Exercise and the cardiovascular system: clinical science and cardiovascular outcomes

Substantial evidence has established the value of high levels of physical activity, exercise training (ET), and overall cardiorespiratory fitness in the prevention and treatment of cardiovascular diseases. This article reviews some basics of exercise physiology and the acute and chronic responses of ET, as well as the effect of physical activity and cardiorespiratory fitness on cardiovascular diseases. This review also surveys data from epidemiological and ET studies in the primary and secondary prevention of cardiovascular diseases, particularly coronary heart disease and heart failure. These data strongly support the routine prescription of ET to all patients and referrals for patients with cardiovascular diseases, especially coronary heart disease and heart failure, to specific cardiac rehabilitation and ET programs.

Physical activity and cardiorespiratory fitness as major markers of cardiovascular risk: their independent and interwoven importance to health status

The evolution from hunting and gathering to agriculture, followed by industrialization, has had a profound effect on human physical activity (PA) patterns. Current PA patterns are undoubtedly the lowest they have been in human history, with particularly marked declines in recent generations, and future projections indicate further declines around the globe. Non-communicable health problems that afflict current societies are fundamentally attributable to the fact that PA patterns are markedly different than those for which humans were genetically adapted. The advent of modern statistics and epidemiological methods has made it possible to quantify the independent effects of cardiorespiratory fitness (CRF) and PA on health outcomes. Based on more than five decades of epidemiological studies, it is now widely accepted that higher PA patterns and levels of CRF are associated with better health outcomes. This review will discuss the evidence supporting the premise that PA and CRF are independent risk factors for cardiovascular disease (CVD) as well as the interplay between both PA and CRF and other CVD risk factors. A particular focus will be given to the interplay between CRF, metabolic risk and obesity.

Effect of If-channel inhibition on hemodynamic status and exercise tolerance in heart failure with preserved ejection fraction: a randomized trial

OBJECTIVES

The aim of this study was to test the effects of treatment with ivabradine on exercise capacity and left ventricular filling in patients with heart failure with preserved ejection fraction (HFpEF).

BACKGROUND

Because symptoms of HFpEF are typically exertional, optimization of diastolic filling time by controlling heart rate may delay the onset of symptoms.

METHODS

Sixty-one patients with HFpEF were randomly assigned to ivabradine 5 mg twice daily (n = 30) or placebo (n = 31) for 7 days in this double-blind trial. Cardiopulmonary exercise testing with echocardiographic assessment of myocardial function and left ventricular filling were undertaken at rest and after exercise.

RESULTS

The ivabradine group demonstrated significant improvement between baseline and follow-up exercise capacity (4.2 ± 1.8 METs vs. 5.7 ± 1.9 METs, p = 0.001) and peak oxygen uptake (14.0 ± 6.1 ml/min/kg vs. 17.0 ± 3.3 ml/min/kg, p = 0.001), with simultaneous reduction in exercise-induced increase in the ratio of peak early diastolic mitral flow velocity to peak early diastolic mitral annular velocity (3.1 ± 2.7 vs. 1.3 ± 2.0, p = 0.004). Work load-corrected chronotropic response (the difference in heart rate at the same exercise time at the baseline and follow-up tests) showed a slower increase in heart rate during exercise than in the placebo-treated group. Therapy with ivabradine (β = 0.34, p = 0.04) and change with treatment in exertional increase in the ratio of peak early diastolic mitral flow velocity to peak early diastolic mitral annular velocity (β = -0.30, p = 0.02) were independent correlates of increase in exercise capacity, and therapy with ivabradine (β = 0.32, p = 0.007) was independently correlated with increase in peak oxygen uptake.

CONCLUSIONS

In patients with HFpEF, short-term treatment with ivabradine increased exercise capacity, with a contribution from improved left ventricular filling pressure response to exercise as reflected by the ratio of peak early diastolic mitral flow velocity to peak early diastolic mitral annular velocity. Because this patient population is symptomatic on exertion, therapeutic treatments targeting abnormal exercise hemodynamic status may prove useful. (Use of Exercise and Medical Therapies to Improve Cardiac Function Among Patients With Exertional Shortness of Breath Due to Lung Congestion; ACTRN12610001087044).

Contribution of cardiorespiratory fitness to the obesity paradox

Until recently, cardiorespiratory fitness (CRF) has been overlooked as a potential modifier of the inverse association between obesity and mortality (the so-called obesity paradox), observed in patients with known or suspected cardiovascular (CV) disease. Evidence from five observational cohort studies of 30,104 patients (87% male) with CV disease indicates that CRF significantly alters the obesity paradox. There is general agreement across studies that the obesity paradox persists among patients with low CRF, regardless of whether adiposity is assessed by body mass index, waist circumference, or percentage body fat. However, among patients with high CRF, risk of all-cause mortality is lowest for the overweight category in some, but not all, studies, suggesting that higher levels of fitness may modify the relationship between body fatness and survival in patients manifesting an obesity paradox. Further study is needed to better characterize the joint contribution of CRF and obesity on mortality in diverse populations.

The effect of resistance exercise on all-cause mortality in cancer survivors

OBJECTIVE

To examine the independent associations of leisure-time aerobic physical activity (PA) and resistance exercise (RE) on all-cause mortality in cancer survivors.

PATIENTS AND METHODS

Patients included 2863 male and female cancer survivors, aged 18 to 81 years, who received a preventive medical examination between April 8, 1987, and December 27, 2002, while enrolled in the Aerobics Center Longitudinal Study in Dallas, Texas. Physical activity and RE were assessed by self-report at the baseline medical examination. Cox proportional hazards regression analysis was performed to determine the independent associations of PA and RE with all-cause mortality in participants who had a history of cancer.

RESULTS

Physical activity in cancer survivors was not associated with a lower risk of all-cause mortality. In contrast, RE was associated with a 33% lower risk of all-cause mortality (95% CI, 0.45-0.99) after adjusting for potential confounders, including PA.

CONCLUSION

Individuals who participated in RE during cancer survival had a lower risk for all-cause mortality. The present findings provide preliminary evidence for benefits of RE during cancer survival. Future randomized controlled trials examining RE and its effect on lean body mass, muscular strength, and all-cause mortality in cancer survivors are warranted.

Evaluation of cardiorespiratory fitness and respiratory muscle function in the obese population

Cardiorespiratory fitness (CRF) is one of the most important health metrics in apparently healthy individuals, those at increased risk for cardiovascular (CV) disease and virtually all patient populations. In addition to CRF, a host of other variables obtained from aerobic exercise testing provides clinically valuable information. Individuals classified as obese (i.e. a body mass index ≥30 kg/m(2)) have varying degrees of CV, pulmonary and skeletal muscle dysfunction that impact CRF and other key aerobic exercise testing variables. Moreover, there is now evidence indicating inspiratory and expiratory respiratory muscle function, even in the absence of interstitial lung disease, is potentially compromised as a result of obesity. When obesity-induced respiratory muscle dysfunction is present, it has the potential to contribute to the limitations in CRF. The current review will discuss aerobic exercise testing and the assessment of respiratory muscle function in the obese population.

Measuring physical activity in pregnancy: a comparison of accelerometry and self-completion questionnaires in overweight and obese women

OBJECTIVES

Increased physical activity in pregnancy may reduce the risk of gestational diabetes and pre-eclampsia, which occur more commonly in overweight and obese women. There is limited assessment of physical activity questionnaires in pregnancy. This study compares self-reported physical activity using two questionnaire methods with objectively recorded physical activity using accelerometry in overweight and obese pregnant women.

STUDY DESIGN

59 women with booking BMI≥25 kg/m(2) completed the Recent Physical Activity Questionnaire (RPAQ) and Australian Women's Activity Survey (AWAS) or recorded at least 3 days of accelerometry at median 12 weeks' gestation. Accelerometer thresholds of 100 counts/min and 1952 counts/min were used to define light and moderate or vigorous physical activity (MVPA) respectively.

RESULTS

48% of women were in their first pregnancy and 41% were obese. Median daily self-reported MVPA was significantly higher for both AWAS (127 min, p<0.001) and RPAQ (81 min, p<0.001) than that recorded by accelerometer (35 min). There was low or moderate correlation between questionnaire and accelerometer estimates of total active time (AWAS ρ=0.36, p=0.008; RPAQ ρ=0.53, p<0.001) but no significant correlation between estimates of time spent in MVPA.

CONCLUSIONS

These self-report questionnaires over-estimated MVPA and showed poor ability to discriminate women on the basis of MVPA. Accelerometry measurement was feasible and acceptable. Objective methods should be used where possible in studies measuring physical activity in pregnancy. Questionnaires remain valuable to define types of activity.

Is the SenseWear Armband accurate enough to quantify and estimate energy expenditure in healthy adults?

BACKGROUND

The SenseWear Armband (SWA) is a monitor that can be used to estimate energy expenditure (EE); however, it has not been validated in healthy adults. The objective of this paper was to study the validity of the SWA for quantifying EE levels.

METHODS

Twenty-three healthy adults (age 40-55 years, mean: 48±3.42 years) performed different types of standardized physical activity (PA) for 10 minutes (rest, walking at 3 and 5 km·h^-1, running at 7 and 9 km·h^-1, and sitting/standing at a rate of 30 cycle·min^-1). Participants wore the SWA on their right arm, and their EE was measured by indirect calorimetry (IC) the gold standard.

RESULTS

There were significant differences between the SWA and IC, except in the group that ran at 9 km·h^-1 (>9 METs). Bland-Altman analysis showed a BIAS of 1.56 METs (±1.83 METs) and limits of agreement (LOA) at 95% of -2.03 to 5.16 METs. There were indications of heteroscedasticity (R² =0.03; P<0.05). Analysis of the receiver operating characteristic (ROC) curves showed that the SWA seems to be not sensitive enough to estimate the level of EE at highest intensities.

CONCLUSIONS

The SWA is not as precise in estimating EE as IC, but it could be a useful tool to determine levels of EE at low intensities.

Interaction of physical activity and interoception in children

Background: Physical activity (PA) is associated with positive health outcomes, whereas physical inactivity is related to an increased risk for various health issues including obesity and cardiovascular diseases. Previous research indicates that interindividual differences in the perception of bodily processes (interoceptive sensitivity, IS) interact with the degree of PA in adults. Whether there is a similar relationship between PA and IS in children has not been investigated yet. Therefore, the aim of this study was to investigate the interaction between IS and PA during physical performance tasks and in everyday situations. Methods: IS was assessed using a heartbeat perception task in a sample of 49 children within the health promotion program “Join the Healthy Boat” which is implemented in several primary schools in the southwest of Germany. PA was examined using a physical performance task, assessing the distance covered during a standardized 6-min run. In a subsample of 21 children, everyday PA was measured by a multi-sensor device (Actiheart, CamNtech, Cambridge, UK) during five consecutive days with more than 10 h of daily data collection. Results: Children with higher IS performed better in the physical performance task. Additionally, based on energy expenditure defined as metabolic equivalents, IS was positively correlated with the extent of light PA levels in the morning and afternoon. Conclusion: Our findings reveal that IS interacts positively with the degree of PA in children supporting the idea that interoception is important for the self-regulation of health-related behavior.

Exercise stress test in apparently healthy individuals - where to place the finish line? The Ferrari corporate wellness programme experience

AIMS

The aim of our study was to assess the clinical significance of the exercise stress testing endpoints, namely 85% of maximal theoretical heart rate (MTHR), metabolic equivalent of task, and rating of perceived exertion (RPE), and their relation to electrocardiographic (ECG) changes in a healthy adult population.

METHODS

A cross-sectional study was conducted on 408 males and 52 females (mean age 39.4 ± 8.6 years) who performed the maximal cycle ergometer exercise stress test until volitional exhaustion, reporting the RPE score at 85% of MTHR and at peak exercise. Metabolic equivalents of task were indirectly calculated from the maximum workload and compared with the predicted values. Sitting torso-lead ECG and blood pressure were recorded at rest, during exercise and during recovery.

RESULTS

Of 460 participants, 73% exceeded 85% of MTHR. The RPE score represented the overall most significant endpoint of exercise stress testing, with the median value of 17 at peak exercise. ECG events were detected in 23/124 (18.5%) who reached ≤ 85% of MTHR and in 61/336 (18.2%) who achieved >85% of MTHR ( p = 0.92). In the latter group, 54% of ECG changes occurred at < 85% of MTHR and 46% at > 85% of MTHR ( p = 0.51). If the exercise stress testing had been interrupted at ≤ 85% of MTHR, almost half of the ECG events would have remained undetected and 35% of the cardiovascular abnormalities observed at the diagnostic follow-up would have remained undiagnosed.

CONCLUSION

Terminating exercise stress testing before volitional exhaustion and an RPE score of 17 limits the test accuracy and reduces the possibility to detect cardiovascular abnormalities in apparently healthy adult populations.

Occupational Physical Activity and New-Onset Hypertension: A Nationwide Cohort Study in China

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Effect of a postoperative outpatient pulmonary rehabilitation program on physical activity in patients who underwent pulmonary resection for lung cancer

AIM

Physical activity (PA) has been associated with an improvement in survival for individuals with cancer. However, little is known about the effect of postoperative pulmonary rehabilitation on PA after lobectomy in patients with lung cancer. The present study investigated the effect of outpatient rehabilitation on PA in patients with cancer after lung resection.

METHODS

A total of 19 patients with lung cancer were recruited for this study and completed a preoperative rehabilitation program. One group of nine patients completed a postoperative outpatient pulmonary rehabilitation program (rehabilitation) and another group of 10 patients did not (control), but were similarly followed up. Preoperative lung function, assessed by forced expiratory volume in 1 s (FEV1 ), body mass index (BMI) and St. George's Respiratory Questionnaire (SGRQ) score were not different between groups. PA was measured before and 2 months after surgery using a three-axis accelerometer for 5-6 days. PA level (PAL) was defined as total energy expenditure divided by basal metabolic rate.

RESULTS

Preoperative PAL was not different between groups. However, postoperative versus preoperative PAL was significantly lower in the control versus the rehabilitation group (P < 0.01), and PAL decline was less for the rehabilitation versus the control group (P < 0.001). A subgroup analysis showed improvement in postoperative PAL in rehabilitation patients aged <75 years and older.

CONCLUSIONS

Two months after lung resection surgery, patients had not recovered to the preoperative PAL. However, compared with the control group, there was an improvement in the postoperative PAL in patients, including older patients, who underwent outpatient pulmonary rehabilitation. Geriatr Gerontol Int 2016; 16: 550-555.

Metabolic equivalents of task are confounded by adiposity, which disturbs objective measurement of physical activity

Physical activity refers any bodily movements produced by skeletal muscles that expends energy. Hence the amount and the intensity of physical activity can be assessed by energy expenditure. Metabolic equivalents of task (MET) are multiplies of the resting metabolism reflecting metabolic rate during exercise. The standard MET is defined as 3.5 ml/min/kg. However, the expression of energy expenditure by body weight to normalize the size differences between subjects causes analytical hazards: scaling by body weight does not have a physiological, mathematical, or physical rationale. This review demonstrates by examples that false methodology may cause paradoxical observations if physical activity would be assessed by body weight scaled values such as standard METs. While standard METs are confounded by adiposity, lean mass proportional measures of energy expenditure would enable a more truthful choice to assess physical activity. While physical activity as a behavior and cardiorespiratory fitness or adiposity as a state represents major determinants of public health, specific measurements of health determinants must be understood to enable a truthful evaluation of the interactions and their independent role as a health predictor.

Metabolic syndrome and right ventricle: an updated review

The cluster of metabolic and hemodynamic abnormalities which characterize the metabolic syndrome (MS) is responsible for subclinical cardiac and extra-cardiac damage such as left ventricular hypertrophy, diastolic dysfunction, carotid atherosclerosis and microalbuminuria. The development of different non-invasive imaging methods enabled a detail investigation of right ventricular structure and function, and revealed that right ventricular remodeling followed changes in the left ventricular structure and function in patients with arterial hypertension, diabetes or obesity. Previous investigations also reported that the coexistence of two components of the MS induced more significant cardiac remodeling than the presence of only one MS risk-factor. The relationship between different components of the MS (increased blood pressure, abdominal obesity, increased fasting glucose level and dyslipidemia) and right ventricular remodeling could be explained by several hemodynamic and non-hemodynamic mechanisms. However, the association between right ventricular remodeling and the MS has not been sufficiently investigated so far. The aim of this article was to review recent articles focusing on the association between metabolic syndrome components and the metabolic syndrome itself with impairments in right ventricular structure and function assessed by different imaging techniques.

Accuracy of Samsung Gear S Smartwatch for Activity Recognition: Validation Study

Background

Wearable accelerometers have greatly improved measurement of physical activity, and the increasing popularity of smartwatches with inherent acceleration data collection suggest their potential use in the physical activity research domain; however, their use needs to be validated.

Objective

This study aimed to assess the validity of accelerometer data collected from a Samsung Gear S smartwatch (SGS) compared with an ActiGraph GT3X+ (GT3X+) activity monitor. The study aims were to (1) assess SGS validity using a mechanical shaker; (2) assess SGS validity using a treadmill running test; and (3) compare individual activity recognition, location of major body movement detection, activity intensity detection, locomotion recognition, and metabolic equivalent scores (METs) estimation between the SGS and GT3X+.

Methods

To validate and compare the SGS accelerometer data with GT3X+ data, we collected data simultaneously from both devices during highly controlled, mechanically simulated, and less-controlled natural wear conditions. First, SGS and GT3X+ data were simultaneously collected from a mechanical shaker and an individual ambulating on a treadmill. Pearson correlation was calculated for mechanical shaker and treadmill experiments. Finally, SGS and GT3X+ data were simultaneously collected during 15 common daily activities performed by 40 participants (n=12 males, mean age 55.15 [SD 17.8] years). A total of 15 frequency- and time-domain features were extracted from SGS and GT3X+ data. We used these features for training machine learning models on 6 tasks: (1) individual activity recognition, (2) activity intensity detection, (3) locomotion recognition, (4) sedentary activity detection, (5) major body movement location detection, and (6) METs estimation. The classification models included random forest, support vector machines, neural networks, and decision trees. The results were compared between devices. We evaluated the effect of different feature extraction window lengths on model accuracy as defined by the percentage of correct classifications. In addition to these classification tasks, we also used the extracted features for METs estimation.

Results

The results were compared between devices. Accelerometer data from SGS were highly correlated with the accelerometer data from GT3X+ for all 3 axes, with a correlation ≥.89 for both the shaker test and treadmill test and ≥.70 for all daily activities, except for computer work. Our results for the classification of activity intensity levels, locomotion, sedentary, major body movement location, and individual activity recognition showed overall accuracies of 0.87, 1.00, 0.98, 0.85, and 0.64, respectively. The results were not significantly different between the SGS and GT3X+. Random forest model was the best model for METs estimation (root mean squared error of .71 and r-squared value of .50).

Conclusions

Our results suggest that a commercial brand smartwatch can be used in lieu of validated research grade activity monitors for individual activity recognition, major body movement location detection, activity intensity detection, and locomotion detection tasks.

Characteristics and outcomes of patients who achieve high workload (≥10 metabolic equivalents) during treadmill exercise echocardiography

OBJECTIVE

To determine the frequency and prognostic significance of abnormal exercise echocardiographic results for patients achieving a workload of 10 or more metabolic equivalents during treadmill exercise echocardiography.

PATIENTS AND METHODS

Patients who underwent treadmill exercise echocardiography from November 1, 2003, through December 31, 2008, and exercised for 9 or more minutes using the Bruce protocol (N=7236) were included. Clinical and exercise echocardiographic characteristics and outcomes were evaluated. Variables associated with abnormal exercise echocardiographic results and mortality were identified.

RESULTS

Exercise echocardiographic results were positive for ischemia in 862 patients (12%). Extensive ischemia developed in 265 patients (4%). For patients with normal exercise echocardiographic results, all-cause and cardiovascular mortality rates were 0.30% and 0.05% per person-year of follow-up, respectively. For patients who had extensive ischemia, all-cause and cardiovascular mortality rates were 0.84% and 0.25% per person-year of follow-up, respectively. Patients at highest risk were those who had extensive and severe regional wall motion abnormalities at rest (n=58), and their all-cause and cardiovascular mortality rates were 2.65% and 0.76% per person-year of follow-up. Exercise echocardiographic variables did not identify sizable patient subgroups at risk for death and did not provide incremental prognostic information (C statistic was 0.74 compared with 0.73 for the clinical plus exercise electrocardiography model).

CONCLUSION

Patients achieving a workload of 10 or more metabolic equivalents during treadmill exercise testing do not often have extensive ischemic abnormalities on exercise echocardiography. Although exercise echocardiographic results provide some prognostic information, it is not of incremental value for these patients, whose short-term and medium-term prognosis is excellent.

Dose-response association of physical activity with acute myocardial infarction: do amount and intensity matter?

OBJECTIVE

The aims of this study were to analyze the dose-response association between leisure time physical activity (PA) practice and myocardial infarction (MI), considering not only the total amount but also the amount of PA at different levels of intensity, and to determine whether these associations were modified by age.

METHOD

In a population-based age- and sex-matched case-control study, all first acute MI patients aged 25 to 74 years were prospectively registered in four Spanish hospitals between 2002 and 2004. Controls were randomly selected from population-based samples recruited during the same period of time. The Minnesota PA questionnaire was administered to assess total energy expenditure in PA and in light-, moderate-, and high-intensity PA.

RESULTS

Finally, 1339 cases and 1339 controls were included. The association between PA and MI likelihood was non-linear, with significantly lower MI odds at low practice levels (≥ 500 MET·min/week), lowest odds around 1500 MET·min/week, and a plateau thereafter. Light- (in subjects older than 64 years), moderate-, and high-intensity PA produced similar benefits.

CONCLUSION

Most of the population could reduce their likelihood of MI by engaging in PA at a moderate level of intensity or, in individuals older than 64 years, at a light level of intensity.

Walking and Calcified Atherosclerotic Plaque in the Coronary Arteries: The National Heart, Lung, and Blood Institute Family Heart Study

OBJECTIVE

Studies have reported mixed findings on the association between physical activity and subclinical atherosclerosis. We sought to examine whether walking is associated with prevalent coronary artery calcification (CAC) and aortic calcification.

APPROACH AND RESULTS

In a cross-sectional design, we studied 2971 participants of the National Heart, Lung, and Blood Institute Family Heart Study without a history of myocardial infarction, coronary artery bypass grafting, or percutaneous transluminal angioplasty. A standardized questionnaire was used to ascertain the number of blocks walked daily to compute walking metabolic equivalent hours. CAC was measured by cardiac computed tomography. We defined prevalent CAC and aortic calcification using an Agatston score of at least 100 and used generalized estimating equations to calculate adjusted prevalence ratios. Mean age was 55 years, and 60% of participants were women. Compared with the ≤3.75-Met-h/wk group, prevalence ratios for CAC after adjusting for age, sex, race, smoking, alcohol use, total physical activity (excluding walking), and familial clustering were 0.53 (95% confidence interval, 0.35-0.79) for >3.75 to 7.5 Met-h/wk, 0.72 (95% confidence interval, 0.52-0.99) for >7.5 to 15 Met-h/wk, and 0.54 (95% confidence interval, 0.36-0.81) for >15 to 22.5 Met-h/wk, (P trend=0.01). The walking-CAC relationship remained significant for those with body mass index ≥25 (P trend=0.02) and persisted with CAC cutoffs of 300, 200, 150, and 50 but not 0. When examined as a continuous variable, a J-shaped association between walking and CAC was found. The walking-aortic calcification association was not significant.

CONCLUSIONS

Our findings suggest that walking is associated with lower prevalent CAC (but not aortic calcification) in adults without known heart disease.

Metabolic Equivalent in Adolescents, Active Adults and Pregnant Women

“Metabolic Equivalent” (MET) represents a standard amount of oxygen consumed by the body under resting conditions, and is defined as 3.5 mL O₂/kg × min or ~1 kcal/kg × h. It is used to express the energy cost of physical activity in multiples of MET. However, universal application of the 1-MET standard was questioned in previous studies, because it does not apply well to all individuals. Height, weight and resting metabolic rate (RMR, measured by indirect calorimetry) were measured in adolescent males (n = 50) and females (n = 50), women during pregnancy (gestation week 35–41, n = 46), women 24–53 weeks postpartum (n = 27), and active men (n = 30), and were compared to values predicted by the 1-MET standard. The RMR of adolescent males (1.28 kcal/kg × h) was significantly higher than that of adolescent females (1.11 kcal/kg × h), with or without the effects of puberty stage and physical activity levels. The RMR of the pregnant and post-pregnant subjects were not significantly different. The RMR of the active normal weight (0.92 kcal/kg × h) and overweight (0.89 kcal/kg × h) adult males were significantly lower than the 1-MET value. It follows that the 1-MET standard is inadequate for use not only in adult men and women, but also in adolescents and physically active men. It is therefore recommended that practitioners estimate RMR with equations taking into account individual characteristics, such as sex, age and Body Mass Index, and not rely on the 1-MET standard.

Predictors of cardiorespiratory fitness improvement in phase II cardiac rehabilitation

BACKGROUND

Cardiac rehabilitation (CR) improves cardiorespiratory fitness (CRF) and has been shown to reduce cardiovascular events and death. However, data about predictors of fitness improvement during CR are limited and conflicting. The objective of this study was to determine predictors of improvement in metabolic equivalents of task (METs) based on formal exercise testing throughout phase II CR.

METHODS

We retrospectively reviewed 20 671 patients enrolled in phase II CR at our center from 2006 to 2016. Patients who completed 36 sessions and had entry and exit exercise stress tests were included for study. The short form-36 (SF-36) questionnaire was used to assess quality-of-life. Univariate and multivariate regression analyses were performed to determine independent predictors of METs improvement.

RESULTS

Of the full cohort, 827 patients completed 36 sessions and had entry/exit stress test data. The majority of patients (N = 647, 78.2%) had improvement in METs (mean Δ 2.0 ± 1.2 METs), including patients ≥65 and < 65 years old (77% vs 79%, P = 0.46 for difference). METs improvement was negatively associated with body mass index, diabetes, left ventricular dysfunction, and poor baseline fitness; and positively associated with SF-36 score (P < 0.05 for all). After multivariable adjustment, improvement was no longer affected by age, ejection fraction, or baseline fitness. Patients with poor fitness (≤5 METS) and adequate fitness (> 5 METS) both had improvement, with no statistical difference between the groups (P = 0.36).

CONCLUSIONS

In a large cohort of phase II CR patients, improvement in CRF was seen in the majority of patients across all ages, genders, and levels of baseline fitness.

Physical Activity of the Population of the Most Obese Country in Europe, Hungary

Introduction: Physical activity is inversely proportional to mortality, so it has an important role in disease prevention. The aim of our study was to characterize the physical activity of Hungarians, the most obese population in Europe. Materials and methods: In a cross-sectional study the physical activity of the Hungarian population was characterized in a sample (n = 1,295) which was representative of the sex, age and geographical location of the adult population aged 18 years and above by using the long form of the International Physical Activity Questionnaires (IPAQ) as an instrument. Based on the metabolic equivalent (MET) rates three categories of physical activity (low, moderate, and high) were defined. Two-step cluster analysis was used to explore physical activity characteristics of participants using sex, age, settlement type and BMI categories as categorical variables, and MET values related to the Work, Transportation, Domestic and Garden, and Leisure Time domains of physical activity as continuous variables. Results: The study showed that 63.39% of the adult Hungarian population took part in high, and 24.78% in moderate activity, and only 11.73% of the sample belonged to the category of low physical activity. By cluster analysis six clusters of people with typical lifestyles could be identified in the Hungarian adult population. In all the six groups participants achieved moderate or high activity levels through work and housework. Physical activity in relation to transportation is very low, similarly to leisure-time sporting activities. In the case of elder people, severe overweight/obesity problems can be detected in married city-dwellers. Discussion: Although Hungary has the highest obesity rate in Europe our research has proved that Hungarians lead physically active lives. The dominant forms of their physical activity are linked to work and housework. Our findings draw attention to the need to examine other risk factors in addition to physical inactivity. Our findings also suggest that the type of physical activity should be more severely considered when defining factors protective against obesity.

Cardiorespiratory responses in different types of squats and frequencies of whole body vibration in patients with chronic obstructive pulmonary disease

This study aims to investigate the cardiorespiratory responses to different vibration frequencies to characterize the intensity of exercise, as well as to compare the effect of two types of squatting exercises (static and dynamic) on the whole body vibration (WBV) exercise in individuals with chronic obstructive pulmonary disease (COPD). Twenty-six subjects were divided and paired into healthy and COPD groups that performed static squatting associated with WBV (frequencies: 30, 35, and 40 Hz; amplitude: 2 mm) and dynamic squatting associated with WBV (frequency: 35 Hz; amplitude 2 mm) on a vertical vibration platform. Oxygen consumption (V̇o₂), heart rate (HR), minute ventilation (V̇e), ratio of minute ventilation to oxygen production (V̇e/V̇o₂), ratio of minute ventilation to carbon dioxide production (V̇e/V̇co₂), oxygen saturation (SpO₂), and rating of perceived exertion were measured. For both groups, there was a decrease in V̇e/V̇o₂ and V̇e/V̇co₂ ratios during static and dynamic squats, as well as an increase in other cardiorespiratory parameters, and no significant difference existed between them. There was an effect of the type of squat on the HR variation; the values in the static squat were higher than those of the dynamic squat in both groups. There was a significant difference with a reduction in SpO₂ at 40 Hz frequency when compared with 30 Hz in the COPD group. The other variables behaved similarly between the frequencies. The WBV exercise, regardless of the frequencies used, represented a mild effort that promoted cardiorespiratory response in COPD, with greater responses in the static squat and no adverse effect. NEW & NOTEWORTHY This study showed that an acute session of light exercise of whole body vibration (WBV) can increase the cardiorespiratory responses in patients with chronic obstructive pulmonary disease (COPD), reaching values similar to that of the control group. The results might contribute, therefore, to the elaboration of exercise protocols with WBV for the treatment of patients with COPD during rehabilitation. Thus, future studies referring to training on the vibratory platform could use these exercise parameters and demonstrate possible long-term benefits.

Use of functional aerobic capacity based on stress testing to predict outcomes in normal, overweight, and obese patients

OBJECTIVE

To determine the poorly studied relationship between functional aerobic capacity (FAC) as measured by treadmill stress testing and mortality in normal, overweight, and obese patients.

PATIENTS AND METHODS

Patients were identified retrospectively from the stress testing database at Mayo Clinic in Rochester, Minnesota. We selected 5328 male nonsmokers (mean ± SD age, 51.8±11.5 years) without baseline cardiovascular disease who were referred for treadmill exercise testing between January 1, 1986, and December 31, 1991, and classified them by body mass index (BMI) into normal-weight (18.5-24.9 kg/m(2)), overweight (25.0-29.9 kg/m(2)), and obese (≥30 kg/m(2)) categories. Functional aerobic capacity was assessed by maximal exercise test results based on age- and sex-specific metabolic equivalents, and patients were stratified into fitness quintiles. Cox proportional hazards analysis was used to determine the relationship of all-cause mortality to fitness in each BMI category.

RESULTS

There were 322 deaths during 14 years of follow-up. After adjustment for age and exercise confounders, FAC predicted mortality in the 3 BMI groups. Hazard ratios for FAC less than 80% of predicted vs a reference group with normal BMI and fitness (FAC ≥100%) were 1.754 (95% CI, 0.874-3.522), 1.962 (1.356-2.837), and 1.518 (1.056-2.182) for the normal, overweight, and obese groups, respectively. The CIs of the hazard ratios overlapped with no statistically significant differences (P>.05).

CONCLUSION

A significant increase in mortality occurs with FAC below 80% of predicted for overweight and obese subjects and below 70% for normal weight subjects. Our results suggest that clinicians need not adjust the standard for low fitness in obese patients.

Intake Duration of Anthocyanin-Rich New Zealand Blackcurrant Extract Affects Metabolic Responses during Moderate Intensity Walking Exercise in Adult Males

We examined effects of intake duration of anthocyanin-rich New Zealand blackcurrant (NZBC) extract on physiological and metabolic responses during moderate intensity walking. Healthy men (n = 16, age: 24 ± 6 years, body mass: 78 ± 16 kg, BMI: 24.7 ± 4.1 kg·m^-2, body fat: 15 ± 5%) volunteered. One metabolic equivalent (1-MET: 3.95 ± 0.64 ml·kg^-1·min^-1) was measured during supine rest. Responses during the 30-min walk (n = 3: 4-MET; n = 13: 5-MET) (speed: 5.7 ± 0.7 km·hr^-1) were measured at 7-10, 17-20 and 27-30 min and averaged over the time periods. For intake conditions (7-days and 14-days), two capsules of NZBC extract (600 mg containing 210 mg of anthocyanins) were taken with breakfast (14-day washout). The final two capsules were ingested 2-hr before the morning walk. Intake duration of NZBC extract had no effect on heart rate, minute ventilation, oxygen uptake, and carbon dioxide production. Fat oxidation was enhanced with 7- and 14-day intake by 11 ± 19% and 17 ± 26% (baseline: 0.36 ± 0.12, 7-day: 0.39 ± 0.13, 14-day: 0.41 ± 0.13 g·min^-1, p = 0.007). Only 14-day intake lowered RER (baseline: 0.852 ± 0.046, 7-day: 0.843 ± 0.045, 14-day: 0.837 ± 0.037, p = 0.019) and carbohydrate oxidation (baseline: 0.95 ± 0.40, 7-day: 0.91 ± 0.40, 14-day: 0.86 ± 0.33 g·min^-1, p = 0.032). Rating of perceived exertion was lower with 7-day and 14-day intake (baseline: 11.0 ± 2.3, 7-day: 10.5 ± 1.8, 14-day: 10.3 ± 2.1, p = 0.002). Longer intake duration (i.e. 14 days) of New Zealand blackcurrant extract seems to enhance fat oxidation more during a 30-min moderate intensity walk than 7 days intake. The intake duration of anthocyanin-rich New Zealand blackcurrant extract may be due to an enhanced bioavailability of anthocyanin-derived metabolites that alter the mechanisms for substrate oxidation during moderate intensity exercise.

Cross-sectional association of physical activity and periodontal antibodies

BACKGROUND

The objective of this study was to evaluate the cross-sectional association between physical activity and serum IgG antibodies against selected periodontal microorganisms.

METHODS

The study population consisted of 5,611 randomly selected US adults who participated in the National Health and Nutrition Examination Survey (NHANES) III (1988 to 1994), who were 40 years and older with complete IgG antibody data against 19 oral microorganisms. We used cluster analysis to classify the 19 antibody titers into 4 mutually exclusive groups called "Orange-Red," "Red-Green," "Yellow- Orange," and "Orange-Blue," and calculated cluster scores by summing antibody titer z-scores for each of the four groups. Physical activity was evaluated based on reported frequency and intensity of physical activity conducted in the last month. Participants were grouped into three categories: adequately physically active, inadequately physically active, and inactive. The outcomes were IgG cluster scores with physical activity as the predictor. Multivariable models adjusted for age, sex, race, smoking status, waist circumference, education, poverty-income-ratio, alcohol, and diabetes.

RESULTS

In adjusted models, physical activity was positively associated with the antibodies in the Orange-Blue cluster (E. nodatum, A. naeslundii), a cluster that is associated with healthy periodontal states. The mean differences in cluster scores were 15.2 (95% CI -1.0, 31.4) for Model 3, and 7.0 (95% CI -8.3, 22.3) for Model 4 comparing the sufficiently active group to the inactive group.

CONCLUSIONS

Antibody titers against periodontal microorganisms reflecting good oral health trended higher among physically active individuals, but the results were not statistically significant at the 0.05 level.