Effects of Home-Based Exercise Training Systems, Combined with Diet, on Cardiometabolic Health.

The efficacy of exercise training systems designed to be used in the home on cardiometabolic outcomes remains largely unknown. This investigation included two studies. Study 1 tested the effects a multi-exercise pulley system (NordicTrack Fusion CST with video trainer) and Study 2 an incline trainer (NordicTrack X22i with video trainer), both combined with daily food provision, for 12-weeks on indices of cardiometabolic health. Study 1 enrolled 27 adults (11 men, 16 women, 33.8±4.4 years of age) and Study 2 enrolled 29 adults (11 men, 18 women, 40.8±12.5 years of age). Pre- and post-intervention measurements were performed for body weight, fat mass, lean tissue mass, and visceral fat by dual energy x-ray absorptiometry, blood pressure, aerobic fitness and body circumferences. For Study 1, there were significant decreases in body weight, fat mass, visceral fat, diastolic blood pressure (DBP), resting heart rate (RHR), and all circumference sites, while there was an increase in aerobic fitness (all p<0.001). Both males and females exhibited significant improvement in all these outcomes. For Study 2, there were significant decreases in body weight, fat mass, visceral fat, DBP, RHR, all circumference sites (all p<0.001), and lean tissue mass (LTM) (p=0.006), and an increase in aerobic fitness (p<0.001). Both males and females exhibited significant changes in all these outcomes, except LTM which did not change in females. Both studies exhibited high exercise session attendance and high dietary adherence. Overall these data indicate the potential efficacy of home-based training systems, when combined with diet, on selected cardiometabolic outcomes.

Rats Selectively Bred for High Voluntary Physical Activity Behavior are Not Protected from the Deleterious Metabolic Effects of a Western Diet When Sedentary.

BACKGROUND: Physical activity and diet are well-established modifiable factors that influence chronic disease risk. We developed a selectively bred, polygenic model for high and low voluntary running (HVR and LVR, respectively) distances. After 8 generations, large differences in running distance were noted. Despite these inherent behavioral differences in physical activity levels, it is unknown whether HVR rats would be inherently protected from diet-induced metabolic dysfunction. OBJECTIVES: The aim of this study was to determine whether HVR rats without voluntary running wheels would be inherently protected from diet-induced metabolic dysfunction. METHODS: Young HVR, LVR, and a wild-type (WT) control group were housed with no running wheel access and fed either a normal diet (ND) or a high-sugar/fat Western diet (WD) for 8 wk. Body weight, percentage body fat (by dual-energy X-ray absorptiometry scan), blood lipids [total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides (TGs), nonesterified fatty acids], and hepatic TG content were measured, and indices of insulin sensitivity were determined via an intravenous glucose tolerance test. Additionally, weekly energy intake and feed efficiency were calculated. RESULTS: After 8 wk, significant differences in body weight and body fat percentage were noted in all WD animals compared with ND animals, with the LVR-WD exhibiting the greatest increase due, in part, to their enhanced feed efficiency. Lipid dysregulation was present in all WD rat lines compared with ND counterparts. Furthermore, LVR-WD rats had higher total cholesterol, HDL cholesterol, and TG concentrations, and higher areas under the curve (AUC) for insulin than HVR-WD and WT-WD, although HVR-WD animals had higher AUCglucose than both LVR-WD and WT-WD and higher LDL than WT-WD. CONCLUSIONS: In the absence of high voluntary running behavior, the genetic predisposition for high running in HVR did not largely protect them from the deleterious effects of a WD compared with LVR, suggesting genetic factors influencing physical activity levels may, in part, be independent from genes influencing metabolism.

Resistance-exercise training ameliorates LPS-induced cognitive impairment concurrent with molecular signaling changes in the rat dentate gyrus.

Effective treatments preventing brain neuroinflammatory diseases are lacking. Resistance-exercise training (RT) ameliorates mild cognitive impairment (MCI), a forerunner to neuroinflammatory diseases. However, few studies have addressed the molecular basis by which RT abates MCI. Thus experiments were performed to identify some molecular changes occurring in response to RT in young, female Wistar rats. To induce MCI, intraventricular lipopolysaccharide (LPS) injections were used to increase dentate gyrus inflammation, reflected by significantly increased TNF-α (~400%) and IL-1ß (~1,500%) mRNA (P < 0.0001) after 6 wk. Five days after LPS injections, half of LPS-injected rats performed RT by ladder climbing for 6 wk, 3 days/wk, whereas half remained without ladders. RT for 6 wk increased lean body mass percentage (P < 0.05), individual muscle masses (gastrocnemius and tibialis anterior) (P < 0.05), and maximum lifting capacity (P < 0.001). The RT group, compared with sedentary controls, had 1) ameliorated spatial learning deficits (P < 0.05), 2) increased dentate gyrus phosphorylation of IGF-1R, protein kinase B, and GSK-3ß proteins (P < 0.05), components of downstream IGF-1 signaling, and 3) increased dentate gyrus synaptic plasticity marker synapsin protein (P < 0.05). Two follow-up experiments (without LPS) characterized dentate gyrus signaling during short-term RT. Twenty-four hours following the third workout in a 1-wk training duration, phosphorylation of ERK1/2 and GSK-3ß proteins, as well as proliferation marker protein, PCNA, were significantly increased (P < 0.05). Similar changes did not occur in a separate group of rats following a single RT workout. Taken together, these data indicate that RT ameliorates LPS-induced MCI after RT, possibly mediated by increased IGF-1 signaling pathway components within the dentate gyrus. NEW & NOTEWORTHY The data suggest that resistance-exercise training restores cognitive deficits induced by lipopolysaccharides and can activate associated IGF-1 signaling in the dentate gyrus. Our data show, for the first time, that as few as three resistance-exercise workouts (spread over 1 wk) can activate IGF-1 downstream signaling and increase proliferation marker PCNA in the dentate gyrus.

Are the metabolic benefits of resistance training in type 2 diabetes linked to improvements in adipose tissue microvascular blood flow?

The microcirculation in adipose tissue is markedly impaired in type 2 diabetes (T2D). Resistance training (RT) often increases muscle mass and promotes a favorable metabolic profile in people with T2D, even in the absence of fat loss. Whether the metabolic benefits of RT in T2D are linked to improvements in adipose tissue microvascular blood flow is unknown. Eighteen sedentary people with T2D (7 women/11 men, 52 ± 7 yr) completed 6 wk of RT. Before and after RT, overnight-fasted participants had blood sampled for clinical chemistries (glucose, insulin, lipids, HbA1c, and proinflammatory markers) and underwent an oral glucose challenge (OGC; 50 g glucose × 2 h) and a DEXA scan to assess body composition. Adipose tissue microvascular blood volume and flow were assessed at rest and 1 h post-OGC using contrast-enhanced ultrasound. RT significantly reduced fasting blood glucose ( P = 0.006), HbA1c ( P = 0.007), 2-h glucose area under the time curve post-OGC ( P = 0.014), and homeostatic model assessment of insulin resistance ( P = 0.005). This was accompanied by a small reduction in total body fat ( P = 0.002), trunk fat ( P = 0.023), and fasting triglyceride levels ( P = 0.029). Lean mass ( P = 0.003), circulating TNF-α ( P = 0.006), and soluble VCAM-1 ( P < 0.001) increased post-RT. There were no significant changes in adipose tissue microvascular blood volume or flow following RT; however those who did have a higher baseline microvascular blood flow post-RT also had lower fasting triglyceride levels ( r = -0.476, P = 0.045). The anthropometric, glycemic, and insulin-sensitizing benefits of 6 wk of RT in people with T2D are not associated with an improvement in adipose tissue microvascular responses; however, there may be an adipose tissue microvascular-linked benefit to fasting triglyceride levels.

Role of Inactivity in Chronic Diseases: Evolutionary Insight and Pathophysiological Mechanisms.

This review proposes that physical inactivity could be considered a behavior selected by evolution for resting, and also selected to be reinforcing in life-threatening situations in which exercise would be dangerous. Underlying the notion are human twin studies and animal selective breeding studies, both of which provide indirect evidence for the existence of genes for physical inactivity. Approximately 86% of the 325 million in the United States (U.S.) population achieve less than the U.S. Government and World Health Organization guidelines for daily physical activity for health. Although underappreciated, physical inactivity is an actual contributing cause to at least 35 unhealthy conditions, including the majority of the 10 leading causes of death in the U.S. First, we introduce nine physical inactivity-related themes. Next, characteristics and models of physical inactivity are presented. Following next are individual examples of phenotypes, organ systems, and diseases that are impacted by physical inactivity, including behavior, central nervous system, cardiorespiratory fitness, metabolism, adipose tissue, skeletal muscle, bone, immunity, digestion, and cancer. Importantly, physical inactivity, itself, often plays an independent role as a direct cause of speeding the losses of cardiovascular and strength fitness, shortening of healthspan, and lowering of the age for the onset of the first chronic disease, which in turn decreases quality of life, increases health care costs, and accelerates mortality risk.

Skeletal Muscle Microvascular-Linked Improvements in Glycemic Control From Resistance Training in Individuals With Type 2 Diabetes.

OBJECTIVE: Insulin increases glucose disposal in part by enhancing microvascular blood flow (MBF) and substrate delivery to myocytes. Insulin's microvascular action is impaired with insulin resistance and type 2 diabetes. Resistance training (RT) improves glycemic control and insulin sensitivity, but whether this improvement is linked to augmented skeletal muscle microvascular responses in type 2 diabetes is unknown. RESEARCH DESIGN AND METHODS: Seventeen (11 male and 6 female; 52 ± 2 years old) sedentary patients with type 2 diabetes underwent 6 weeks of whole-body RT. Before and after RT, participants who fasted overnight had clinical chemistries measured (lipids, glucose, HbA1c, insulin, and advanced glycation end products) and underwent an oral glucose challenge (OGC) (50 g × 2 h). Forearm muscle MBF was assessed by contrast-enhanced ultrasound, skin MBF by laser Doppler flowmetry, and brachial artery flow by Doppler ultrasound at baseline and 60 min post-OGC. A whole-body DEXA scan before and after RT assessed body composition. RESULTS: After RT, muscle MBF response to the OGC increased, while skin microvascular responses were unchanged. These microvascular adaptations were accompanied by improved glycemic control (fasting blood glucose, HbA1c, and glucose area under the curve [AUC] during OGC) and increased lean body mass and reductions in fasting plasma triglyceride, total cholesterol, advanced glycation end products, and total body fat. Changes in muscle MBF response after RT significantly correlated with reductions in fasting blood glucose, HbA1c, and OGC AUC with adjustment for age, sex, % body fat, and % lean mass. CONCLUSIONS: RT improves OGC-stimulated muscle MBF and glycemic control concomitantly, suggesting that MBF plays a role in improved glycemic control from RT.

Training the Next Generation of Latino Health Researchers: A Multilevel, Transdisciplinary, Community-Engaged Approach.

Reducing health disparities is a national public health priority. Latinos represent the largest racial/ethnic minority group in the United States and suffer disproportionately from poor health outcomes, including cardiovascular disease risk. Academic training programs are an opportunity for reducing health disparities, in part by increasing the diversity of the public health workforce and by incorporating training designed to develop a skill set to address health disparities. This article describes the Training and Career Development Program at the UCLA Center for Population Health and Health Disparities: a multilevel, transdisciplinary training program that uses a community-engaged approach to reduce cardiovascular disease risk in two urban Mexican American communities. Results suggest that this program is effective in enhancing the skill sets of traditionally underrepresented students to become health disparities researchers and practitioners.

Rapid Alterations in Perirenal Adipose Tissue Transcriptomic Networks with Cessation of Voluntary Running.

In maturing rats, the growth of abdominal fat is attenuated by voluntary wheel running. After the cessation of running by wheel locking, a rapid increase in adipose tissue growth to a size that is similar to rats that have never run (i.e. catch-up growth) has been previously reported by our lab. In contrast, diet-induced increases in adiposity have a slower onset with relatively delayed transcriptomic responses. The purpose of the present study was to identify molecular pathways associated with the rapid increase in adipose tissue after ending 6 wks of voluntary running at the time of puberty. Age-matched, male Wistar rats were given access to running wheels from 4 to 10 weeks of age. From the 10th to 11th week of age, one group of rats had continued wheel access, while the other group had one week of wheel locking. Perirenal adipose tissue was extracted, RNA sequencing was performed, and bioinformatics analyses were executed using Ingenuity Pathway Analysis (IPA). IPA was chosen to assist in the understanding of complex 'omics data by integrating data into networks and pathways. Wheel locked rats gained significantly more fat mass and significantly increased body fat percentage between weeks 10-11 despite having decreased food intake, as compared to rats with continued wheel access. IPA identified 646 known transcripts differentially expressed (p < 0.05) between continued wheel access and wheel locking. In wheel locked rats, IPA revealed enrichment of transcripts for the following functions: extracellular matrix, macrophage infiltration, immunity, and pro-inflammatory. These findings suggest that increases in visceral adipose tissue that accompanies the cessation of pubertal physical activity are associated with the alteration of multiple pathways, some of which may potentiate the development of pubertal obesity and obesity-associated systemic low-grade inflammation that occurs later in life.

Reduced metabolic disease risk profile by voluntary wheel running accompanying juvenile Western diet in rats bred for high and low voluntary exercise.

Metabolic disease risk is influenced by genetics and modifiable factors, such as physical activity and diet. Beginning at 6 weeks of age, rats selectively bred for high (HVR) versus low voluntary running distance (LVR) behaviors were housed in a complex design with or without voluntary running wheels being fed either a standard or Western (WD, 42% kcal from fat and added sucrose) diet for 8 weeks. Upon intervention completion, percent body fat, leptin, insulin, and mediobasal hypothalamic mRNAs related to appetite control were assessed. Wheel access led to differences in body weight, food intake, and serum leptin and insulin. Intriguingly, percent body fat, leptin, and insulin did not differ between HVR and LVR lines in response to the two levels of voluntary running, regardless of diet, after the 8 wk. experiment despite HVR eating more calories than LVR regardless of diet and voluntarily running 5-7 times further in wheels than LVR. In response to WD, we observed increases in Cart and Lepr mediobasal hypothalamic mRNA in HVR, but no differences in LVR. Npy mRNA was intrinsically greater in LVR than HVR, while wheel access led to greater Pomc and Cart mRNA in LVR versus HVR. These data suggest that despite greater consumption of WD, HVR animals respond similarly to WD as LVR as a result, in part, of their increased wheel running behavior. Furthermore, high physical activity in HVR may offset the deleterious effects of a WD on adiposity despite greater energy intake in this group.

Effects of Exercise Training on Cardiorespiratory Fitness and Biomarkers of Cardiometabolic Health: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

BACKGROUND: Guidelines recommend exercise for cardiovascular health, although evidence from trials linking exercise to cardiovascular health through intermediate biomarkers remains inconsistent. We performed a meta-analysis of randomized controlled trials to quantify the impact of exercise on cardiorespiratory fitness and a variety of conventional and novel cardiometabolic biomarkers in adults without cardiovascular disease. METHODS AND RESULTS: Two researchers selected 160 randomized controlled trials (7487 participants) based on literature searches of Medline, Embase, and Cochrane Central (January 1965 to March 2014). Data were extracted using a standardized protocol. A random-effects meta-analysis and systematic review was conducted to evaluate the effects of exercise interventions on cardiorespiratory fitness and circulating biomarkers. Exercise significantly raised absolute and relative cardiorespiratory fitness. Lipid profiles were improved in exercise groups, with lower levels of triglycerides and higher levels of high-density lipoprotein cholesterol and apolipoprotein A1. Lower levels of fasting insulin, homeostatic model assessment-insulin resistance, and glycosylated hemoglobin A1c were found in exercise groups. Compared with controls, exercise groups had higher levels of interleukin-18 and lower levels of leptin, fibrinogen, and angiotensin II. In addition, we found that the exercise effects were modified by age, sex, and health status such that people aged <50 years, men, and people with type 2 diabetes, hypertension, dyslipidemia, or metabolic syndrome appeared to benefit more. CONCLUSIONS: This meta-analysis showed that exercise significantly improved cardiorespiratory fitness and some cardiometabolic biomarkers. The effects of exercise were modified by age, sex, and health status. Findings from this study have significant implications for future design of targeted lifestyle interventions.

Effect of combined aerobic and resistance training versus aerobic training on arterial stiffness.

BACKGROUND: While aerobic exercise training may decrease arterial stiffness, the impact of combined aerobic and resistance training is unclear. Therefore, the aim of this study was to systematically review and quantify the effect of combined aerobic and resistance training on arterial stiffness, as determined by arterial pulse wave velocity (PWV), and compare it with aerobic training. METHODS: MEDLINE, EMBASE and Web of Science were searched through November 2013 for randomized controlled trials evaluating the effect of aerobic or combined aerobic and resistance training on PWV. A meta-analysis was performed to determine the standardized mean difference (SMD) in PWV between exercise and control groups. Subgroup analyses were used to study potential moderating factors. RESULTS: Twenty-one randomized controlled trials comparing exercise and control groups (overall n=752), met the inclusion criteria. After data pooling, PWV was decreased in aerobic trained groups compared with controls (10 trials, SMD=-0.52, 95% CI= -0.76, -0.27; P<0.0001) but did not reach statistical significance in combined trained groups compared with controls (11 trials, SMD=-0.23, 95% CI=-0.50, 0.04; P=0.10). The effect in aerobic trained groups did not differ compared with combined trained groups (P=0.12). In addition, aerobic training resulted in significantly lower SMD in PWV compared with combined training in interventions including a higher volume of aerobic training or assessing carotid-femoral PWV. CONCLUSIONS: These data suggest that combined aerobic and resistance training interventions may have reduced beneficial effects on arterial stiffness compared with control interventions, but do not appear to differ significantly with aerobic training alone.

Strength fitness and body weight status on markers of cardiometabolic health.

INTRODUCTION: Recent evidence suggests that resistance training (RT) may reduce metabolic and cardiovascular disease risk. We investigated whether overweight/class I obese individuals by BMI classification with high strength fitness exhibit cardiovascular/metabolic phenotypes similar to those overweight/obese and untrained or those normal-weight with high strength fitness. METHODS: A total of 90 young males were categorized into three groups: overweight untrained (OU, n = 30, BMI > 27 kg·m⁻²), overweight trained (OT, n = 30, BMI > 27 kg·m⁻², RT ≥ 4 d·wk⁻¹), and normal-weight trained (NT, n = 30, BMI < 25 kg·m⁻², RT ≥ 4 d·wk⁻¹). Participants were assessed for strength, body composition, central/peripheral blood pressures, arterial stiffness, and markers of cardiovascular and metabolic health. RESULTS: Body weight was similar in OT and OU and greater than NT (P < 0.00001), and fat mass was different in all groups (P < 0.001). Compared to OU, NT and OT groups exhibited higher relative strength (NT = 46.7%, OT = 44.4%, P < 0.00001), subendocardial viability ratio (NT = 21.0%, P < 0.001; OT = 17.0%, P < 0.01), and lower brachial/central blood pressures (NT P < 0.001; OT P ≤ 0.05); augmentation index and pulse-wave velocity were lower only in OT (P < 0.05). Total cholesterol, low-density lipoprotein (NT P < 0.01, OT P < 0.05), triglycerides (NT = -50.4%, OT = -41.8%, P < 0.001), oxidized LDL (NT = -39.8%, OT = -31.8%, P < 0.001), and CRP (NT = -63.7%, OT = -67.4%, P < 0.01) levels were lower and high-density lipoprotein (NT = 26.9%, OT = 21.4%, P < 0.001) levels were higher in NT and OT compared to OU. NT and OT also exhibited lower amylin (NT = -55.8%, OT = -40.8%) and leptin (NT = -84.6%, OT = -59.4%) and higher adiponectin (NT = 87.5%, P < 0.001; OT = 78.1%, P < 0.01) and sex hormone-binding globulin (NT = 124.4%, OT = 92.3%, P < 0.001). Despite greater total and trunk fat in OT compared with NT, other than glucose and insulin, which were lower in NT than in both OT and OU (OT P < 0.01, OU P < 0.001), OT did not exhibit any impaired biomarker/phenotype compared to NT. CONCLUSIONS: These findings provide evidence that overweight/class I obese individuals with high strength fitness exhibit metabolic/cardiovascular risk profiles similar to normal-weight, fit individuals rather than overweight/class I obese unfit individuals. Strength training may be important to metabolic and cardiovascular health.

A high throughput biochemical fluorometric method for measuring lipid peroxidation in HDL.

Current cell-based assays for determining the functional properties of high-density lipoproteins (HDL) have limitations. We report here the development of a new, robust fluorometric cell-free biochemical assay that measures HDL lipid peroxidation (HDLox) based on the oxidation of the fluorochrome Amplex Red. HDLox correlated with previously validated cell-based (r = 0.47, p<0.001) and cell-free assays (r = 0.46, p<0.001). HDLox distinguished dysfunctional HDL in established animal models of atherosclerosis and Human Immunodeficiency Virus (HIV) patients. Using an immunoaffinity method for capturing HDL, we demonstrate the utility of this novel assay for measuring HDLox in a high throughput format. Furthermore, HDLox correlated significantly with measures of cardiovascular diseases including carotid intima media thickness (r = 0.35, p<0.01) and subendocardial viability ratio (r = -0.21, p = 0.05) and physiological parameters such as metabolic and anthropometric parameters (p<0.05). In conclusion, we report the development of a new fluorometric method that offers a reproducible and rapid means for determining HDL function/quality that is suitable for high throughput implementation.

A pilot validation of multi-echo based echo-planar correlated spectroscopic imaging in human calf muscles.

A current limitation of MR spectroscopic imaging of multiple skeletal muscles is prolonged scan duration. A significant reduction in the total scan duration using the echo-planar correlated spectroscopic imaging (EP-COSI) sequence was accomplished using two bipolar readout trains with different phase-encoded echoes for one of two spatial dimensions within a single repetition time (TR). The second bipolar readout was used for spatially encoding the outer k-space, whereas the first readout was used for the central k-space only. The performance of this novel sequence, called multi-echo based echo-planar correlated spectroscopic imaging (ME-EPCOSI), was demonstrated by localizing specific key features in calf muscles and bone marrow of 11 healthy volunteers and five subjects with type 2 diabetes (T2D). A 3 T MRI-MRS scanner equipped with a transmit-receive extremity coil was used. Localization of the ME-EPCOSI sequence was in good agreement with the earlier single-readout based EP-COSI sequence and the required scan time was reduced by a factor of two. In agreement with an earlier report using single-voxel based 2D MRS, significantly increased unsaturated pools of intramyocellular lipid (IMCL) and extramyocellular lipid (EMCL) and decreased IMCL and EMCL unsaturation indices (UIs) were observed in the soleus and tibialis anterior muscle regions of subjects with T2D compared with healthy controls. In addition, significantly decreased choline content was observed in the soleus of T2D subjects compared with healthy controls. Multi-voxel characterization of IMCL and EMCL ratios and UI in the calf muscle may be useful for the non-invasive assessment of altered lipid metabolism in the pathophysiology of T2D.

Impact of diet and exercise on lipid management in the modern era.

Unfortunately, many patients as well as the medical community, continue to rely on coronary revascularization procedures and cardioprotective medications as a first-line strategy to stabilize or favorably modify established risk factors and the course of coronary artery disease. However, these therapies do not address the root of the problem, that is, the most proximal risk factors for heart disease, including unhealthy dietary practices, physical inactivity, and cigarette smoking. We argue that more emphasis must be placed on novel approaches to embrace current primary and secondary prevention guidelines, which requires attacking conventional risk factors and their underlying environmental causes. The impact of lifestyle on the risk of cardiovascular disease has been well established in clinical trials, but these results are often overlooked and underemphasized. Considerable data also strongly support the role of lifestyle intervention to improve glucose and insulin homeostasis, as well as physical inactivity and/or low aerobic fitness. Accordingly, intensive diet and exercise interventions can be highly effective in facilitating coronary risk reduction, complementing and enhancing medications, and in some instances, even outperforming drug therapy.

Effect of aerobic exercise training on arterial stiffness in obese populations : a systematic review and meta-analysis.

BACKGROUND AND OBJECTIVE: Controversy exists as to whether aerobic exercise training decreases arterial stiffness in obese subjects. The aim of this study was to systematically review and quantify the effect of aerobic exercise training on arterial stiffness in obese populations. METHODS: MEDLINE, Cochrane, Scopus, and Web of Science were searched up until May 2013 for trials assessing the effect of aerobic training interventions lasting 8 weeks or more on arterial stiffness in obese populations (body mass index ≥30 kg/m(2)). Standardized mean difference (SMD) in arterial stiffness parameters (augmentation index, ß-stiffness, distensibility, pulse wave velocity, arterial waveforms) was calculated using a random-effects model. Subgroup and meta-regression analyses were used to study potential moderating factors. RESULTS: Eight trials, comprising a total of 235 subjects with an age range of 49-70 years, met the inclusion criteria. Arterial stiffness was not significantly reduced by aerobic training (SMD -0.17; 95 % confidence interval (CI) -0.39, 0.06, P = 0.14). Similarly, post-intervention arterial stiffness was similar between the aerobic-trained and control obese groups (SMD 0.02; 95 % CI -0.28, 0.32, P = 0.88). Neither heterogeneity nor publication bias were detected in these analyses. In subgroup analyses, arterial stiffness was significantly reduced in aerobic-trained subgroups having below median values in post- minus pre-intervention systolic blood pressure (SBP) (P < 0.01), exercise intensity rating score (P < 0.01), and methodological quality score (P < 0.01). Equivalent results were obtained in meta-regression analyses. CONCLUSION: Based on current published trials, arterial stiffness is generally not reduced in middle-aged and older obese populations in response to aerobic training. However, in studies using low-intensity aerobic training and yielding a decrease in SBP, arterial stiffness may decrease. Long-term studies are needed to assess the prognostic value of these findings.

Designing a robust activity recognition framework for health and exergaming using wearable sensors.

Detecting human activity independent of intensity is essential in many applications, primarily in calculating metabolic equivalent rates and extracting human context awareness. Many classifiers that train on an activity at a subset of intensity levels fail to recognize the same activity at other intensity levels. This demonstrates weakness in the underlying classification method. Training a classifier for an activity at every intensity level is also not practical. In this paper, we tackle a novel intensity-independent activity recognition problem where the class labels exhibit large variability, the data are of high dimensionality, and clustering algorithms are necessary. We propose a new robust stochastic approximation framework for enhanced classification of such data. Experiments are reported using two clustering techniques, K-Means and Gaussian Mixture Models. The stochastic approximation algorithm consistently outperforms other well-known classification schemes which validate the use of our proposed clustered data representation. We verify the motivation of our framework in two applications that benefit from intensity-independent activity recognition. The first application shows how our framework can be used to enhance energy expenditure calculations. The second application is a novel exergaming environment aimed at using games to reward physical activity performed throughout the day, to encourage a healthy lifestyle.