Treadmill validation of an over-ground walking test to predict peak oxygen consumption

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.

Exercise as a smoking cessation treatment for women: a randomized controlled trial

Cigarette smoking remains the leading behavioral risk factor for chronic disease and premature mortality. This RCT tested the efficacy of moderate intensity aerobic exercise as an adjunctive smoking cessation treatment among women. Participants (N = 105; age = 42.5, SD = 11.2) received brief smoking cessation counseling and 10 weeks of nicotine replacement therapy and were randomized to 12 weeks of moderate intensity exercise (Exercise; n = 53) or 12 weeks of health education (Control; n = 52). Longitudinal models, with Generalized Estimating Equations, showed no differences between Exercise and Control in cotinine-verified 7-day point prevalence abstinence (Wald = 1.96, p = 0.10) or continuous abstinence (Wald = 1.45, p = 0.23) at 12-weeks (post-treatment) or 6-, 9-, or 12-month follow-up, controlling for differences in baseline nicotine dependence. There was no effect of exercise on smoking cessation. The present study adds to the literature suggesting null effects of exercise as a smoking cessation adjunctive treatment despite promising findings in short-term laboratory based studies.

A validation study of the use of smartphones and wrist-worn ActiGraphs to measure physical activity at different levels of intensity and step rates in older people

BACKGROUND

Physical activity promotes healthy ageing in older people. Accurate measurement of physical activity in free-living environment is important in evaluating physical activity interventions.

RESEARCH QUESTION

What is the criterion validity of 1)an ActiGraph to identify physical activity at different intensity levels and 2)an ActiGraph and a smartphone to measure step rate?

METHODS

Community-dwelling older people aged≥60 were recruited. The index tests were using ActiGraph worn in different positions (i.e.,both wrists and hip) to measure physical activity intensity and step rate and using smartphone (i.e., Samsung J2 pro and Google Fit) worn in different positions (i.e.,trousers pocket and waist pouch) to measure the step rate. The reference standards were using indirect calorimetry (i.e.,CosMedK4b 2) to measure physical activity intensity and using direct observation for step rate. Subjects were exposed in different physical activity intensity levels (i.e.,sedentary:MET < 1.5,light: MET = 1.5-2.99, moderate:MET = 3.0-6.0, vigorous:MET>6) and step rates through walking on a treadmill at different speeds (i.e.,2-8 km) for approximately 30 min. Spearman's rho, ROC analysis, and percentage error were employed to report the criterion validity.

RESULTS

31 participants completed the tests. ActiGraphs worn in different body positions could significantly differentiate physical activity intensity at the levels of "light- or-above" (VM cut-off = 279.5-1959.1,AUC = 0.932-0.954), "moderate-or-above" (VM cut- off = 1051.0-4212.9,AUC = 0.918-0.932), and "vigorous" (VM cut-off = 3335.4-5093.0, AUC = 0.890-0.907) well with different cut-off points identified. The step rate measured by direct observation correlated significantly with ActiGraph and smartphone (rho = 0.415-0.791). Both ActiGraph and smartphone at different positions generally underestimated the step rate (%error= -20.5,-30.3).

SIGNIFICANCE

A wrist-worn ActiGraph can accurately identify different physical activity intensity levels in older people, but lower cut-off points in older people should be adopted. To measure step rate, a hip-mounted ActiGraph is preferable than a wrist- worn one. A smartphone employing Google Fit generally underestimates step rate but it gives a relatively more accurate estimation of step rate when the older people walk at a speed of 4-8 km/h.

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.

Association of Body Esteem with Fitness and Body Fat Among Colorectal Cancer Survivors: Secondary Analyses from a Randomized Trial

BACKGROUND

Survival rates among cancer survivors have improved; however, treatments affect body esteem. Body esteem can significantly affect quality of life and depression following cancer treatment. The purpose of these secondary analyses was to examine the relationship between changes in fitness and body fat with changes in body esteem among colorectal cancer survivors who participated in a randomized controlled trial that tested the effects of a 12-week physical activity intervention.

METHOD

Male and female colorectal cancer survivors (< 5 years since diagnosis) participated in a randomized controlled trial that tested a 12-week moderate-intensity physical activity intervention. Body esteem, fitness (estimated VO₂ peak), and body composition (bioelectrical impedance) were assessed at baseline and follow-up visits (3 months, 6 months, and 12 months).

RESULTS

Forty-six colorectal cancer survivors (57 years old, 57% female) completed the study. Improvements in fitness were associated with improvements in body esteem among males at 6-month and 12-month follow-up visits, while improvements in body fat were associated with increased body esteem at 12-month follow-up among females. Improvements in fitness and body fat among stage 0-2 survivors were associated with significant improvements in body esteem, with no significant changes among stage 3 survivors.

CONCLUSION

Results from this study showed that improved fitness and body composition can improve body esteem among these survivors; however, differences exist among gender and disease stage.

TRIAL REGISTRATION

https://clinicaltrials.gov/ct2/show/NCT00230646?term=Pinto&cond=Colorectal+Cancer&rank=2.

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.

Heart rate variability and plasma biomarkers in patients with type 1 diabetes mellitus: Effect of a bout of aerobic exercise

OBJECTIVE

The aim of this study was to evaluate: (1) the cardiovascular parameters and plasma biomarkers in people with type 1 diabetes mellitus (T1DM) at baseline; and (2) the heart rate variability (HRV) and blood glucose in response to a session of aerobic exercise (AE) and during recovery period.

RESEARCH DESIGN AND METHODS

Adults (18-35 years) were divided into two groups: control (CT, n=10) and T1DM (n=9). Anthropometric, cardiovascular, and biochemical parameters, and aerobic capacity (indirect peak oxygen uptake, VO2peak) were evaluated at baseline. Thirty minutes of AE (40-60% intensity) was performed on a treadmill. Blood glucose and HRV were determined at rest, during AE, and during the recovery period.

RESULTS

Anthropometric measurements, cardiovascular parameters, aerobic capacity, and biochemical parameters were similar between the groups at baseline. In the T1DM group, blood glucose, glycated hemoglobin, and thiobarbituric acid reactive substances concentrations were increased while nitrite/nitrate (NOx(-)) levels were reduced. During AE, the magnitude of the reduction of blood glucose was greater than that during the recovery period in the T1DM group. The RR intervals and SDNN were reduced at rest as well as in the recovery period in T1DM subjects, whereas the RMSSD and pNN50 were only reduced during the recovery period. No changes were observed in low frequency (LF), high frequency (HF), and LF/HF ratio.

CONCLUSION

Our study shows that T1DM patients on insulin therapy have poor blood glucose control with greater lipid peroxidation and lower NOx(-) levels, accompanied by an imbalance in autonomic function detected by the challenge of AE.

Recommending self-paced exercise among overweight and obese adults: a randomized pilot study

BACKGROUND

National guidelines call for exercise of at least moderate intensity; however, recommending self-paced exercise may lead to better adherence, particularly among overweight and obese adults.

PURPOSE

The purpose of this study was to test proof-of-concept for recommending self-paced exercise among overweight adults.

METHODS

Fifty-nine healthy, low-active (exercise <60 min/week), overweight (body mass index 25.0-39.9) adults (18-65) received a 6-month print-based exercise promotion program with the goal of walking 30-60 min/day. Participants were surreptitiously randomly assigned to receive a recommendation for either self-paced (n = 30) or moderate (64-76 % maximum heart rate; n = 29) intensity exercise. All participants used electronic diaries and heart rate monitors to track exercise frequency, duration, and intensity.

RESULTS

The self-paced condition reported more minutes/week of walking (f (2) = 0.17, p = 0.045) and a trend toward greater exercise-related energy expenditure/week (f (2) = 0.12, p = 0.243), corresponding to approximately 26 additional minutes/week and 83 additional kilocalories/week over 6 months.

CONCLUSIONS

Explicit recommendation for self-paced exercise may improve adherence to exercise programs among overweight and obese adults.

The presence of the NOS3 gene polymorphism for intron 4 mitigates the beneficial effects of exercise training on ambulatory blood pressure monitoring in adults

The number of studies that have evaluated exercise training (ET) and nitric oxide synthase (NOS)3 gene polymorphisms is scarce. The present study was designed to evaluate the relationship between exercise training and NOS3 polymorphisms at -786T>C, 894G>T, and intron 4b/a on blood pressure (BP) using 24-h ambulatory BP monitoring (ABPM), nitrate/nitrite levels (NOx), and redox state. Eighty-six volunteers (51 ± 0.6 yr old) were genotyped into nonpolymorphic and polymorphic groups for each of the three positions of NOS3 polymorphisms. Auscultatory BP, ABPM, SOD activity, catalase activity, NOx levels, and malondialdehyde levels were measured. DNA was extracted from leukocytes, and PCR followed by sequencing was applied for genotype analysis. Aerobic ET consisted of 24 sessions for 3 days/wk for 40 min at moderate intensity. This study was performed in a double-blind and crossover format. ET was effective in lowering office BP (systolic BP: 3.2% and diastolic BP: 3%) as well as ABPM (systolic BP: 2% and diastolic BP: 1.3%). Increased SOD and catalase activity (42.6% and 15.1%, respectively) were also observed. The NOS3 polymorphism for intron 4 mitigated the beneficial effect of ET for systolic BP (nonpolymorphic group: -3.0% and polymorphic group: -0.6%) and diastolic BP (nonpolymorphic group: -3.2% and polymorphic group: -0.5%), but it was not associated with NOx level and redox state. Paradoxical responses were found for positions T786-C and G894T for the NOS3 gene. Consistently, the presence of the polymorphism for intron 4 blunted the beneficial effects of ET in middle-aged adults. Possibly, this effect might be as consequence of intron 4 acting as a short intronic repeat RNA controlling endothelial NOS activity epigenetically.

Overcoming limitations in previous research on exercise as a smoking cessation treatment: rationale and design of the "Quit for Health" trial

Aerobic exercise has been proposed as a stand-alone or adjunct smoking cessation treatment, but findings have been mixed. Laboratory studies have shown that individual exercise sessions lead to decreases in withdrawal symptoms and cigarette cravings, but findings are limited by lack of follow-up and artificial settings. On the other hand, smoking cessation treatment RCTs have generally failed to show positive effects of exercise on smoking cessation, but have been plagued by poor and/or unverified compliance with exercise programs. This paper describes the rationale and design for Quit for Health (QFH)--an RCT designed to determine the efficacy of aerobic exercise as an adjunct smoking cessation treatment among women. To overcome limitations of previous research, compliance with the exercise (and wellness contact control) program is incentivized and directly observed, and ecological momentary assessment is used to examine change over time in withdrawal symptoms and cigarette cravings in participants' natural environments.

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

PURPOSE

To determine whether a moderate 1-km treadmill walking test (1KTWT) could be used to predict peak oxygen uptake VO(2)peak) in patients with cardiovascular disease.

METHODS

One hundred seventy-eight male patients, aged 38 to 83 years, completed a VO(2)peak treadmill test and a 1KTWT using a self-regulated intensity of 11 to 13 of 20 on the Borg scale. Multivariable regression analysis was used to develop equations for predicting VO(2)peak in a development group (n = 110), both for subjects prescribed and not prescribed a β-blocking agent (BB/NBB, 66/44). These equations were then applied to a cross-validation and reproducibility group (n = 68, BB/NBB, 37/31), who completed the protocol twice within 2 weeks.

RESULTS

Analysis from 1KTWT in the development group showed that age, body mass index, walking speed, and heart rate were the most potent predictors of VO(2)peak. Measured and predicted VO(2)peak were not significantly different, and were strongly associated among both the NBB (r = 0.81, P < .0001) and BB (r = 0.69, P < .0001) groups, with a mean residual of approximately 1.0 mL·kg(-1)·min(-1). When applied to the cross-validation and reproducibility group, the equations similarly yielded strong associations (r = 0.64, P < 0.001 and r = 0.71, P < 0.001 for the NBB and BB groups, respectively), with no significantly differences between measured and predicted VO(2)peak. Mean test-retest differences for measured and predicted VO(2)peak were between 0.1 and -0.5 mL·kg(-1)·min(-1).

CONCLUSIONS

Equations developed from the 1KTWT accurately predicted VO(2)peak in patients with cardiovascular disease. The model may represent a valid, low cost, and simple tool for indirect estimations of cardiorespiratory fitness in an outpatient setting.

Home-based physical activity intervention for colorectal cancer survivors

BACKGROUND

The efficacy of a home-based physical activity (PA) intervention for colorectal cancer patients versus contact control was evaluated in a randomized controlled trial.

METHODS

Forty-six patients (mean age = 57.3 years [SD = 9.7], 57% female, mean = 2.99 years post-diagnosis [SD = 1.64]) who had completed treatment for stages 1-3 colorectal cancer were randomized to telephone counseling to support PA (PA group, n = 20) or contact control (control group, n = 26). PA group participants received 3 months of PA counseling (based on the transtheoretical model and the social cognitive theory) delivered via telephone, as well as weekly PA tip sheets. Assessments of PA (Seven-day Physical Activity Recall [7-day PAR] and Community Healthy Activities Model Program for Seniors [CHAMPS]), submaximal aerobic fitness (Treadwalk test), motivational readiness for PA, and psychosocial outcomes were conducted at baseline, 3, 6, and 12 months post-baseline. Objective accelerometer data were collected at the same time points.

RESULTS

The PA group reported significant increases in minutes of PA at 3 months (7-day PAR) and caloric expenditure (CHAMPS) compared with the control group, but the group differences were attenuated over time. The PA group showed significant improvements in fitness at 3, 6, and 12 months versus the control group. Improvements in motivational readiness for PA were reported in the PA group only at 3 months. No significant group differences were found for fatigue, self-reported physical functioning, and quality of life at 3, 6, and 12 months.

CONCLUSION

A home-based intervention improved survivors' PA and motivational readiness at 3 months and increased submaximal aerobic fitness at 3, 6, and 12 months.

Pulmonary diffusion and aerobic capacity: is there a relation? Does obesity matter?

AIM

We sought to determine whether pulmonary diffusing capacity for nitric oxide (DLNO), carbon monoxide (DLCO) and pulmonary capillary blood volume (Vc) at rest predict peak aerobic capacity (VO2peak), and if so, to discern which measure predicts better.

METHODS

Thirty-five individuals with extreme obesity (body mass index or BMI = 50 +/- 8 kg m((-2)) and 26 fit, non-obese subjects (BMI = 23 +/- 2 kg m((-2)) participated. DLNO and DLCO at rest were first measured. Then, subjects performed a graded exercise test on a cycle ergometer to determine (VO2peak). Multivariate regression was used to assess relations in the data.

RESULTS

Findings indicate that (i) pulmonary diffusion at rest predicts (VO2peak) in the fit and obese when measured with DLNO, but only in the fit when measured with DLCO; (ii) the observed relation between pulmonary diffusion at rest and (VO2peak) is different in the fit and obese; (iii) DLNO explains (VO2peak) better than DLCO or Vc. The findings imply the following reference equations for DLNO: (VO2peak) (mL kg(-1) min(-1)) = 6.81 + 0.27 x DLNO for fit individuals; (VO2peak) (mL kg(-1) min(-1)) = 6.81 + 0.06 x DLNO, for obese individuals (in both groups, adjusted R(2 )=( )0.92; RMSE = 5.58).

CONCLUSION

Pulmonary diffusion at rest predicts (VO2peak), although a relation exists for obese subjects only when DLNO is used, and the magnitude of the relation depends on gender when either DLCO or Vc is used. We recommend DLNO as a measure of pulmonary diffusion, both for its ease of collection as well as its tighter relation with (VO2peak).

Development and validation of a one-mile treadmill walk test to predict peak oxygen uptake in healthy adults ages 40 to 79 years

The purpose of this investigation was to determine whether the Rockport one-mile walk test equation to predict maximal oxygen uptake was valid for application to treadmill walking. When the Rockport model was found to be inappropriate, a new regression model was developed for predicting peak oxygen uptake (VO2peak) from a one-mile treadmill walk. 304 healthy volunteers ages 40 to 79 years (mean age = 57.6 years, 154 men and 150 women) completed a VO2peak test and a one-mile treadmill walk. Stepwise regression was used to build a model for the relationship between VO2peak and a variety of predictor variables in a sub-sample development group (n = 154). This new model was then applied to a sub-sample validation group (n = 150). The new equation produced a correlation of 0.87, SEE = 4.7 ml x kg (-1) x min (-1) with a mean residual of 0.96 ml x kg (-1) x min (-1). The equation for predicting VO2peak developed in this investigation provides a means of assessing VO2peak that is easy to administer, allows for careful supervision of subjects, and can be completed at a low financial and temporal cost.