plus 1 (LE_min+1mM) and 1.5 mmol·L⁻¹ (LE_min+1.5mM), along with well-established BL_RTs such as conventionally-calculated LT, D_max and fixed blood lactate concentration thresholds. LE_min did not differ from LT (P = 0.71; ES: 0.08) and was 27% lower than MLSS (P < 0.001; ES: 3.54). LE_min+1mM was not different from MLSS (P = 0.47; ES: 0.09). LE_min was the best predictor of _VMLSS (r = 0.91; P < 0.001; SEE = 0.47 km·h⁻¹), followed by LE_min+1mM (r = 0.86; P < 0.001; SEE = 0.58 km·h⁻¹) and LE_min+1.5mM (r = 0.84; P < 0.001; SEE = 0.86 km·h⁻¹). There was no statistical difference between MLSS and estimated MLSS using LE_min prediction formula (P = 0.99; ES: 0.001). Mean bias and limits of agreement were 0.00 ± 0.45 km·h⁻¹ and ±0.89 km·h⁻¹. Additionally, LE_min, LE_min+1mM and LE_min+1.5mM were the best predictors of V.O2max (r = 0.72–0.79; P < 0.001). These results support LE_min, an objective submaximal overlooked and underused BL_RT, to be one of the best single MLSS predictors in endurance trained runners. Our study advocates factors controlling LE_min to be shared, at least partly, with those controlling MLSS.

Validity of the modified shuttle walk test to assess cardiorespiratory fitness after exercise intervention in overweight/obese adults with primary hypertension

The study aimed to assess whether the Modified Shuttle Walk Test (MSWT) can detect changes in cardiorespiratory fitness (CRF) in overweight/obese people with hypertension (HTN) after an exercise intervention evaluating the equation presented in the previous research by Jurio-Iriarte et al. Participants (N= 248) performed a peak cardiorespiratory exercise test (CPET) and MSWT before and after 16-weeks of different types of aerobic exercise intervention. The formula of Jurio-Iriarte et al. was used to predict peak oxygen uptake (V̇O_2peak). The correlation between measured and predicted V̇O_2peak was strong (r= 0.76, P< 0.001) with a standard error of estimate (SEE) of 4.9 mL·kg^-1·min^-1; SEE%= 17%. The intraclass correlation coefficient indicates a moderate level of association and agreement (ICC= 0.69; 95% CI 0.34-0.82; P< 0.001) between the measured and predicted V̇O_2peak. When analyzing obese participants alone (N= 128), MSWT equation was more accurate compared to the whole sample (ICC= 0.76; 95% CI 0.52-0.87). The relationship between the change of measured and predicted V̇O_2peak at follow-up was weak (r= 0.42, P< 0.001) with a 31% SEE, and a low level of association and agreement (ICC= 0.31; 95% CI 0.06-0.49; P< 0.001). In conclusion, although MSWT does not accurately predict CRF in people with HTN after exercise intervention and questions its validity, the new equation may have practical application to estimate V̇O_2peak for obese people with HTN when CPET is not available. Abbreviations: AC: Attention Control; BM: Body Mass; BP: Blood Pressure; CI: Confidence Interval; CRF: Cardiorespiratory Fitness; CPET: Cardiopulmonary Exercise Test; HTN: Primary Hypertension; HR: Heart Rate; HV-HIIT: High-Volume and High-Intensity Interval Training; ICC: Intraclass Correlation Coefficient; LV-HIIT: Low-Volume and High-Intensity Interval Training; MICT: Moderate-intensity continuous training; MSWT: Modified Shuttle Walk Test; SD: Standard Deviation; SEE: Standard Error of Estimate; V̇O_2peak: Peak Oxygen Uptake.

Effects of Different Exercise Training Programs on Cardiorespiratory Fitness in Overweight/Obese Adults With Hypertension: A Pilot Study

The goal of the study was to compare the effects of two supervised aerobic exercise programs (moderate-intensity continuous training [MICT] vs. high-intensity interval training [HIIT]) after 8-, 12-, and 16-week intervention periods on cardiorespiratory fitness (CRF) in overweight/obese adults diagnosed with hypertension. Participants ( N = 64) were divided into three intervention cohorts (control group [CG], MICT, and HIIT) and each of these, in turn, into three intervention length cohorts (8, 12, and 16 weeks). Supervised groups exercised twice a week. There were no statistical changes in postintervention periods in CG ( g < 0.1). CRF as assessed by peak oxygen uptake (mL kg^-1·min^-1) increased ( p < .001) in exercise groups (MICT, 3.8 ± 3.3, g = 0.6; HIIT, 4.2 ± 4.7, g = 0.7). The effect of exercise interventions compared with CG was substantial ( p < .02, g > .8) and mostly consequence of HIIT-related effects. The improvements on CRF occurred after 12 and 16 weeks in exercise interventions, rather than in the 8-week group or CG, where Hedges's g index indicated small effect. This study may suggest that both MICT and HIIT exert cardioprotector effects on hypertension in the overweight/obese population. However, short-term training duration (<12 weeks) does not seem to improve CRF, and HIIT intervention might generate higher aerobic capacity, which seems to grow as intervention lengthens.

Isocapnic buffering phase: a useful indicator of exercise endurance in patients with coronary artery disease

OBJECTIVES

The significance of the isocapnic buffering (IB) phase - the period between the first ventilatory threshold (1^st VT) and respiratory compensation point (RCP) - has not been adequately established in patients. This study aimed to determine the clinical significance of the IB phase in patients with coronary artery disease (CAD).

METHODS

This retrospective study included data of sixty-two CAD patients after coronary artery bypass graft (CABG) or percutaneous coronary intervention (PCI) performed in a single medical center between 2010 - 2014. According to their physical conditions, the patients performed incremental cardiopulmonary exercise test (CPET) using a cycle ergometer by the ramp of 5-20 W/min. Correlations between the corrected IB phase duration and age, body mass index (BMI), left ventricular ejection fraction (LVEF), and CPET parameters were evaluated using Pearson correlation coefficients. Variables predicting peak oxygen consumption (VO₂) were evaluated using multiple regression.

RESULTS

Peak VO₂ (p < 0.001), VO₂ at RCP (p < 0.001), ∆O₂/∆WR slope (p < 0.001), maximal partial pressure of end tidal CO₂ (PetCO₂) (p = 0.0012), VE/VCO₂ slope (p = 0.010), BMI (p = 0.012), and age (p = 0.017) were significantly correlated, whereas LVEF (p = 0.246) and VO₂ at 1^st VT (p = 0.179) were not significantly correlated with the corrected IB phase duration. In multiple regression analysis, the corrected IB phase duration, VO₂ at 1^st VT, and ∆O₂/∆WR slope were significantly associated with peak VO₂.

CONCLUSION

The findings indicate that the IB phase duration is a useful indicator of peripheral cardiopulmonary function and endurance performance in CAD patients. These findings could assist the exercise prescription of cardiac rehabilitation for patients with CAD.

Using ramp-incremental V̇O2 responses for constant-intensity exercise selection

Despite compelling evidence to the contrary, the view that oxygen uptake (V̇O₂) increases linearly with exercise intensity (e.g., power output, speed) until reaching its maximum persists within the exercise physiology literature. This viewpoint implies that the V̇O₂ response at any constant intensity is predictable from a ramp-incremental exercise test. However, the V̇O₂ versus task-specific exercise intensity relationship constructed from ramp-incremental versus constant-intensity exercise are not equivalent preventing the use of V̇O₂ responses from 1 domain to predict those of the other. Still, this "linear" translational framework continues to be adopted as the guiding principle for aerobic exercise prescription and there remains in the sport science literature a lack of understanding of how to interpret V̇O₂ responses to ramp-incremental exercise and how to use those data to assign task-specific constant-intensity exercise. The objectives of this paper are to (i) review the factors that disassociate the V̇O₂ versus exercise intensity relationship between ramp-incremental and constant-intensity exercise paradigms; (ii) identify when it is appropriate (or not) to use ramp V̇O₂ responses to accurately assign constant-intensity exercise; and (iii) illustrate the technical and theoretical challenges with prescribing constant-intensity exercise solely on information acquired from ramp-incremental tests. Actual V̇O₂ data collected during cycling exercise and V̇O₂ kinetics modelling are presented to exemplify these concepts. Possible solutions to overcome these challenges are also presented to inform on appropriate intensity selection for individual-specific aerobic exercise prescription in both research and practical settings.

Effects of combined high-intensity aerobic interval training program and Mediterranean diet recommendations after myocardial infarction (INTERFARCT Project): study protocol for a randomized controlled trial

BACKGROUND

Exercise therapy has long been used for rehabilitation purposes after myocardial infarction (MI) and the benefit of regular physical exercise is also well-established. High-intensity interval training (HIIT) has been proposed to be more effective than continuous exercise for improving exercise capacity and health-related adaptations to low-volume (LV) and HIIT are also known. Furthermore, the Mediterranean diet (Mediet) has been widely reported to be a model of healthy eating for its contribution to a favorable health status and a better quality of life, reducing overall mortality. This study will investigate the effects of different HIIT programs (high-volume [HV] vs LV) and Mediet recommendations in clinical condition, cardiorespiratory fitness, biomarkers, ventricular function, and perception of quality of life after MI, and compared to an attention control group that is recommended to Mediet and physical activity without supervision sessions.

METHODS/DESIGN

In this randomized controlled trial, cardiorespiratory fitness, anthropometry, central and peripheral cardiovascular variables, biochemical and nutritional condition, and quality of life will be assessed before and after 16 weeks of intervention in 177 participants diagnosed with MI type 1. All participants will be randomly (1:1:1) assigned to the attention control group or two exercise groups (Mediet recommendations plus supervised aerobic exercise two days/week: (1) HV (40 min) HIIT group and (2) LV (20 min) HIIT group.

DISCUSSION

This study will be the first clinical trial comparing the effects of two different volumes of HIIT programs with Mediet recommendations for people after MI. The results of this study will provide good evidence for physical rehabilitation in this population.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02876952 . Registered on 24 August 2016.

Contemporary Approaches to Prescribing Exercise in Coronary Artery Disease Patients

Health care professionals engaged in the management of coronary artery disease (CAD) patients, both in primary and secondary prevention settings, should possess the knowledge to develop and modify both aerobic exercise as well as musculoskeletal resistance exercise training programs. The traditional exercise prescription (ExRx) for aerobic-type exercise describes the intensity, frequency, duration, and mode of exercise, as well as the rate of progression. The more contemporary ExRx focuses on the energy expenditure associated with all physical activity not just structured exercise bouts. The total "volume or dose" of physical activity is associated with important health outcomes, including the potential to prevent and potentially reverse CAD lesions. Also, emerging evidence supporting the use of high-intensity interval training in CAD patients will also be provided. Furthermore, this review will also address the issue of generating an appropriate ExRx in the absence of maximal exercise "stress" test data, a common occurrence in the primary care setting and in this era of health care cost containment. Prescribing resistance exercise for CAD patients requires careful consideration and will be discussed in this review. Finally, this review will conclude with a section that describes the special considerations and/or modifications for some common comorbidities seen in CAD patients.

Effects of different aerobic exercise programmes with nutritional intervention in sedentary adults with overweight/obesity and hypertension: EXERDIET-HTA study

Background

Both exercise training and diet are recommended to prevent and control hypertension and overweight/obesity.

Purpose

The purpose of this study was to determine the effectiveness of different 16-week aerobic exercise programmes with hypocaloric diet on blood pressure, body composition, cardiorespiratory fitness and pharmacological treatment.

Methods

Overweight/obese, sedentary participants ( n = 175, aged 54.0 ± 8.2 years) with hypertension were randomly assigned into an attention control group (physical activity recommendations) or one of three supervised exercise groups (2 days/week: high-volume with 45 minutes of moderate-intensity continuous training (MICT), high-volume and high-intensity interval training (HIIT), alternating high and moderate intensities, and low-volume HIIT (20 minutes)). All variables were assessed pre- and post-intervention. All participants received the same hypocaloric diet.

Results

Following the intervention, there was a significant reduction in blood pressure and body mass in all groups with no between-group differences for blood pressure. However, body mass was significantly less reduced in the attention control group compared with all exercise groups (attention control –6.6%, high-volume MICT –8.3%, high-volume HIIT –9.7%, low-volume HIIT –6.9%). HIIT groups had significantly higher cardiorespiratory fitness than high-volume MICT, but there were no significant between-HIIT differences (attention control 16.4%, high-volume MICT 23.6%, high-volume HIIT 36.7%, low-volume HIIT 30.5%). Medication was removed in 7.6% and reduced in 37.7% of the participants.

Conclusions

The combination of hypocaloric diet with supervised aerobic exercise 2 days/week offers an optimal non-pharmacological tool in the management of blood pressure, cardiorespiratory fitness and body composition in overweight/obese and sedentary individuals with hypertension. High-volume HIIT seems to be better for reducing body mass compared with low-volume HIIT. The exercise-induced improvement in cardiorespiratory fitness is intensity dependent with low-volume HIIT as a time-efficient method in this population. ClinicalTrials.gov Registration: NCT02283047.

Evolving Role of Exercise Testing in Contemporary Cardiac Rehabilitation

Symptom-limited (maximal) exercise testing before cardiac rehabilitation (CR) was once an unambiguous standard of care. In particular, it served as an important screen for residual ischemia and instability before initiating a progressive exercise training regimen. However, improved revascularization and therapy for coronary heart disease has led many clinicians to downplay this application of exercise testing, especially because such testing is also a potential encumbrance to CR enrollment (delaying ease and efficiency of enrollment after procedures and hospitalizations) and patient burden (eg, added costs, logistic hassle, and anxiety). Nonetheless, exercise testing has enduring value for CR, especially because it reveals dynamic physiological responses as well as ischemia, arrhythmias, and symptoms pertinent to exercise prescription and training and to overall stability and prognosis. Moreover, as indications for CR have expanded, the value of exercise testing and functional assessment is more relevant than ever in the growing population of eligible patients, including those with heart failure, valvular heart disease, and posttransplantation, especially as current patients also tend to be more clinically complex, with advanced ages, multimorbidity, frailty, and obesity. This review focuses on the appropriate use of exercise testing in the CR setting. Graded exercise tests, cardiopulmonary exercise tests, submaximal walking tests, and other functional assessments (strength, frailty) for CR are discussed.

Test–retest reliability and responsiveness to change of clinical tests of physical fitness in patients with acute coronary syndrome included in the SWEDEHEART register

Background:

To maximise the benefits obtainable from exercise-based cardiac rehabilitation, an evaluation of physical fitness using reliable, clinically relevant tests is strongly recommended. Recently, objective tests of physical fitness have been implemented in the SWEDEHEART register. The reliability of these tests has, however, not been examined for patients with acute coronary syndrome.

Aims:

The aim of this study was to assess the test–retest reliability and responsiveness to change of the symptom-limited bicycle ergometer test, the dynamic unilateral heel-lift test and the unilateral shoulder-flexion test in patients with acute coronary syndrome.

Methods:

In a longitudinal study design, a total of 40 patients (mean age 63.8 ± 9.5 years, five women), with ACS, aged < 75 years, were included at a university hospital in Sweden. The intra-class correlation coefficient (ICC) with a 95% confidence interval, standard error of measurement (SEM) and responsiveness in terms of the minimal detectable change were calculated.

Results:

Excellent reliability was found, showing ICC values of 0.98 (0.96–0.99), SEM 4.71 for the bicycle ergometer test, ICC 0.87 (0.75–0.93), SEM 4.62 for the shoulder-flexion test and ICC 0.84 (0.71–0.91), SEM 2.24 for the heel-lift test. The minimal detectable change was 13 W, 13 and 6 repetitions for the bicycle ergometer test, shoulder-flexion and heel-lift tests respectively.

Conclusions:

The test–retest reliability of clinical tests evaluating physical fitness in patients with acute coronary syndrome included in the SWEDEHEART register was excellent. This makes the future comparison and evaluation of treatment effects in large unselected clinical populations of acute coronary syndrome possible.

Evaluation of the Glittre-ADL test as an instrument for classifying functional capacity of individuals with cardiovascular diseases

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Conventional cardiovascular tests exclusively evaluate lower limb function.

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The functional evaluation should include upper limb activities.

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The Glittre-ADL test has the potential to be used in cardiovascular evaluation.

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Glittre-ADL test can discriminate functional classes of individuals with CVD.

Background

The assessment of functional capacity in individuals with cardiovascular disease is closely related to lower limb function. The Glittre-ADL test is a global test to evaluate this patients.

Objective

We aimed to verify whether the Glittre-ADL test discriminates functional status while evaluating individuals with cardiovascular disease.

Methods

A total of 42 participants were evaluated using the Glittre-ADL test Incremental Shuttle Walking Test (shuttle test), Human Activity Profile, and Duke Activity Status Index. Data from the shuttle test, Human Activity Profile, and DASI were divided into tertiles for statistical analysis. The time required to complete the Glittre-ADL test was compared among tertiles of the shuttle test, Duke Activity Status Index and Human Activity Profile using analysis of variance.

Results

There were significant differences between the tertiles of the shuttle test. Tertile 1 was different from tertiles 2 (mean difference, 47.63; 95% CI, 19.86–75.39) and 3 (mean difference, 67.15; 95% CI, 41.25–93.05). For the Duke Activity Status Index there were significant between-group differences. Tertile 1 was different from tertiles 2 (mean difference, 42.45; 95% CI, 8.82–76.09) and 3 (mean difference, 43.56; 95% CI, 13.68–73.44). For the Human Activity Profile there were significant between-group differences. Tertile 3 was different from tertiles 1 (mean difference, 51.46; 95% CI, 21.27–81.64) and 2 (mean difference, 33.01; 95% CI, 3.52–62.51).

Conclusion

The Glittre-ADL test is able to discriminate the functional status in individuals with cardiovascular disease, most of whom have hypertension. The Glittre-ADL test was sensitive to discriminate more functionally affected individuals.

The effect of maximal vs submaximal exertion on postprandial lipid levels in individuals with and without coronary heart disease

BACKGROUND

Decisions about fat consumption and levels of physical activity are among the everyday choices we make in life and risk of coronary heart disease (CHD) can be affected by those choices.

OBJECTIVE

The purpose of this study was to investigate the influence of a standard fat load combined with physical exertion of different intensities on the plasma lipid profile of CHD patients and CHD-free individuals.

METHODS

This study looked at the influence of different intensities of physical exercise on postprandial lipid metabolism in 20 healthy men and 36 men with diagnosis of CHD. Venous blood samples were obtained after overnight fasting, 3 hours after standard fat load (before the physical load), and immediately after maximal or submaximal physical exercise on bicycle ergometer.

RESULTS

After fat load total cholesterol (TC) concentration did not change in either group. However, after the addition of maximal exercise, TC, triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and apolipoprotein (Apo) B increased significantly (P < .01) in both groups. After fat load and maximal exercise, there was no change in high-density lipoprotein cholesterol (HDL-C) in healthy men, but in men with CHD, HDL-C fell significantly (P < .01); and Apo AI rose in healthy men (P < .01) but dropped significantly (P < .01) in men with CHD. Submaximal physical exercise (60% of max VO₂ load for 40 minutes) after fat load decreased TG level in CHD patients (P < .01) and improved other lipid parameters in both groups significantly (↓LDL-C, ↑HDL-C, ↑Apo AI, ↓Apo B, P < .01). We observed a worsening of physical work capacity in men with CHD (significant reduction of duration and total amount of work performed, maximal VO₂, oxygen pulse), during maximal stress test performed 3 hours after fat load. There was a doubling of the number of abnormal stress test results (P < .01). Healthy persons showed an increase in respiratory parameters (ventilation, CO₂ production, maximal VO₂, and oxygen pulse), but no significant change was found in work capacity. Thus, maximal physical exercise produced atherogenic blood lipid changes (increased TC, increased LDL-C, increased TG, increased Apo B, P < .01) in men with CHD and in healthy men; however, individuals with CHD also demonstrated a significant decrease in HDL-C and Apo AI (P < .01). In contrast, the submaximal physical load improved postprandial lipid changes in both healthy men and men with CHD.

CONCLUSIONS

This study demonstrates that moderate exercise is beneficial in improving postprandial lipid abnormalities in both CHD and CHD-free subjects after fatty meal preload. In addition, maximal exercise demonstrated evidence of increase of lipid abnormalities in both CHD and CHD-free individuals under similar conditions of fatty meal preload.

Evaluation of determinants of walking fitness in patients attending cardiac rehabilitation

AIM

This study aims to investigate the ability of patients' baseline characteristics to predict the distance walked during the incremental shuttle walk test (ISWT) in the cardiac rehabilitation (CR) population and to produce reference values to guide practice.

METHODS

Secondary analysis was conducted on National Audit Cardiac Rehabilitation data collected between 2010 and 2015. Patients (n=8863) were included if they were aged ≥18 years and had a recorded ISWT score assessed before starting CR. Stepwise regression was used to identify factors predicting the ISWT distance. Age, gender, body mass index, height, weight; presence of hypertension, dyslipidemia or diabetes; smoking and physical activity were independent variables. ISWT distance was the dependent variable. The 25th, 50th and 75th percentiles of the ISWT distance were used as reference values.

RESULTS

Age and gender explained 27% of the variance of the distance covered in the ISWT (R2=0.27, adjusted R2=0.27,Standard Error of the Estimate (SEE) = 148.7, p<0.001). Reference values using age and gender categories were developed.

CONCLUSION

Age and gender were the significant factors for predicting the walking fitness in the CR population, with age being the best predictor. The age and gender reference values produced represent a potentially valuable tool to be used in the clinical setting.

Depressive symptoms, functional measures and long-term outcomes of high-risk ST-elevated myocardial infarction patients treated by primary angioplasty

The presence of major depressive symptoms is usually considered a negative long-term prognostic factor after an acute myocardial infarction (AMI); however, most of the supporting research was conducted before the era of immediate reperfusion by percutaneous coronary intervention. The aims of this study are to evaluate if depression still retains long-term prognostic significance in our era of immediate coronary reperfusion, and to study possible correlations with clinical parameters of physical performance. In 184 patients with recent ST-elevated AMI (STEMI), treated by immediate reperfusion, moderate or severe depressive symptoms (evaluated by Beck Depression Inventory version I) were present in 10 % of cases. Physical performance was evaluated by two 6-min walk tests and by a symptom-limited cardiopulmonary exercise test: somatic/affective (but not cognitive/affective) symptoms of depression and perceived quality of life (evaluated by the EuroQoL questionnaire) are worse in patients with lower levels of physical performance. Follow-up was performed after a median of 29 months by means of telephone interviews; 32 major adverse cardiovascular events (MACE) occurred. The presence of three vessels disease and low left ventricle ejection fraction are correlated with a greater incidence of MACE; only somatic/affective (but not cognitive/affective) symptoms of depression correlate with long-term outcomes. In patients with recent STEMI treated by immediate reperfusion, somatic/affective but not cognitive/affective symptoms of depression show prognostic value on long-term MACE. Depression symptoms are not predictors "per se" of adverse prognosis, but seem to express an underlying worse cardiac efficiency, clinically reflected by poorer physical performance.

History of erectile dysfunction as a predictor of poor physical performance after an acute myocardial infarction

Background Erectile dysfunction may predict future cardiovascular events and indicate the severity of coronary artery disease in middle-aged men. The aim of this study was to evaluate whether erectile dysfunction (expression of generalized macro- and micro-vascular pathology) could predict reduced effort tolerance in patients after an acute myocardial infarction. Patients and methods One hundred and thirty-nine male patients (60 ± 12 years old), admitted to intensive cardiac rehabilitation 13 days after a complicated acute myocardial infarction, were evaluated for history of erectile dysfunction using the International Index of Erectile Function questionnaire. Their physical performance was assessed by means of two six-minute walk tests (performed two weeks apart) and by a symptom limited cardiopulmonary exercise test (CPET). Results Patients with erectile dysfunction (57% of cases) demonstrated poorer physical performance, significantly correlated to the degree of erectile dysfunction. After cardiac rehabilitation, they walked shorter distances at the final six-minute walk test (490 ± 119 vs. 564 ± 94 m; p < 0.001); at CPET they sustained lower workload (79 ± 28 vs. 109 ± 34 W; p < 0.001) and reached lower oxygen uptake at peak effort (18 ± 5 vs. 21 ± 5 ml/kg per min; p = 0.003) and at anaerobic threshold (13 ± 3 vs.16 ± 4 ml/kg per min; p = 0.001). The positive predictive value of presence of erectile dysfunction was 0.71 for low peak oxygen uptake (<20 ml/kg per min) and 0.69 for reduced effort capacity (W-max <100 W). Conclusions As indicators of generalized underlying vascular pathology, presence and degree of erectile dysfunction may predict the severity of deterioration of effort tolerance in post-acute myocardial infarction patients. In the attempt to reduce the possibly associated long-term risk, an optimization of type, intensity and duration of cardiac rehabilitation should be considered.

Factors Influencing the Efficacy of Aerobic Exercise for Improving Fitness and Walking Capacity After Stroke: A Meta-Analysis With Meta-Regression

OBJECTIVE

To assess the influence of dosing parameters and patient characteristics on the efficacy of aerobic exercise (AEX) poststroke.

DATA SOURCES

A systematic review was conducted using PubMed, MEDLINE, Cumulative Index of Nursing and Allied Health Literature, Physiotherapy Evidence Database, and Academic Search Complete.

STUDY SELECTION

Studies were selected that compared an AEX group with a nonaerobic control group among ambulatory persons with stroke.

DATA EXTRACTION

Extracted outcome data included peak oxygen consumption (V˙o₂peak) during exercise testing, walking speed, and walking endurance (6-min walk test). Independent variables of interest were AEX mode (seated or walking), AEX intensity (moderate or vigorous), AEX volume (total hours), stroke chronicity, and baseline outcome scores.

DATA SYNTHESIS

Significant between-study heterogeneity was confirmed for all outcomes. Pooled AEX effect size estimates (AEX group change minus control group change) from random effects models were V˙o₂peak, 2.2mL⋅kg^-1⋅min^-1 (95% confidence interval [CI], 1.3-3.1mL⋅kg^-1⋅min^-1); walking speed, .06m/s (95% CI, .01-.11m/s); and 6-minute walk test distance, 29m (95% CI, 15-42m). In meta-regression, larger V˙o₂peak effect sizes were significantly associated with higher AEX intensity and higher baseline V˙o₂peak. Larger effect sizes for walking speed and the 6-minute walk test were significantly associated with a walking AEX mode. In contrast, seated AEX did not have a significant effect on walking outcomes.

CONCLUSIONS

AEX significantly improves aerobic capacity poststroke, but may need to be task specific to affect walking speed and endurance. Higher AEX intensity is associated with better outcomes. Future randomized studies are needed to confirm these results.

What is the impact of impaired left ventricular ejection fraction in COPD after adjusting for confounders?

BACKGROUND

It remains unknown whether and to what extent impaired left ventricular ejection fraction (LVEF) affects physical and psychological status in COPD. We aimed to compare health outcome measures between COPD patients with and without impaired LVEF after adjusting for age, sex, BMI and FEV₁.

METHODS

Impaired LVEF was defined as values <50%. 85 COPD patients with impaired LVEF and 85 COPD patients with normal LVEF were matched for sex, age, BMI and FEV₁. Exercise capacity, quadriceps muscle function, functional mobility, inflammatory status, health status, care dependency, and mood disorders were cross-sectionally assessed.

RESULTS

Patients with impaired LVEF had shorter 6-minute walk distance (mean -59 (95% confidence interval: -94, -25)m), lower symptom-limited peak oxygen uptake (-131 (-268, 7)ml/min), weaker quadriceps muscles (-12 (-20, -3)Nm) and had more symptoms of anxiety (+2 (1, 3) points) and depression (+1 (0, 2) points) than those with normal LVEF (all P<0.05). Health status was not statistically different between groups (P>0.05).

CONCLUSIONS

Impaired LVEF has a clear impact on physical and psychological status in patients with COPD, even after adjusting for confounders. This reinforces the importance of assessing and treating cardiac problems in COPD.

High-Intensity Interval Training and Moderate-Intensity Continuous Training in Ambulatory Chronic Stroke: Feasibility Study

BACKGROUND

Poststroke guidelines recommend moderate-intensity, continuous aerobic training (MCT) to improve aerobic capacity and mobility after stroke. High-intensity interval training (HIT) has been shown to be more effective than MCT among healthy adults and people with heart disease. However, HIT and MCT have not been compared previously among people with stroke.

OBJECTIVE

The purpose of this study was to assess the feasibility and justification for a definitive randomized controlled trial (RCT) comparing HIT and MCT in people with chronic stroke.

DESIGN

A preliminary RCT was conducted.

SETTING

The study was conducted in a cardiovascular stress laboratory and a rehabilitation research laboratory.

PATIENTS

Ambulatory people at least 6 months poststroke participated.

INTERVENTION

Both groups trained 25 minutes, 3 times per week, for 4 weeks. The HIT strategy involved 30-second bursts at maximum-tolerated treadmill speed alternated with 30- to 60-second rest periods. The MCT strategy involved continuous treadmill walking at 45% to 50% of heart rate reserve.

MEASUREMENTS

Measurements included recruitment and attendance statistics, qualitative HIT acceptability, adverse events, and the following blinded outcome variables: peak oxygen uptake, ventilatory threshold, metabolic cost of gait, fractional utilization, fastest treadmill speed, 10-Meter Walk Test, and Six-Minute Walk Test.

RESULTS

During the 8-month recruitment period, 26 participants consented to participate. Eighteen participants were enrolled and randomly assigned to either the HIT group (n=13) or the MCT group (n=5). Eleven out of the 13 HIT group participants attended all sessions. Participants reported that HIT was acceptable and no serious adverse events occurred. Standardized effect size estimates between groups were moderate to very large for most outcome measures. Only 30% of treadmill speed gains in the HIT group translated into overground gait speed improvement.

LIMITATIONS

The study was not designed to definitively test safety or efficacy.

CONCLUSIONS

Although further protocol optimization is needed to improve overground translation of treadmill gains, a definitive RCT comparing HIT and MCT appears to be feasible and warranted.

Functional parameters but not heart rate variability correlate with long-term outcomes in St-elevation myocardial infarction patients treated by primary angioplasty

BACKGROUND

Depressed heart rate variability (HRV) is usually considered a negative long-term prognostic factor after acute myocardial infarction. Anyway, most of the supporting research was conducted before the era of immediate reperfusion by percutaneous coronary intervention (PCI). Main aim of this study was to evaluate if HRV still retains prognostic significance in our era of immediate PCI.

METHODS AND RESULTS

Two weeks after STEMI treated by primary PCI, time-domain HRV was assessed from 24-h Holter recordings in 186 patients: markedly depressed HRV (SDNN <70ms or <50ms) was present in 16% and in 5% of cases, respectively; patients with left ventricle ejection fraction (LVEF) <40% presented more often SDNN values in the lowest quartile. Physical performance was also assessed, by 6-minute walk tests (6MWT) and by cardiopulmonary exercise test (CPET). After >2years from infarction, occurrence of major clinical events (MCE) was investigated. Cases with or without MCE did not differ by initial HRV parameters; Kaplan-Meier events-free survival curves were similar between patients with lowest quartile SDNN and the remaining ones (χ² 0.981, p=0.322). By the contrary, events-free survival was worse if patients walked shorter distances at 6MWT (χ² 6.435, p=0.011), developed poorer ventilatory efficiency at CPET (χ² 10.060, p=0.002), or presented LVEF <40% (χ² 7.085, p=0.008).

CONCLUSIONS

In primary-PCI STEMI patients, markedly abnormal HRV was found in a small percentage of cases. HRV seems to have lost its prognostic significance, while parameters indicating LV function (LVEF and physical performance) could allow better prognostication in primary-PCI STEMI patients.

Ventilatory threshold may be a more specific measure of aerobic capacity than peak oxygen consumption rate in persons with stroke

BACKGROUND

After stroke, aerobic deconditioning can have a profound impact on daily activities. This is usually measured by the peak oxygen consumption rate achieved during exercise testing (VO2-peak). However, VO2-peak may be distorted by motor function. The oxygen uptake efficiency slope (OUES) and VO2 at the ventilatory threshold (VO2-VT) could more specifically assess aerobic capacity after stroke, but this has not been tested.

OBJECTIVES

To assess the differential influence of motor function on three measures of aerobic capacity (VO2-peak, OUES, and VO2-VT) and to evaluate the inter-rater reliability of VO2-VT determination post-stroke.

METHODS

Among 59 persons with chronic stroke, cross-sectional correlations with motor function (comfortable gait speed [CGS] and lower extremity Fugl-Meyer [LEFM]) were compared between the different aerobic capacity measures, after adjustment for covariates, in order to isolate any distorting effect of motor function. Reliability of VO2-VT determination between three raters was assessed with intra-class correlation (ICC).

RESULTS

CGS was moderately correlated with VO2-peak (r = 0.52, p < 0.0001) and weakly correlated with OUES (r = 0.41, p = 0.002) and VO2-VT (r = 0.37, p = 0.01). LEFM was weakly correlated with VO2-peak (r = 0.26, p = 0.055) and very weakly correlated with OUES (r = 0.19, p = 0.17) and VO2-VT (r = 0.14, p = 0.31). Compared to VO2-peak, VO2-VT was significantly less correlated with CGS (r difference = -0.16, p = 0.02). Inter-rater reliability of VO2-VT determination was high (ICC: 0.93, 95% CI: 0.89-0.96).

CONCLUSIONS

Motor dysfunction appears to artificially lower measured aerobic capacity. VO2-VT seemed to be less distorted than VO2-peak and had good inter-rater reliability, so it may provide more specific assessment of aerobic capacity post-stroke.

Relationship Between Exercise Workload During Cardiac Rehabilitation and Outcomes in Patients With Coronary Heart Disease

The purpose of this retrospective, observational study was to describe the relation between exercise workload during cardiac rehabilitation (CR), expressed as metabolic equivalents of task (METs), and prognosis among patients with coronary heart disease. We included patients with coronary heart disease who participated in CR between January 1998 and June 2007. METs were calculated from treadmill workload. Cox regression analysis was used to describe the relationship between METs and time to a composite outcome of all-cause mortality, nonfatal myocardial infarction, or heart failure hospitalization. Among 1,726 patients (36% women; median age 59 years [interquartile range, 52 to 66]), there were 467 events (27%) during a median follow-up of 5.8 years (interquartile range, 2.6 to 8.7). In analyses adjusted for age, sex, Charlson co-morbidity index, hypertension, diabetes, and CR referral diagnosis, METs were independently related to the composite outcome at CR start (Wald chi-square 43, hazard ratio 0.59 [95% confidence interval 0.51 to 0.70]) and CR end (Wald chi-square 47, hazard ratio 0.68 [95% confidence interval 0.61 to 0.76]). Patients exercising below 3.5 METs on exit from CR represent a high-risk group with 1- and 3-year event rates ≥7% and ≥18%, respectively. In conclusion, METs during CR is available at no additional cost and can be used to identify patients at increased risk for an event who may benefit from closer follow-up, extended length of stay in CR, and/or participation in other strategies aimed at maximizing adherence to secondary preventive behaviors and improving exercise capacity.

Effect of High Interval Training in Acute Myocardial Infarction Patients with Drug-Eluting Stent

OBJECTIVE

Peak oxygen uptake (VO2peak) is a strong predictor of survival in cardiac patients. The aims of this study were to compare the effects of high interval training (HIT) to moderate continuous training (MCT) on VO2peak and to identify the safety of HIT in acute myocardial infarction patients with drug-eluting stent.

DESIGN

Twenty-eight acute myocardial infarction patients with drug-eluting stent were randomized to either HIT at 85%-95 % of heart rate reserve or MCT at 70%-85% of heart rate reserve, 3 days a week for 6 wks at a cardiac rehabilitation clinic. Primary outcome was VO2peak at baseline and after cardiac rehabilitation.

RESULTS

Both HIT and MCT groups showed significant increases in VO2peak and heart rate recovery after 6 wks of training. The 22.16% improvement in VO2peak in the HIT group was significantly greater than the 8.48% improvement in the MCT group (P = 0.021). There were no cardiovascular events related to both HIT and MCT.

CONCLUSIONS

HIT is more effective than MCT for improving VO2peak in acute myocardial infarction patients with drug-eluting stent. These findings may have important implications for more effective exercise training in cardiac rehabilitation program.

Determining target heart rate for exercising in a cardiac rehabilitation program: a retrospective study

BACKGROUND

One of the well-established methods used to determine endurance training intensity for patients in outpatient cardiac rehabilitation (CR) is to take a percentage (70%-85%) of the maximal or peak heart rate (HRmax) from a recent postevent symptom-limited graded exercise test (GXT). Because many patients are referred to CR without having had a maximal GXT, a current practice is to use 30% to 50% above resting heart rate (RHR) to estimate endurance training intensity.

OBJECTIVE

The purpose of this study was to determine if a target heart rate (THR) of 30% to 50% above RHR approximated a THR of 70% to 85% of the HRmax achieved on GXT (HRmax GXT) and provided equivalent exercise intensity based on ratings of perceived exertion (RPE) and metabolic equivalency thresholds (METs).

METHODS

A retrospective chart review of 53 patients enrolled in CR and had documentation of postevent GXT was conducted to determine the patient's mean exercise heart rate (HR) achieved at each session to percentage above RHR and percentage HRmax GXT. Analysis was conducted to determine and compare patients' HRs, RPE, and MET levels when patients were exercising within the THR ranges of 30% to 50% above RHR and 70% to 85% HRmax GXT.

RESULTS

A THR range of 30% to 50% above RHR approximated 60% to 70% HRmax GXT. Mean exercise HRs progressed from 39% to 49% above RHR sessions 2 to 6 with mean (SD) RPE of 10.58 (0.55) to 11.44 (0.68) on the Borg scale and mean (SD) MET level of 2.91 (0.55) to 3.31 (0.6). Mean exercise HRs progressed to 54% to 65% above RHR sessions 7 to 18 and approximated 70% to 73% HRmax GXT. Mean (SD) RPE at this intensity ranged from 11.57 (0.58) to 12.21 (0.53) with a mean (SD) MET level of 3.47 (0.6) to 3.8 (0.77).

CONCLUSION

In the observed population, a THR of 30% to 50% above RHR underestimated the THR range of 70% to 85% HRmax GXT but provided adequate exercise intensity for patients at the beginning of a CR program based on percentage HRmax GXT, RPE and MET levels.

Evidence that the talk test can be used to regulate exercise intensity

The Talk Test (TT) has been shown to be a surrogate of the ventilatory threshold and to be a viable alternative to standard methods of prescribing exercise training intensity. The TT has also been shown to be responsive to manipulations known to change physiologic function including blood donation and training. Whether the TT can be used independently to regulated training intensity is not known. Physically active volunteers (N = 16) performed an incremental exercise test to identify stages of the TT (Last Positive [LP], Equivocal [EQ], and Negative [NEG]). In subsequent, randomly ordered, 30-minute steady-state runs, the running velocity was regulated solely by "clamping" the TT response desired and then monitoring the response of conventional markers of exercise intensity (heart rate, blood lactate, rating of perceived exertion). All subjects were able to complete the LP stage, but only 13 of 16 and 2 of 16 subjects were able to complete the EQ and NEG stages, respectively. Physiologic responses were broadly within those predicted from the incremental exercise test and within the appropriate range of physiologic responses for exercise training. Thus, in addition to correlating with convenient physiological markers, the TT can be used proactively to guide exercise training intensity. The LP stage produced training intensities compatible with appropriate training intensity in healthy adults and with recovery sessions or long duration training sessions in athletes. The EQ and NEG stages produced intensities compatible with higher intensity training in athletes. The results demonstrate that the TT can be used as a primary method to control exercise training intensity.

Predicting Heart Rate at the Ventilatory Threshold for Aerobic Exercise Prescription in Persons With Chronic Stroke

BACKGROUND AND PURPOSE

Treadmill aerobic exercise improves gait, aerobic capacity, and cardiovascular health after stroke, but a lack of specificity in current guidelines could lead to underdosing or overdosing of aerobic intensity. The ventilatory threshold (VT) has been recommended as an optimal, specific starting point for continuous aerobic exercise. However, VT measurement is not available in clinical stroke settings. Therefore, the purpose of this study was to identify an accurate method to predict heart rate at the VT (HRVT) for use as a surrogate for VT.

METHODS

A cross-sectional design was employed. Using symptom-limited graded exercise test (GXT) data from 17 subjects more than 6 months poststroke, prediction methods for HRVT were derived by traditional target HR calculations (percentage of HRpeak achieved during GXT, percentage of peak HR reserve [HRRpeak], percentage of age-predicted maximal HR, and percentage of age-predicted maximal HR reserve) and by regression analysis. The validity of the prediction methods was then tested among 8 additional subjects.

RESULTS

All prediction methods were validated by the second sample, so data were pooled to calculate refined prediction equations. HRVT was accurately predicted by 80% HRpeak (R, 0.62; standard deviation of error [SDerror], 7 bpm), 62% HRRpeak (R, 0.66; SDerror, 7 bpm), and regression models that included HRpeak (R, 0.62-0.75; SDerror, 5-6 bpm).

DISCUSSION AND CONCLUSIONS

Derived regression equations, 80% HRpeak and 62% HRRpeak, provide a specific target intensity for initial aerobic exercise prescription that should minimize underdosing and overdosing for persons with chronic stroke. The specificity of these methods may lead to more efficient and effective treatment for poststroke deconditioning.Video Abstract available for more insights from the authors (see Supplemental Digital Content 1, http://links.lww.com/JNPT/A114).

Graded Exercise Testing Versus Simulated Competition Exercise in Trained Older Males

PURPOSE

Exercise-based rehabilitation is a standard therapy for patients with heart disease. Despite examples of patients who have extended normal rehabilitation exercise into competitive participation, there are no clear-cut guidelines for patients whether they should participate in competitive-level exercise. This study investigated the occurrence of complications, physiologic responses, and exercise patterns during simulated competitive exercise in active, older nonathletes (most with a history of cardiovascular disease) and compared these with responses during maximal incremental exercise.

METHODS

Fourteen trained older males, 7 with stable cardiovascular disease, performed an incremental exercise test and time trial of 55 kJ (equivalent to running ∼1 mile) on a semirecumbent stepping ergometer. Variables of gas exchange, hemodynamics, perception, and power output were measured in both tests.

RESULTS

Subjects attained a remarkably high physiologic and psychologic strain (respiratory exchange ratio >1.0; average peak rating of perceived exertion >8) in both tests, with no evidence of symptomatic, hemodynamic, or electrocardiographic abnormalities. Peak physiologic responses were not significantly different between simulated competition and incremental exercise. The fixed-work time trial was finished in 8.97 ± 1.85 minutes, mean power output of 100 ± 26 W. Results showed a distinct pacing pattern in the relative power output, consisting of a conservative start, an even-paced middle portion, and an end spurt.

CONCLUSIONS

Results suggest that in trained individuals with normal incremental exercise test results, competitive-level efforts may be undertaken with no apparent side effects. This may provide a strategy whereby physicians can advise patients concerning their decision to perform in competitive events.

Does aerobic exercise and the FITT principle fit into stroke recovery?

Sedentary lifestyle after stroke is common which results in poor cardiovascular health. Aerobic exercise has the potential to reduce cardiovascular risk factors and improve functional capacity and quality of life in people after stroke. However, aerobic exercise is a therapeutic intervention that is underutilized by healthcare professionals after stroke. The purpose of this review paper is to provide information on exercise prescription using the FITT principle (frequency, intensity, time, type) for people after stroke and to guide healthcare professionals to incorporate aerobic exercise into the plan of care. This article discusses the current literature outlining the evidence base for incorporating aerobic exercise into stroke rehabilitation. Recently, high-intensity interval training has been used with people following stroke. Information is provided regarding the early but promising results for reaching higher target heart rates.

Evidence for distinct effects of exercise in different cardiac hypertrophic disorders

Aerobic exercise training (AET) attenuates or reverses pathological cardiac remodeling after insults such as chronic hypertension and myocardial infarction. The phenotype of the pathologically hypertrophied heart depends on the insult; therefore, it is likely that distinct types of pathological hypertrophy require different exercise regimens. However, the mechanisms by which AET improves the structure and function of the pathologically hypertrophied heart are not well understood, and exercise research uses highly inconsistent exercise regimens in diverse patient populations. There is a clear need for systematic research to identify precise exercise prescriptions for different conditions of pathological hypertrophy. Therefore, this review synthesizes existing evidence for the distinct mechanisms by which AET benefits the heart in different pathological hypertrophy conditions, suggests strategic exercise prescriptions for these conditions, and highlights areas for future research.

Influence of exercise modality on agreement between gas exchange and heart rate variability thresholds

The main purpose of this study was to investigate the level of agreement between the gas exchange threshold (GET) and heart rate variability threshold (HRVT) during maximal cardiopulmonary exercise testing (CPET) using three different exercise modalities. A further aim was to establish whether there was a 1:1 relationship between the percentage heart rate reserve (%HRR) and percentage oxygen uptake reserve (%VO2 R) at intensities corresponding to GET and HRVT. Sixteen apparently healthy men 17 to 28 years of age performed three maximal CPETs (cycling, walking, and running). Mean heart rate and VO2 at GET and HRVT were 16 bpm (P<0.001) and 5.2 mL · kg(-1) · min(-1) (P=0.001) higher in running than cycling, but no significant differences were observed between running and walking, or cycling and walking (P>0.05). There was a strong relationship between GET and HRVT, with R2 ranging from 0.69 to 0.90. A 1:1 relationship between %HRR and % VO2 R was not observed at GET and HRVT. The %HRR was higher during cycling (GET mean difference=7%; HRVT mean difference=11%; both P<0.001), walking (GET mean difference=13%; HRVT mean difference=13%; both P<0.001), or running (GET mean difference=11%; HRVT mean difference=10%; both P<0.001). Therefore, using HRVT to prescribe aerobic exercise intensity appears to be valid. However, to assume a 1:1 relationship between %HRR and % VO2 R at HRVT would probably result in overestimation of the energy expenditure during the bout of exercise.