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.

Supervised exercise training improves endothelial function in COPD patients: a method to reduce cardiovascular risk?

Supervised exercise training is key to health improvement in chronic obstructive pulmonary disease patients https://bit.ly/2AdfKvb.

Indoor air pollution exposure effects on lung and cardiovascular health in the High Himalayas, Nepal: An observational study.

BACKGROUND: Exposure to indoor biomass fuel smoke is associated with increased morbidity and mortality. The aim of this study is to evaluate the association between exposure to indoor biomass burning and early pulmonary and cardiovascular damage. METHODS: The indoor levels of particulate matter (PM) [PM10, PM2.5] and black carbon (BC) were monitored in 32 houses in a Himalayan village. Seventy-eight subjects were submitted to spirometry and cardiovascular evaluation [carotid to femoral pulse wave velocity (PWV) and echocardiography]. RESULTS: Peak indoor BC concentration up to 100 µg m-3 and PM10 - PM2.5 up to 1945-592 µg m-3 were measured. We found a non-reversible bronchial obstruction in 18% of subjects ≥40 yr; mean forced expiratory flow between 25% and 75% of the forced vital capacity (FEF25-75) <80% in 54% of subjects, suggestive of early respiratory impairment, significantly and inversely related to age. Average BC was correlated with right ventricular-right atrium gradient (R = 0.449,p = .002), total peripheral resistances (TPR) (R = 0.313,p = .029) and PWV (R = 0.589,p < .0001) especially in subjects >30 yr. In multiple variable analysis, BC remained an independent predictor of PWV (ß = 0.556,p = .001), and TPR (ß = 0.366;p = .018). CONCLUSIONS: Indoor pollution exposure is associated to early pulmonary and cardiovascular damages, more evident for longer duration and higher intensity exposure.

Endothelial Function in COPD Is in an Intermediate Position Between Healthy Subjects and Coronary Artery Disease Patients and Is Related to Physical Activity.

Patients with chronic obstructive pulmonary disease (COPD) have an increased risk of ischemic heart disease. Endothelial dysfunction may play a role in the onset of cardiovascular event. Previous studies showed an impaired endothelial function (measured by flow-mediated dilation, FMD) in COPD patients compared to healthy subjects. To the best of our knowledge no study has compared FMD in COPD and in cardiac (coronary artery disease, CAD) patients. We aimed to assess FMD in healthy subjects, COPD, CAD, and COPD + CAD. The main result is that FMD in COPD is reduced and is in an intermediate position between healthy subjects and CAD or COPD + CAD; this impairment can contribute to explain the higher prevalence of cardiovascular disease in COPD. The only determinant independently associated with FMD in all subjects is the physical activity level, irrespective of the traditional risk factors (i.e., smoke, dyslipidemia, hypertension).

Home-Based, Moderate-Intensity Exercise Training Using a Metronome Improves the Breathing Pattern and Oxygen Saturation During Exercise in Patients With COPD.

PURPOSE: One of the well-known but less-investigated effects of pulmonary rehabilitation in patients with chronic obstructive pulmonary disease (COPD) is the change in breathing pattern toward a more efficient one (higher tidal volume [VT], lower breathing frequency). Evidence suggests this change can be obtained only with supervised, high-intensity exercise training (ExTr). However, some patients either do not have such programs available or are unable to exercise at higher intensity. We evaluated the effects of a 12-wk, moderate-intensity, home-monitored ExTr program using a metronome on the breathing pattern, oxygen saturation (SpO2), and dyspnea during exercise in patients with COPD. METHODS: Twenty-one patients with COPD (7 female, aged 64-85 yr) performed spirometry, incremental, and endurance walking tests (at 60% of maximal walking speed) on a treadmill before and after training. During the endurance test, patients were equipped with an instrument that continuously monitored ventilation ((Equation is included in full-text article.)E), breathing pattern, and SpO2. Patients trained at home for 12 wk, 30 min/d for at least 4 d/wk at moderate intensity. A metronome paced the walking speed. RESULTS: Sixteen patients completed the program. After training, a significant change was observed in breathing pattern (lower (Equation is included in full-text article.)E and (Equation is included in full-text article.)E/VT ratio; P < .001), a higher SpO2 (P < .001), and a lower dyspnea perception at the same work intensity (P < .01). The (Equation is included in full-text article.)E/VT ratio and SpO2 during exercise were significantly related (r = 0.56, P = .001). CONCLUSION: A change in breathing pattern towards more efficient ventilation can be obtained with a moderate, home-monitored ExTr program with a pace that is controlled by a metronome. Decreased (Equation is included in full-text article.)E/VT was associated with an improved SpO2 during exercise.

Relationship Between Occupational Physical Activity and Subclinical Vascular Damage in Moderate-Altitude Dwellers.

Ujka, Kristian, Rosa Maria Bruno, Luca Bastiani, Eva Bernardi, Paolo Sdringola, Nenad Dikic, Bikash Basyal, Sanjeeb Sundarshan Bhandari, Buddha Basnyat, Annalisa Cogo, and Lorenza Pratali. Relationship between occupational physical activity and subclinical vascular damage in moderate-altitude dwellers. High Alt Med Biol. 18:249-257, 2017. BACKGROUND: Occupational physical activity (OPA) has been associated with increased cardiovascular (CV) events. The aim of this study was to investigate the association between OPA and markers of subclinical vascular damage among a moderate-altitude population living in the rural village of Chaurikharka (Nepal; 2600 m sea level). METHODS: Seventy-two individuals (age 42 ± 15 years, ranges 15-85 years, 23 men) were enrolled. Physical activity (PA) was evaluated using the International Physical Activity Questionnaire (IPAQ). Carotid-femoral pulse wave velocity (PWV), carotid ultrasound assessment, and flow-mediated dilation (FMD) were performed. RESULTS: OPA was 9860 ± 5385 Metabolic Equivalent of Task (MET)-minutes/week, representing 77% of total energy expenditure, with 97% of the population performing high-intensity PA. In the univariate analysis, OPA was significantly associated with PWV (ß = 0.474, p = 0.001) and carotid stiffness (CS) (ß = 0.29, p = 0.019). In the multivariate analysis, including age, sex, oxygen saturation, mean blood pressure, low-density lipoprotein (LDL), and OPA, OPA remained an independent predictor of PWV (ß = 0.403, p = 0.001) but not of CS (ß = 0.028, p = 0.8). OPA remained an independent predictor of PWV independently from the Framingham risk score (FRS). CONCLUSION: High-intensity OPA shows a positive, independent association with aortic stiffness in Himalayan moderate-altitude dwellers. This study suggests how vigorous OPA performed in moderate altitude may be a CV risk factor.

Residence at Moderate Versus Low Altitude Is Effective at Maintaining Higher Oxygen Saturation During Exercise and Reducing Acute Mountain Sickness Following Fast Ascent to 4559 m.

OBJECTIVE: To continuously monitor oxygen saturation (SpO2) by pulse oximeter and assess the development of acute mountain sickness (AMS) using the Lake Louise Score (LLS) during ascent from 1154 to 4559 m in 2 groups of subjects: 10 moderate-altitude residents (MAR; ≥1000-≤2500 m) and 34 low-altitude residents (LAR). MAR are reported to have a lower incidence of AMS during ascent to higher altitudes compared with LAR. Whether this is related to higher SpO2 is still open to debate. METHODS: Seventy subjects were recruited; 24-hour SpO2 monitoring with finger pulse oximetry was performed. All subjects rode a cable car from 1154 to 3275 m and then climbed to 3647 m, where 60 subjects (LAR) overnighted. The second day, 34/60 LAR reached the highest altitude. Ten subjects who lived permanently at 1100 to 1400 m (MAR) climbed directly to 4559 m without an overnight stop. RESULTS: One LAR was excluded from the analysis because he performed a preacclimatization. We compared data of 10 MAR with data of 33 LAR who reached 4559 m. Two MAR had an LLS of 3, and 8 scored <3. Six LAR had an LLS of 3 to 4, 8 scored ≥5, and 19 scored <3. SpO2 monitoring showed higher mean SpO2 in MAR during ascent above 3600 m compared with LAR (MAR, 79±4% vs LAR, 76±5%; analysis of variance, P = .03). CONCLUSIONS: The results of this preliminary study suggest that residence at moderate altitude allows maintenance of higher SpO2 and reduces risk of developing AMS during rapid ascent to higher altitude.

Thoraco-abdominal coordination and performance during uphill running at altitude.

INTRODUCTION: Running races on mountain trails at moderate-high altitude with large elevation changes throughout has become increasingly popular. During exercise at altitude, ventilatory demands increase due to the combined effects of exercise and hypoxia. AIM: To investigate the relationships between thoraco-abdominal coordination, ventilatory pattern, oxygen saturation (SpO2), and endurance performance in runners during high-intensity uphill exercise. METHODS: Fifteen participants (13 males, mean age 42±9 yrs) ran a "Vertical Kilometer," i.e., an uphill run involving a climb of approximately 1000 m with a slope greater than 30%. The athletes were equipped with a portable respiratory inductive plethysmography system, a finger pulse oximeter and a global positioning unit (GPS). The ventilatory pattern (ventilation (VE), tidal volume (VT), respiratory rate (RR), and VE/VT ratio), thoraco-abdominal coordination, which is represented by the phase angle (PhA), and SpO2 were evaluated at rest and during the run. Before and after the run, we assessed respiratory function, respiratory muscle strength and the occurrence of interstitial pulmonary edema by thoracic ultrasound. RESULTS: Two subjects were excluded from the respiratory inductive plethysmography analysis due to motion artifacts. A quadratic relationship between the slope and the PhA was observed (r = 0.995, p = 0.036). When the slope increased above 30%, the PhA increased, indicating a reduction in thoraco-abdominal coordination. The reduced thoraco-abdominal coordination was significantly related to reduced breathing efficiency (i.e., an increased VE/VT ratio; r = 0.961, p = 0.038) and SpO2 (r = -0.697, p<0.001). Lower SpO2 values were associated with lower speeds at 20%≥slope≤40% (r = 0.335, p<0.001 for horizontal and r = 0.36, p<0.001 for vertical). The reduced thoraco-abdominal coordination and consequent reduction in SpO2 were associated with interstitial pulmonary edema. CONCLUSION: Reductions in thoraco-abdominal coordination are associated with a less efficient ventilatory pattern and lower SpO2 during uphill running. This fact could have a negative effect on performance.

Oxygen Uptake Attenuation at Ventilatory Threshold in Men With Coronary Artery Disease.

PURPOSE: Maximal oxygen uptake ((Equation is included in full-text article.)O2) and ventilatory threshold (VT) are widely used to assess cardiorespiratory fitness in healthy people, as well as in patients with various clinical conditions. The aim of this study was to determine whether an attenuation of (Equation is included in full-text article.)O2 occurs above the VT in patients with stable coronary artery disease. METHODS: A total of 33 male patients participating in an outpatient cardiac rehabilitation/secondary prevention program underwent maximal incremental cycle ergometry at increasing pedaling cadences up to the limit of tolerance. Ventilatory gas-exchange variables were measured breath by breath while work rate was recorded continuously. Ventilatory threshold was determined by a dual linear regression model (V-slope analysis). RESULTS: Four patients were excluded from the analysis because they were unable to pedal at the increasing cadences required by the protocol. The remaining 29 patients successfully completed the test without complications or evidence of significant ST segment depression. The slope of the (Equation is included in full-text article.)O2/work rate relationship above the VT decreased significantly (-44.6% on average) in 23 of the 26 patients in which VT was able to be determined. (Equation is included in full-text article.)O2 at the start of (Equation is included in full-text article.)O2 attenuation ((Equation is included in full-text article.)O2att) and at VT were highly correlated and in strong agreement (1637 ± 451 mL/min vs 1650 ± 473 mL/min, r = 0.96, P < .01). CONCLUSIONS: (Equation is included in full-text article.)O2att does occur and coincides with the VT in the majority of patients tested with stable coronary artery disease.

Respiratory muscle training with normocapnic hyperpnea improves ventilatory pattern and thoracoabdominal coordination, and reduces oxygen desaturation during endurance exercise testing in COPD patients.

BACKGROUND: Few data are available about the effects of respiratory muscle training with normocapnic hyperpnea (NH) in COPD. The aim is to evaluate the effects of 4 weeks of NH (Spirotiger(®)) on ventilatory pattern, exercise capacity, and quality of life (QoL) in COPD patients. METHODS: Twenty-six COPD patients (three females), ages 49-82 years, were included in this study. Spirometry and maximal inspiratory pressure, St George Respiratory Questionnaire, 6-minute walk test, and symptom-limited endurance exercise test (endurance test to the limit of tolerance [tLim]) at 75%-80% of peak work rate up to a Borg Score of 8-9/10 were performed before and after NH. Patients were equipped with ambulatory inductive plethysmography (LifeShirt(®)) to evaluate ventilatory pattern and thoracoabdominal coordination (phase angle [PhA]) during tLim. After four supervised sessions, subjects trained at home for 4 weeks - 10 minutes twice a day at 50% of maximal voluntary ventilation. The workload was adjusted during the training period to maintain a Borg Score of 5-6/10. RESULTS: Twenty subjects completed the study. After NH, maximal inspiratory pressure significantly increased (81.5±31.6 vs 91.8±30.6 cmH2O, P<0.01); exercise endurance time (+150 seconds, P=0.04), 6-minute walk test (+30 meters, P=0.03), and QoL (-8, P<0.01) all increased. During tLim, the ventilatory pattern changed significantly (lower ventilation, lower respiratory rate, higher tidal volume); oxygen desaturation, PhA, and dyspnea Borg Score were lower for the same work intensity (P<0.01, P=0.02, and P<0.01, respectively; one-way ANOVA). The improvement in tidal volume and oxygen saturation after NH were significantly related (R (2)=0.65, P<0.01). CONCLUSION: As expected, NH improves inspiratory muscle performance, exercise capacity, and QoL. New results are significant change in ventilatory pattern, which improves oxygen saturation, and an improvement in thoracoabdominal coordination (lower PhA). These two facts could explain the reduced dyspnea during the endurance test. All these results together may play a role in improving exercise capacity after NH training.

Long-term monitoring of oxygen saturation at altitude can be useful in predicting the subsequent development of moderate-to-severe acute mountain sickness.

OBJECTIVE: The use of pulse oximetry (Spo2) to identify subjects susceptible to acute mountain sickness (AMS) is the subject of debate. To obtain more reliable data, we monitored Spo2 for 24 hours at altitude to investigate the ability to predict impending AMS. METHODS: The study was conducted during the climb from Alagna (1154 m) to Capanna Regina Margherita (4559 m), with an overnight stay in Capanna Gnifetti (3647 m). Sixty subjects (11 women) were recruited. Each subject was fitted with a 24-hour recording finger pulse oximeter. The subjects rode a cable car to 3275 m and climbed to 3647 m, where they spent the night. RESULTS: In the morning, 24 subjects (6 women) had a Lake Louise Questionnaire score (LLS) ≥ 3 (AMS(+)), and 15 subjects (4 women) exhibited moderate-to-severe disease (LLS ≥ 5 = AMS(++)). At Alagna, Spo2 did not differ between the AMS(-) and AMS(+) subjects. At higher stations, all AMS(+) subjects exhibited a significantly lower Spo2 than did the AMS(-) subjects: at 3275 m, 85.4% vs 87.7%; resting at 3647 m, 84.5% vs 86.4%. The receiver operating characteristics curve analysis resulted in a rather poor discrimination between the AMS(-) subjects and all of the AMS(+) subjects. With the cutoff LLS ≥ 5, the sensitivity was 86.67%, the specificity was 82.25%, and the area under the curve was 0.88 (P < .0001) for Spo2 ≤ 84% at 3647 m. CONCLUSIONS: We conclude that AMS(+) subjects exhibit a more severe and prolonged oxygen desaturation than do AMS(-) subjects starting from the beginning of altitude exposure, but the predictive power of Spo2 is accurate only for AMS(++).

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.

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 ß-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.