Peak oxygen uptake prediction from a moderate, perceptually regulated, 1-km treadmill walk in male cardiac patients

Change in Peak Oxygen Uptake Predicted by the Moderate 1-km Treadmill Walking Test After Walking Training in Outpatients With Cardiovascular Disease

PURPOSE

The purpose of this study was to determine the ability of the moderate 1-km treadmill walking test (1km-TWT) to predict changes in peak oxygen uptake (V˙O 2peak ) in patients with stable cardiovascular disease (CVD) during an exercise-based secondary prevention program.

METHODS

Sixty-four male outpatients with stable CVD (age 64 [41-85] yr) performed the 1km-TWT before and after an 8-wk walking training program. Patient V˙O 2peak was estimated using a sex-specific equation including age, body mass index, 1km-TWT performance time, and heart rate (V˙O 2peakEST ). Forty-one patients completed a maximal cardiopulmonary treadmill test (CPX) for direct V˙O 2peak determination (V˙O 2peakMEAS ). The training prescription consisted of moderate-to-high intensity supervised walking for 30-40 min/session, and an additional 2-4 times/wk of unsupervised home moderate walking sessions between 20-60 min at the end of the program. The walking intensity was based on the results of the 1km-TWT.

RESULTS

Patients participated in an average of 14 of the 16 supervised sessions. An overall significant improvement in V˙O 2peakMEAS and weekly recreational physical activity levels were observed. No differences were observed between V˙O 2peakMEAS and V˙O 2peakEST . Compared with CPX results, the 1km-TWT underestimated the V˙O 2peak increase after the exercise intervention (mean difference -0.3 mL/kg/min, P > .05).

CONCLUSIONS

The 1km-TWT provides a reasonably accurate and simple tool to predict changes in V˙O 2peak due to moderate walking training in male outpatients with CVD. These findings contribute to the growing body of evidence supporting the use of the 1km-TWT for exercise testing and training purposes in the context of cardiac rehabilitation/secondary prevention programs.

Full Familiarisation Is Not Required for the Self-Paced 1 km Treadmill Walk to Predict Peak Oxygen Uptake in Phase IV Cardiac Patients

Exercise is a recommended part of phase IV cardiovascular rehabilitation (CR). The 1 km treadmill walk test (1-KTWT) is a submaximal continuous exercise test to predict cardiorespiratory fitness in patients with cardiovascular disease. We examined physiological, metabolic and subjective responses in patients with cardiovascular disease with self-selected, unchanging walking speed for two 1-KTWTs. Fifteen men (age: 65 ± 9 yr, height: 174 ± 5 cm, body mass: 86 ± 17 kg, BMI: 28.5 ± 5.5 kg·m-2, body fat%: 27.7 ± 7.5%, 10 on beta-blockers) were recruited from phase IV CR groups in the United Kingdom. Participants established a self-selected walking speed for the 1-KTWT and performed the 1-KTWT on separate days with recording of physiological responses to predict V˙O2peak with equations. For the two 1-KTWTs, no differences existed for walking speed, mean and maximal heart rates, oxygen uptake, predicted V˙O2peak (1st 1-KTWT (range: 41-78% V˙O2peak, 95%CI, 53-65; 2nd 1-KTWT range: 43-78% V˙O2peak, 95%CI, 52-65) and rating of perceived exertion. In phase IV cardiac patients, the 1-KTWT with self-selected, unchanging walking speed can be used for V˙O2peak prediction without the need for a full familiarisation. The self-selected constant walking speed for the first 1-KTWT can be used to support nonsupervised physical activity for phase IV CR patients.

A Moderate Walking Test Predicts Survival in Women With Cardiovascular Disease

INTRODUCTION

Cardiovascular disease (CVD) is the principal cause of death in U.S. women. Peak oxygen uptake is strongly related to mortality and CVD. This study aimed to investigate the association between estimated peak oxygen uptake, determined using a moderate 1-km walking test, and all-cause mortality in female patients with stable CVD.

METHODS

Of the 482 women in our registry between 1997 and 2020, we included 430 participants in the analysis (aged 67 [34-88] years). A Cox proportional hazard model was used to determine the variables significantly associated with mortality. On the basis of the peak oxygen uptake estimated using the 1-km walking test, the sample was subdivided into tertiles, and mortality risk was calculated. The discriminatory accuracy of peak oxygen uptake in estimating survival was assessed by receiver operating characteristic curves. All results were adjusted for demographic and clinical covariates.

RESULTS

A total of 135 deaths from any cause occurred over a median of 10.4 years (IQR=4.4-16.4), with an average annual mortality of 4.2%. Estimated peak oxygen uptake was a stronger predictor of all-cause mortality than demographic and clinical variables (c-statistic-0.767; 95% CI=0.72, 0.81; p<0.0001). The survival rate decreased from the highest tertile of fitness to the lowest. Compared with the lowest group, hazard ratios (95% CIs) for the second and third tertiles were 0.55 (0.37, 0.83) and 0.29 (0.16, 0.51), respectively (p for trend <0.0001).

CONCLUSIONS

Higher peak oxygen uptake levels were associated with a lower risk of all-cause mortality. The indirect estimation of peak oxygen uptake using the 1-km walking test is feasible and can be applied for risk stratification among female patients undergoing secondary prevention programs.

Experience and Perceptions among Older Outpatients after Myocardial Infarction following an Exercise Intervention: A Qualitative Analysis from the PIpELINe Trial

Traditional cardiac rehabilitation (CR) programs effectively improve physical performance and outcomes after myocardial infarction (MI). However, older patients are less likely to participate in such programs. The aim of this qualitative analysis was to investigate experiences and perceptions of cardiac outpatients enrolled in an innovative and exercise-based CR program and to identify possible barriers to improving adherence and quality of life. Semi-structured interviews were conducted on a sample of 31 patients (84% male; age 76 ± 6 years) from the Physical Activity Intervention in Elderly after Myocardial Infarction (PIpELINe) trial, after about six months of the event. Three main themes were identified: Personal feelings after the event; lifestyle change and perception of barriers; and relationships with familiars. Participants perceived sensations of fear at the time of their diagnosis and showed awareness of the importance of following specific health suggestions. They reported a significative change in previous habits and highlighted the need for periodic controls. Few of them felt insecure in carrying out daily activities or practicing exercise and reported an unnecessary protection from the family members. These findings will provide valuable insights for the development of a more feasible patient-centered CR model of intervention.

Moderate walking speed and survival association across 23-years follow-up in female patients with cardiovascular disease

AIMS

To estimate the association between average walking speed (WS), determined using a moderate 1-km treadmill-walking test (1 k-TWT), and all-cause mortality in female patients with stable cardiovascular disease (CVD).

METHODS

A sample of 431 patients (age 67 [34-88] years), performed a 1 k-TWT and were followed for all-cause mortality for up to 23 years. Variables significantly associated with mortality were determined by Cox proportional hazard models. Based on average WS during the 1k_TWT the sample was subdivided into tertiles, and mortality risk was calculated. Receiver-operating-characteristic curves were constructed to assess the discriminatory accuracy of WS for estimating survival.

RESULTS

During a median follow-up of 10.4 years, a total of 135 deaths from any cause occurred, with an average mortality rate of 4.2%. The strongest predictor of mortality was WS (c-statistic for all-cause mortality 0.801, 95% confidence intervals: 0.51-1.11, p < 0.0001). Survival rate decreased from the fastest to the lowest tertile. Compared to the group with the lowest WS, the hazard ratios (95% confidence intervals) for the second and third tertiles were 0.73 (0.48-1.12) and 0.47 (0.25-0.91), respectively (p for trend <0.0001).

CONCLUSION

Average WS maintained during a moderate treadmill-walk is inversely related to survival in female patients with CVD. The 1 k-TWT is a simple and useful tool for assessing progress and stratifying risk in women undergoing secondary prevention programs.

Valorization of natural cardio trekking trails through open innovation for promotion of sustainable cross-generational, health-oriented tourism during the Connect2Move project: study design (Preprint)

Background

Hiking is one of the most popular forms of exercise in the alpine region. However, besides its health benefits, hiking is the alpine activity with the highest incidence of cardiac events. Most incidents occur due to overexertion or underestimation of the physiological strain of hiking.

Objective

This project will establish a standardized cardio trekking test trail to evaluate the exercise capacity of tourists within hiking areas and deliver a tool for the prevention of hiking-associated cardiac incidents. Further, individual exercise intensity for a hiking tour will be predicted and visualized in digital maps.

Methods

This cooperation study between Austria and Germany will first validate a 1-km outdoor cardio trekking test trail at 2 different study sites. Then, exercise intensity measures on 8-km hiking trails will be evaluated during hiking to estimate overall hiking intensity. A total of 144 healthy adults (aged >45 years) will perform a treadmill test in the laboratory and a 1-km hiking test outdoors. They will wear a portable spirometry device that measures gas exchange, as well as heart rate, walking speed, ventilation, GPS location, and altitude throughout the tests. Estimation models for exercise capacity based on measured parameters will be calculated.

Results

The project “Connect2Move” was funded in December 2019 by the European Regional Development Fund (INTERREG V-A Programme Austria-Bavaria – 2014-2020; Project Number AB296). “Connect2Move” started in January 2020 and runs until the end of June 2022. By the end of April 2022, 162 participants were tested in the laboratory, and of these, 144 were tested outdoors. The data analysis will be completed by the end of June 2022, and results are expected to be published by the end of 2022.

Conclusions

Individual prediction of exercise capacity in healthy individuals with interest in hiking aims at the prevention of hiking-associated cardiovascular events caused by overexertion. Integration of a mathematical equation into existing hiking apps will allow individual hiking route recommendations derived from individual performance on a standardized cardio trekking test trail.

Trial Registration

ClinicalTrails.gov NCT05226806; https://clinicaltrials.gov/ct2/show/NCT05226806

International Registered Report Identifier (IRRID)

DERR1-10.2196/39038

Maintenance of Exercise Habit and Its Impact on Cardiovascular Risk Factors in Previously Sedentary People: A 7-Year Follow-Up

The aim of the study was to assess whether the level of physical activity in daily life in previously sedentary adults had been sustained 7 years beyond a 1-year supervised walking program. One hundred ten participants (63 females, 57.5 ± 8.4 years; 47 males, 66.4 ± 7.9 years) were recalled and assessed for physical activity in daily life, weight, body mass index, blood pressure, and walking speed. Fifty-nine percentage of the participants measured met and exceeded the World Health Organization physical activity guidelines (Group 1), while 41% did not (Group 2). In both groups, we observed a significant decrease of weight (72.0 ± 14.0 kg vs. 69.7 ± 14.0 kg in Group 1; 77.4 ± 19.5 kg vs. 75.4 ± 18.6 kg in Group 2) and body mass index (25.9 ± 3.7 vs. 25.1 ± 3.9 in Group 1; 27.9 ± 5.6 vs. 27.2 ± 5.4 in Group 2). Group 1 showed a significant increase in walking speed (5.8 ± 0.7 km/hr vs. 6.2 ± 0.8 km/hr), while systolic pressure did not change from the baseline. In Group 2, systolic pressure significantly increased (131.3 ± 13.5 mmHg vs. 138.0 ± 15.5 mmHg), while walking speed did not change. A guided walking program seems to have been effective in educating sedentary people to remain physically active over time.

Adherence to a guided walking program with amelioration of cognitive functions in subjects with schizophrenia even during COVID-19 pandemic

Background

Aim of the study was to enrol a group of individuals with schizophrenia in a long-term moderate-intensity physical activity program and to evaluate its effects on their cognitive functions and cardiovascular risk factors. An additional aim of the study was the comparison of the adherence to the physical activity program before and during the COVID-19 pandemic.

Methods

Forty sedentary patients diagnosed with schizophrenia (mean age 46.4 ± 9.6) followed by the Public Mental Health Department of Ferrara were included in the study. 28 of them followed a 1-year walking program consisting of two guided walking sessions/week, while 12 maintained their sedentary lifestyle and followed the usual Cognitive Rehabilitation program. To the participants following the walking program VO₂ peak and walking speed were assessed at baseline and at the end of the program. All participants were evaluated on blood pressure and anthropometric variable. Cognitive functions were assessed with the Screen for Cognitive Impairment in Psychiatry (SCIP) and with the Frontal Assessment Battery (FAB) questionnaires.

Results

The 20 participants completing the walking program displayed significant improvements in cognitive functions (d_ppc2 0.35 for SCIP and 0.26 for FAB), with a positive correlation between SCIP score and the number of sessions attended (R = 0.86, p < 0.001), evident in the patients attending to at least 75 of the 100 walking sessions. Walking speed and VO₂peak increased significantly and a decrease of body weight, BMI, systolic and diastolic blood pressure was also observed. The adherence to the walking program registered during Covid-19 period did not differ from that observed before the pandemic. The 12 CG (Control Group) patients maintaining the sedentary lifestyle did not display improvements of cognitive functions.

Conclusions

The main finding of this study is the improvement of cognitive functions which is significantly related to the number of walking sessions attended by participants with schizophrenia. The walking program, guided by exercise specialists, proved to be an enjoyable activity for people with mental disorder feasible even during the COVID-19 pandemic.

Trial registration Retrospectively registered on ISRCTN as non-randomized trial (n. ISRCTN14763786).

Improving walking speed reduces hospitalization costs in outpatients with cardiovascular disease. An analysis based on a multistrata non-parametric test

BACKGROUND

To assess the association between walking speed (WS) and its improvement on hospitalization rates and costs in outpatients with cardiovascular disease.

METHODS

Six hundred forty-nine patients participating in an exercise-based secondary prevention program were studied. Patients were divided at baseline into two groups characterized by low and high WS based on the average WS maintained during a moderate 1-km treadmill-walking test. WS and other covariates were grouped into three domains (demographic factors, medical history and risk factors), and used to estimate a propensity score, in order to create homogeneous groups of patients. All-cause hospitalization was assessed 3 years after baseline as a function of WS. Hospitalization and related costs were also assessed during the fourth-to-sixth years after enrollment. To test whether the hospitalization costs were related to changes in WS after 36 months, a multistrata permutation test was performed by combining within strata partial tests.

RESULTS

The results support the hypothesis that hospitalization costs are significantly reduced in accordance with an improvement in WS. This effect is most evident among older patients, overweight or obese, smokers, and those without a history of coronary artery bypass surgery.

CONCLUSIONS

The present study supports growing evidence of an inverse association between WS, risk of hospitalization and consequent health-care costs. The joint use of propensity score and multistrata permutation approaches represent a flexible and robust testing method which avoids the possible effects of several confounding factors typical of these studies.

A moderate 200-m walk test estimates peak oxygen uptake in elderly outpatients with cardiovascular disease

BACKGROUND

A moderate 1-km treadmill walk test (1k-TWT) has been demonstrated to be a valid tool for estimating peak oxygen uptake (VO2peak) in outpatients with cardiovascular disease (CVD). The results obtained by the 1k-TWT predict survival and hospitalization in men and women with CVD. We aimed to examine whether shorter versions of the full 1k-TWT equally assess VO2peak in outpatients with CVD.

METHODS

One hundred eighteen outpatients with CVD, aged 70±9 years, referred to an exercise-based secondary prevention program, performed a moderate and perceptually-regulated (11-13/20 on the Borg Scale) 1k-TWT. Age, height, weight, heart rate, time to walk 100-m, 200-m, 300-m, and 400-m, and the full 1000-m, were entered into equations to estimate VO2peak.

RESULTS

The minimal distance providing similar VO2peak results of the full 1k-TWT was 200-m: 23.0±5.3 mL/kg/min and 23.0±5.5 mL/kg/min, respectively. The concordance correlation coefficient between the two was 0.97 (95%CI 0.96 to 0.98, P<0.0001). The slope and the intercept of the relationship between the values obtained by the 200-m and the full 1k-TWT were not different from the line of identity. Bland-Altman analysis did not show systematic or proportional error.

CONCLUSIONS

A moderate 200-m treadmill-walk is a reliable method for estimating VO2peak in elderly outpatients with CVD. A 200-m walk enables quick and easy cardiorespiratory fitness assessment, with low costs and low burden for health professionals and patients. These findings have practical implications for the transition of patients from clinically-based programs to fitness facilities or self-guided exercise programs.

Impact of Improvement in Walking Speed on Hospitalization and Mortality in Females with Cardiovascular Disease

Cardiovascular disease (CVD) is the principal cause of death in women. Walking speed (WS) is strongly related with mortality and CVD. The rate of all-cause hospitalization or death was assessed in 290 female outpatients with CVD after participation in a cardiac rehabilitation/secondary prevention program (CR/SP) and associated with the WS maintained during a moderate 1 km treadmill-walk. Three-year mortality rates were 57%, 44%, and 29% for the slow (2.1 ± 0.4 km/h), moderate (3.1 ± 0.3 km/h), and fast (4.3 ± 0.6 km/h) walkers, respectively, with adjusted hazard ratios (HRs) of 0.78 (p = 0.24) and 0.55 (p = 0.03) for moderate and fast walkers compared to the slow walkers. In addition, hospitalization or death was examined four to six years after enrollment as a function of the change in the WS of 176 patients re-assessed during the third year after baseline. The rates of hospitalization or death were higher across tertiles of reduced WS, with 35%, 50%, and 53% for the high (1.5 ± 0.3 km/h), intermediate (0.7 ± 0.2 km/h), and low tertiles (0.2 ± 0.2 km/h). Adjusted HRs were 0.79 (p = 0.38) for the intermediate and 0.47 (p = 0.02) for the high tertile compared to the low improvement tertile. Improved walking speed was associated with a graded decrease in hospitalization or death from any cause in women undergoing CR/SP.

Guided walking reduces blood pressure in hypertensive sedentary subjects including those with resistant hypertension

Hypertension poorly responsive to medications is defined resistant hypertension. We have previously shown that 1-year of guided walking is followed by highly significant reduction of systolic blood pressure in hypertensive subjects. Aim of this study was to assess the effect of a 1-year of guided walking on the blood pressure of sedentary hypertensive subjects including patients with resistant hypertension. Two hundred and fifty-nine sedentary subjects with systolic pressure ≥130 mmHg were subdivided in a group without blood pressure medications and in a group taking three or more antihypertensive drugs, including diuretics. Blood pressure, body weight, body mass index, waist circumference, and walking speed were determined at enrollment and after 1-year of walking, supervised by exercise physiologists. At baseline, systolic pressure was significantly higher in the subjects under therapy (144.6 ± 12.2 vs. 140.2 ± 10.7). Two hundred and three subjects (124 without and 79 with therapy) completed the program. During the 1-year program each subject walked ~220 h. After 1-year a significant decrease (P < 0.0001) of systolic pressure was observed in both groups. The decrease was significantly higher (P < 0.0001) in the subjects under therapy. The decrease of systolic pressure was directly proportional to baseline values. Diastolic blood pressure decreased significantly in both groups. In conclusion, habitual walking may lead to clinically significant reductions of blood pressure in therapy resistant hypertensive subjects.

Prognostic comparison of the FRIEND and Wasserman/Hansen peak VO2 equations applied to a submaximal walking test in outpatients with cardiovascular disease

AIMS

The aim of this study was to determine the ability to predict all-cause mortality using established per cent-predicted (%PRED) equations for peak oxygen consumption (VO2peak) estimated by a submaximal walk test in outpatients with cardiovascular disease.

METHODS

Male patients (N = 1491) aged 62 ± 10 years at baseline underwent a moderate and perceptually regulated (11-13 on the 6-20 Borg scale) 1-km treadmill-walking test to estimate VO2peak. %PRED was derived from the Fitness Registry and the Importance of Exercise: A National Data Base (FRIEND) and the Wasserman/Hansen equations.

RESULTS

There were 215 deaths during a median 9.4-year follow-up. The FRIEND prediction equation provided better prognostic information with receiver operating curve analysis showing significantly different areas under the curve (0.72 and 0.69 for the FRIEND and the Wasserman/Hansen equations respectively, p = 0.001). Overall mortality rate was higher across decreasing tertiles of %PRED using FRIEND, with 26%, 11% and 5% for the least fit, intermediate and high fit tertiles, respectively (p for trend < 0.0001). Compared with the least fit tertile, the adjusted hazard ratios for the second and third tertiles were 0.54 (95% confidence interval 0.34-0.87, p = 0.01) and 0.45 (95% confidence interval 0.25-0.81, p = 0.008), respectively. Each 1% increase in %PRED conferred a 3% improvement in survival (p = 0.0004).

CONCLUSION

Low %PRED VO2peak in cardiac outpatients determined by the FRIEND equation was associated with a high mortality rate independent of traditional cardiovascular risk factors and clinical history. The FRIEND equation may provide a suitable normal standard when applied to clinically stable outpatients with cardiovascular disease.

Physical activity intervention for elderly patients with reduced physical performance after acute coronary syndrome (HULK study): rationale and design of a randomized clinical trial

Background

Reduced physical performance and impaired mobility are common in elderly patients after acute coronary syndrome (ACS) and they represent independent risk factors for disability, morbidity, hospital readmission and mortality. Regular physical exercise represents a means for improving functional capacity. Nevertheless, its clinical benefit has been less investigated in elderly patients in the early phase after ACS. The HULK trial aims to investigate the clinical benefit of an early, tailored low-cost physical activity intervention in comparison to standard of care in elderly ACS patients with reduced physical performance.

Design

HULK is an investigator-initiated, prospective multicenter randomized controlled trial (NCT03021044). After successful management of the ACS acute phase and uneventful first 1 month, elderly (≥70 years) patients showing reduced physical performance are randomized (1:1 ratio) to either standard of care or physical activity intervention. Reduced physical performance is defined as a short physical performance battery (SPPB) score of 4–9. The early, tailored, low-cost physical intervention includes 4 sessions of physical activity with a supervisor and an home-based program of physical exercise. The chosen primary endpoint is the 6-month SPPB value. Secondary endpoints briefly include quality of life, on-treatment platelet reactivity, some laboratory data and clinical adverse events. To demonstrate an increase of at least one SPPB point in the experimental arm, a sample size of 226 patients is needed.

Conclusions

The HULK study will test the hypothesis that an early, tailored low-cost physical activity intervention improves physical performance, quality of life, frailty status and outcome in elderly ACS patients with reduced physical performance.

Trial registration

Clinicaltrials.gov, identifier NCT03021044, first posted January, 13th 2017.

Electronic supplementary material

The online version of this article (10.1186/s12872-018-0839-8) contains supplementary material, which is available to authorized users.

Outdoor Reproducibility of a 1-km Treadmill Walking Test to Predict Peak Oxygen Uptake in Cardiac Patients

INTRODUCTION

The aim of this study was to determine whether the 1-km treadmill walking test, previously developed to predict peak oxygen uptake ((Equation is included in full-text article.)O2peak) in stable cardiac outpatients, could be reproduced outdoors.

METHODS

Fifty male cardiac outpatients performed the 1-km walking test on a treadmill and on a flat track within 1 week. (Equation is included in full-text article.)O2peak was estimated for both testing conditions considering age, height, weight, walking speed, and heart rate.

RESULTS

Average walking speed was slightly higher during outdoor conditions (5.73 ± 0.77 km/h vs 5.55 ± 0.84 km/h), whereas mean heart rates were similar for both testing conditions (102 ± 18 beats/min vs 103 ± 16 beats/min). (Equation is included in full-text article.)O2peak values for treadmill and outdoor tests were not significantly different (26.4 ± 4.1 mL/kg/min vs 26.8 ± 4.5 mL/kg/min) and were strongly correlated (r = 0.93, P < .0001). The slope and the intercept of the (Equation is included in full-text article.)O2peak values were not different from the line of identity.

CONCLUSIONS

This moderate and perceptually regulated 1-km walking test administered outdoors gives similar results compared with a similar test performed on a treadmill. Therefore, (Equation is included in full-text article.)O2peak can be reasonably estimated using both testing modalities. This suggests that the outdoor 1-km test can be applied for indirect estimations of cardiorespiratory fitness in an outpatient setting.

A moderate 500-m treadmill walk for estimating peak oxygen uptake in men with NYHA class I-II heart failure and reduced left ventricular ejection fraction

Background

Maximal cardiopulmonary exercise testing (CPX) is the gold-standard for cardiorespiratory fitness assessment in chronic heart failure (CHF) patients. However, high costs, required medical supervision, and safety concerns make maximal exercise testing impractical for evaluating mobility-impaired adults. Thus, several submaximal walking protocols have been developed and currently used to estimate peak oxygen consumption (VO₂peak) in CHF patients. However, these tests have to be performed at close to maximum exercise intensity. The aim of this study was to examine the validity of a 500-m treadmill-walking test carried out at moderate intensity for estimating VO₂peak in community-dwelling adult and elderly patients with CHF and reduced left ventricular ejection fraction (HFrEF).

Methods

Forty-three clinically stable men with HFrEF (age 67.7 ± 9.2 years, and left ventricular ejection fraction, LVEF 38% ± 6%) underwent exercise testing during an outpatient cardiac rehabilitation/secondary prevention program. Each patients completed a CPX, and a moderate and self-paced (11–13/20 on the Borg scale) 500-m treadmill-walking test. Age, weight, height, walk time, and heart rate during the 500-m test were entered into prediction equations previously validated for VO₂peak estimation from a 1000-m walking test in patients with cardiovascular disease and preserved LVEF.

Results

Directly measured and estimated VO₂peak values were not different (21.6 ± 4.9 vs 21.7 ± 4.6 mL/kg/min). The comparison between measured and estimated VO₂peak values yielded a correlation of R = 0.97 (SEE = 0.7 mL/kg/min, P < 0.0001). The slope and the intercept coincided with the line of identity (Passing and Bablock analysis, P = 0.50). Residuals were normally distributed, and the examination of the Bland-Altman analysis do not show systematic or proportional error.

Conclusions

A moderate and self-regulated 500-m treadmill-walking test is a valid tool for VO₂peak estimation in patients with HFrEF. These findings may have practical implications in the context of transitioning from clinically based programs to fitness facilities or self-guided exercise programs in adults and elderly men with HFrEF.

Electronic supplementary material

The online version of this article (10.1186/s12872-018-0801-9) contains supplementary material, which is available to authorized users.

A study on nonlinear estimation of submaximal effort tolerance based on the generalized MET concept and the 6MWT in pulmonary rehabilitation

BACKGROUND

The six-minute walk test (6MWT) is considered to be a simple and inexpensive tool for the assessment of functional tolerance of submaximal effort. The aim of this work was 1) to background the nonlinear nature of the energy expenditure process due to physical activity, 2) to compare the results/scores of the submaximal treadmill exercise test and those of 6MWT in pulmonary patients and 3) to develop nonlinear mathematical models relating the two.

METHODS

The study group included patients with the COPD. All patients were subjected to a submaximal exercise test and a 6MWT. To develop an optimal mathematical solution and compare the results of the exercise test and the 6MWT, the least squares and genetic algorithms were employed to estimate parameters of polynomial expansion and piecewise linear models.

RESULTS

Mathematical analysis enabled to construct nonlinear models for estimating the MET result of submaximal exercise test based on average walk velocity (or distance) in the 6MWT.

CONCLUSIONS

Submaximal effort tolerance in COPD patients can be effectively estimated from new, rehabilitation-oriented, nonlinear models based on the generalized MET concept and the 6MWT.

Stroke Prevention Rehabilitation Intervention Trial of Exercise (SPRITE) - a randomised feasibility study

BACKGROUND

The value of cardiac rehabilitation (CR) after a transient ischaemic attack (TIA) or minor stroke is untested despite these conditions sharing similar pathology and risk factors to coronary heart disease. We aimed to evaluate the feasibility of conducting a trial of an adapted home-based CR programme, 'The Healthy Brain Rehabilitation Manual', for patients following a TIA/minor stroke, participants' views on the intervention and, to identify the behaviour change techniques (BCTs) used.

METHODS

Clinicians were asked to identify patients attending the Ulster Hospital, Belfast within 4 weeks of a first TIA or minor stroke. Those who agreed to participate underwent assessments of physical fitness, cardiovascular risk, quality of life and mental health, before random allocation to: Group (1) standard/usual care; (2) rehabilitation manual or (3) manual plus pedometer. All participants received telephone support at 1 and 4 weeks, reassessment at 6 weeks and an invitation to a focus group exploring views regarding the study. Two trained review authors independently assessed the manual to identify the BCTs used.

RESULTS

Twenty-eight patients were invited to participate, with 15 (10 men, 5 women; 9 TIA, 6 minor stroke; mean age 69 years) consenting and completing the study. Mean time to enrolment from the TIA/stroke was 20.5 days. Participants completed all assessment measures except VO2max testing, which all declined. The manual and telephone contact were viewed positively, as credible sources of advice. Pedometers were valued highly, particularly for goal-setting. Overall, 36 individual BCTs were used, the commonest being centred around setting goals and planning as well as social support.

CONCLUSION

Recruitment and retention rates suggest that a trial to evaluate the effectiveness of a novel home-based CR programme, implemented within 4 weeks of a first TIA/minor stroke is feasible. The commonest BCTs used within the manual revolve around goals, planning and social support, in keeping with UK national guidelines. The findings from this feasibility work have been used to further refine the next stage of the intervention's development, a pilot study.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02712385 . This study was registered prospectively on 18/03/2016.

Heart rate recovery of individuals undergoing cardiac rehabilitation after acute coronary syndrome

BACKGROUND

An efficient cardiac rehabilitation programme (CRP) can improve the functional ability of patients after acute coronary syndrome (ACS).

OBJECTIVE

To examine the effect of a CRP on parasympathetic reactivation and heart rate recovery (HRR) measured after a 6-min walk test (6MWT), and correlation with 6MWT distance and well-being after ACS.

METHODS

Eleven normoweight patients after ACS (BMI<25kg/m²; 10 males; mean [SD] age 61 [9] years) underwent an 8-week CRP. Before (pre-) and at weeks 4 (W4) and 8 (W8) during the CRP, they performed a 6MWT on a treadmill, followed by 10-min of seated passive recovery, with HRR and HR variability (HRV) recordings. HRR was measured at 1, 3, 5 and 10min after the 6MWT (HRR1, HRR3, HRR5, HRR10), then modelized by a mono-exponential function. Time-domain (square root of the mean of the sum of the squares of differences between adjacent normal R-R intervals [RMSSD]) and frequency-domain (with high- and low-frequency band powers) were used to analyse HRV. Participants completed a mental and physical well-being questionnaire at pre- and W8. Exhaustion after tests was assessed by the Borg scale. Pearson correlation was used to assess correlations.

RESULTS

HRR3, HRR5 and HRR10 increased by 37%, 36% and 28%, respectively, between pre- and W8 (P<0.05), and were positively correlated with change in 6MWT distance (r=0.58, 0.66 and 0.76; P<0.05). Percentage change in HRR3 was positively correlated with change in well-being (r=0.70; P=0.01). Parasympathic reactivation (RMSSD) was improved only during the first 30sec of recovery (P=0.04).

CONCLUSION

Among patients undergoing a CRP after ACS, increased HRR after a 6MWT, especially at 3min, was positively correlated with 6MWT distance and improved well-being. HRR raw data seem more sensitive than post-exercise HRV analysis for monitoring functional and autonomic improvement after ACS.

Improved walking speed is associated with lower hospitalisation rates in patients in an exercise-based secondary prevention programme

OBJECTIVE

To determine the relationship between walking speed (WS) maintained during a 1 km test and its improvement on hospitalisation in cardiac outpatients who were referred to an exercise-based secondary prevention programme.

METHODS

Hospitalisation was assessed in 1791 patients 3 years after enrolment and related to the WS achieved during a 1 km walk at moderate intensity on a treadmill. Hospitalisation was also assessed during the fourth-to-sixth years as function of improvement in WS in 1111 participants who were re-evaluated 3 years after baseline.

RESULTS

Three-year hospitalisation rate across tertiles of baseline WS was 50% for the slow walkers (2.7±0.6 km/hour), 41% for the moderate (4.1±0.3 km/hour) and 25% for the fast walkers (5.2±0.5 km/hour) (p for trend <0.0001), with adjusted HRs (95% CI) of 0.93 (0.74 to 1.17, p=0.53) for intermediate and 0.58 (0.43 to 0.78, p=0.0003) for fast. Every 1 km/hour increase in WS was associated with a 21% reduction in hospitalisation (p<0.0001). Hospitalisation from the fourth-to-sixth years was lower across tertiles of improved WS, with 44% for the low (0.2±0.4 km/hour), 34% for the intermediate (0.8±0.2 km/hour) and 30% for the high tertile (1.6±0.4 km/hour) (p for trend <0.0001). Adjusted HRs were 0.68 (p=0.002) for the intermediate and 0.58 (p<0.0001) for the high tertile. Every 1 km/hour increase in WS was associated with a 35% reduction in hospitalisation (p<0.0001).

CONCLUSION

Improvement in WS is associated with a significant, dose-dependent lower rate of all-cause hospitalisation in cardiac outpatients. WS is a simple, easily applied and clinically useful tool for cardiac patients undergoing secondary prevention.

Association between VO₂ peak estimated by a 1-km treadmill walk and mortality. A 10-year follow-up study in patients with cardiovascular disease

PURPOSE

The aim of this study is to assess the association between peak oxygen uptake (VO2 peak), determined using a perceptually regulated 1-km walking test (1k-TWT), and all-cause mortality in cardiac patients.

METHODS

1255 male patients, aged 25-85 years, completed a moderate 1k-TWT to estimate VO2 peak. Subjects were followed for all-cause mortality for up to 10 years. Cox proportional hazard models were employed to determine variables associated with mortality. Based on the estimated VO2 peak, the sample was subdivided into quartiles and mortality risks were calculated. To assess the discriminatory accuracy of the estimated VO2 peak for estimating survival, receiver-operating-characteristics curves were constructed.

RESULTS

During a median 8.2 year follow-up, a total of 141 deaths from any cause occurred, yielding an average annual mortality of 1.4%. The strongest predictor of all-cause mortality was the estimated VO2 peak (c-statistic 0.71, 95% confidence intervals: 0.69-0.74, P<0.0001). Survival decreased in a graded fashion from the highest estimated VO2 peak quartile to the lowest quartile. Compared to the lowest quartile, the hazard ratios (95% confidence intervals) for the second, third, and fourth quartiles were 0.77 (0.35-1.33), 0.43 (0.20-0.91), and 0.16 (0.05-0.54) respectively (P for trend <0.0001). An 89% reduction in mortality risk was observed among a subset of subjects in the fittest quartile who improved their estimated VO2 peak over the follow-up period relative to subjects in the least fit quartile who did not improve.

CONCLUSION

VO2 peak estimated by a novel 1k-TWT predicts survival in subjects with stable cardiovascular disease.

Treadmill walking speed and survival prediction in men with cardiovascular disease: a 10-year follow-up study

OBJECTIVE

To determine whether the walking speed maintained during a 1 km treadmill test at moderate intensity predicts survival in patients with cardiovascular disease.

DESIGN

Population-based prospective study.

SETTING

Outpatient secondary prevention programme in Ferrara, Italy.

PARTICIPANTS

1255 male stable cardiac patients, aged 25-85 years at baseline.

MAIN OUTCOME MEASURES

Walking speed maintained during a 1 km treadmill test, measured at baseline and mortality over a median follow-up of 8.2 years.

RESULTS

Among 1255 patients, 141 died, for an average annual mortality of 1.4%. Of the variables considered, the strongest predictor of all-cause mortality was walking speed (95% CI 0.45 to 0.75, p<0.0001). Based on the average speed maintained during the test, participants were subdivided into quartiles and mortality risk adjusted for confounders was calculated. Compared to the slowest quartile (average walking speed 3.4 km/h), the relative mortality risk decreased for the second, third and fourth quartiles (average walking speed 5.5 km/h), with HRs of 0.73 (95% CI 0.46 to 1.18); 0.54 (95% CI 0.31 to 0.95) and 0.20 (95% CI 0.07 to 0.56), respectively (p for trend <0.0001). Receiver operating curve analysis showed an area under the curve of 0.71 (p<0.0001) and the highest Youden index (0.35) for a walking speed of 4.0 km/h.

CONCLUSIONS

The average speed maintained during a 1 km treadmill walking test is inversely related to survival in patients with cardiovascular disease and is a simple and useful tool for stratifying risk in patients undergoing secondary prevention and cardiac rehabilitation programmes.