Introduction: Walking interventions focused on increasing step counts are typically associated wi... more Introduction: Walking interventions focused on increasing step counts are typically associated with salutary effects on glycemia, fasting insulin, insulin resistance and blood lipids which may be in turn associated with improvements in cardiorespiratory fitness (peak oxygen uptake [[Unable to Display Character: –]] VO 2peak ) and vascular stiffness. We hypothesized that a novel 4-month, behavioral economics-based walking intervention would have favorable effects on glucose homeostasis and blood lipids and that these in turn would be related to VO 2peak and vascular stiffness (carotid femoral pulse wave velocity [[Unable to Display Character: –]] cfPWV). Methods: We carried out secondary analyses on a subsample of sedentary, overweight/obese adults who participated in a 4-month, 2x2, randomized-controlled walking intervention examining the effects of goal setting (static v. adaptive goals) and rewards (immediate v. delayed) on steps/day (N=96). Fasting blood samples (n=58) were colle...
Introduction: Improvements in physical activity (PA) are strongly associated with increases in va... more Introduction: Improvements in physical activity (PA) are strongly associated with increases in vascular health among inactive populations. The Walking Intervention Through Texting (WalkIT) trial, a 4-month 2x2 factorial randomized controlled trial, examined impacts of goal setting (adaptive vs. static) and financial reward type (small immediate vs. larger delayed) on PA (walking steps/day) in 96 sedentary, overweight and obese adults. An exploratory aim of the trial was to investigate treatment effects on novel biomarkers associated with central arterial stiffness (carotid femoral pulse wave velocity - cfPWV). Hypothesis: We hypothesized that adaptive goal and immediate reward groups would show greater pre- to post-trial improvements in biomarkers and cfPWV than static goal and delayed reward groups. Methods: Changes in biomarkers were examined for a randomly drawn subsample of 36 participants (n=9 per group; age = 42.3±10.7). Fasting blood plasma samples and cfPWV measurements were...
Introduction: Behavioral economics-based interventions for increasing steps/day may improve cardi... more Introduction: Behavioral economics-based interventions for increasing steps/day may improve cardiorespiratory fitness (CRF; Peak O2 uptake - VO2peak), central/aortic blood pressure, and vascular stiffness. The purpose of this study was to examine the effects of adaptive (Ad) physical activity (PA) goals (daily step goals based on prior 10-day window and a percentile algorithm) vs. static (St) PA goals (10,000 steps/day) combined with either immediate (Im) financial micro-incentives or delayed (De) incentives (Groups: Ad+Im; Ad+De; St+Im; St+De) on VO2peak, blood pressure and vascular stiffness. We hypothesized that participants randomized to adaptive goals with immediate reinforcement (Ad+Im) would have greater improvements in cardiovascular health measures than participants assigned to static goals and/or delayed reinforcement conditions (active controls). Methods: Inactive adults (Age = 41.8 ± 6.7yrs; BMI = 34.5 ± 6 kg/m2) were randomized to an adaptive/static goal intervention wi...
Maximal oxygen uptake (VO2max) declines with advancing age and is a predictor of morbidity and mo... more Maximal oxygen uptake (VO2max) declines with advancing age and is a predictor of morbidity and mortality risk. The purpose here was to assess the utility of constant load tests performed either above or below peak work rate obtained from a graded exercise test for verification of VO2max in older adults. Twenty‐two healthy older adults (9M, 13F, 67 ± 6 years, BMI: 26.3 ± 5.1 kg·m−2) participated in the study. Participants were asked to complete two experimental trials in a randomized, counterbalanced cross‐over design. Both trials (cycle ergometer) consisted of (1) an identical graded exercise test (ramp) and (2) a constant load test at either 85% (CL85; n = 22) or 110% (CL110; n = 20) of the peak work rate achieved during the associated ramp (performed 10‐min post ramp). No significant differences were observed for peak VO2 (L·min−1) between CL85 (1.86 ± 0.72; p = 0.679) or CL110 (1.79 ± 0.73; p = 0.200) and the associated ramp (Ramp85, 1.85 ± 0.73; Ramp110, 1.85 ± 0.57). Using the study participant's mean coefficient of variation in peak VO2 between the two identical ramp tests (2.9%) to compare individual differences between constant load tests and the associated ramp revealed 19/22 (86%) of participants achieved a peak VO2 during CL85 that was similar or higher versus the ramp, while only 13/20 (65%) of participants achieved a peak VO2 during CL110 that was similar or higher versus the ramp. These data indicate that if a verification of VO2max is warranted when testing older adults, a constant load effort at 85% of ramp peak power may be more likely to verify VO2max as compared to an effort at 110% of ramp peak power.
Summary We propose a weight-neutral strategy for obesity treatment on the following grounds: (1) ... more Summary We propose a weight-neutral strategy for obesity treatment on the following grounds: (1) the mortality risk associated with obesity is largely attenuated or eliminated by moderate-to-high levels of cardiorespiratory fitness (CRF) or physical activity (PA), (2) most cardiometabolic risk markers associated with obesity can be improved with exercise training independent of weight loss and by a magnitude similar to that observed with weight-loss programs, (3) weight loss, even if intentional, is not consistently associated with lower mortality risk, (4) increases in CRF or PA are consistently associated with greater reductions in mortality risk than is intentional weight loss, and (5) weight cycling is associated with numerous adverse health outcomes including increased mortality. Adherence to PA may improve if health care professionals consider PA and CRF as essential vital signs and consistently emphasize to their patients the myriad benefits of PA and CRF in the absence of weight loss.
Journal of Cardiopulmonary Rehabilitation and Prevention, 2019
Heart failure with preserved ejection fraction (HFpEF) is the fastest growing form of heart failu... more Heart failure with preserved ejection fraction (HFpEF) is the fastest growing form of heart failure in the United States. The cardinal feature of HFpEF is reduced exercise tolerance (peak oxygen uptake, JOURNAL/jcprh/04.03/01273116-202001000-00003/3FSM1/v/2023-09-11T232142Z/r/image-gif o 2peak) secondary to impaired cardiac, vascular, and skeletal muscle function. There are currently no evidence-based drug therapies to improve clinical outcomes in patients with HFpEF. In contrast, exercise training is a proven effective intervention for improving JOURNAL/jcprh/04.03/01273116-202001000-00003/3FSM1/v/2023-09-11T232142Z/r/image-gif o 2peak, aerobic endurance, and quality of life in HFpEF patients. This brief review discusses the pathophysiology of exercise intolerance and the role of exercise training to improve JOURNAL/jcprh/04.03/01273116-202001000-00003/3FSM1/v/2023-09-11T232142Z/r/image-gif o 2peak in clinically stable HFpEF patients. It also discusses the mechanisms responsible fo...
The consumption of fiber-rich foods may negate the deleterious effects of high-fat meals on postp... more The consumption of fiber-rich foods may negate the deleterious effects of high-fat meals on postprandial triglyceridemia and endothelial function. Despite supportive data in adults, little is known about the effects of high-fat and high-fiber foods on cardiovascular health parameters in pediatric populations. In this crossover trial, male and female adolescents (n = 10; 14.1 + 2.6 years; range 10–17 years) consumed (1) low-fat, low-fiber, (2) low-fat, high-fiber, (3) high-fat, low-fiber, and (4) high-fat, high-fiber breakfast meals in randomized order, each following an overnight fast. Baseline and 4 h post-meal blood was obtained for determination of glucose, insulin and triglyceride concentrations. Endothelial function was assessed via brachial artery flow-mediated dilation (FMD). Postprandial FMD was not significantly changed after any meal. However, regression analyses revealed a significant inverse relationship between the change in 4 h triglyceride concentration and change in ...
Introduction: Walking interventions focused on increasing step counts are typically associated wi... more Introduction: Walking interventions focused on increasing step counts are typically associated with salutary effects on glycemia, fasting insulin, insulin resistance and blood lipids which may be in turn associated with improvements in cardiorespiratory fitness (peak oxygen uptake [[Unable to Display Character: –]] VO 2peak ) and vascular stiffness. We hypothesized that a novel 4-month, behavioral economics-based walking intervention would have favorable effects on glucose homeostasis and blood lipids and that these in turn would be related to VO 2peak and vascular stiffness (carotid femoral pulse wave velocity [[Unable to Display Character: –]] cfPWV). Methods: We carried out secondary analyses on a subsample of sedentary, overweight/obese adults who participated in a 4-month, 2x2, randomized-controlled walking intervention examining the effects of goal setting (static v. adaptive goals) and rewards (immediate v. delayed) on steps/day (N=96). Fasting blood samples (n=58) were colle...
Introduction: Improvements in physical activity (PA) are strongly associated with increases in va... more Introduction: Improvements in physical activity (PA) are strongly associated with increases in vascular health among inactive populations. The Walking Intervention Through Texting (WalkIT) trial, a 4-month 2x2 factorial randomized controlled trial, examined impacts of goal setting (adaptive vs. static) and financial reward type (small immediate vs. larger delayed) on PA (walking steps/day) in 96 sedentary, overweight and obese adults. An exploratory aim of the trial was to investigate treatment effects on novel biomarkers associated with central arterial stiffness (carotid femoral pulse wave velocity - cfPWV). Hypothesis: We hypothesized that adaptive goal and immediate reward groups would show greater pre- to post-trial improvements in biomarkers and cfPWV than static goal and delayed reward groups. Methods: Changes in biomarkers were examined for a randomly drawn subsample of 36 participants (n=9 per group; age = 42.3±10.7). Fasting blood plasma samples and cfPWV measurements were...
Introduction: Behavioral economics-based interventions for increasing steps/day may improve cardi... more Introduction: Behavioral economics-based interventions for increasing steps/day may improve cardiorespiratory fitness (CRF; Peak O2 uptake - VO2peak), central/aortic blood pressure, and vascular stiffness. The purpose of this study was to examine the effects of adaptive (Ad) physical activity (PA) goals (daily step goals based on prior 10-day window and a percentile algorithm) vs. static (St) PA goals (10,000 steps/day) combined with either immediate (Im) financial micro-incentives or delayed (De) incentives (Groups: Ad+Im; Ad+De; St+Im; St+De) on VO2peak, blood pressure and vascular stiffness. We hypothesized that participants randomized to adaptive goals with immediate reinforcement (Ad+Im) would have greater improvements in cardiovascular health measures than participants assigned to static goals and/or delayed reinforcement conditions (active controls). Methods: Inactive adults (Age = 41.8 ± 6.7yrs; BMI = 34.5 ± 6 kg/m2) were randomized to an adaptive/static goal intervention wi...
Maximal oxygen uptake (VO2max) declines with advancing age and is a predictor of morbidity and mo... more Maximal oxygen uptake (VO2max) declines with advancing age and is a predictor of morbidity and mortality risk. The purpose here was to assess the utility of constant load tests performed either above or below peak work rate obtained from a graded exercise test for verification of VO2max in older adults. Twenty‐two healthy older adults (9M, 13F, 67 ± 6 years, BMI: 26.3 ± 5.1 kg·m−2) participated in the study. Participants were asked to complete two experimental trials in a randomized, counterbalanced cross‐over design. Both trials (cycle ergometer) consisted of (1) an identical graded exercise test (ramp) and (2) a constant load test at either 85% (CL85; n = 22) or 110% (CL110; n = 20) of the peak work rate achieved during the associated ramp (performed 10‐min post ramp). No significant differences were observed for peak VO2 (L·min−1) between CL85 (1.86 ± 0.72; p = 0.679) or CL110 (1.79 ± 0.73; p = 0.200) and the associated ramp (Ramp85, 1.85 ± 0.73; Ramp110, 1.85 ± 0.57). Using the study participant's mean coefficient of variation in peak VO2 between the two identical ramp tests (2.9%) to compare individual differences between constant load tests and the associated ramp revealed 19/22 (86%) of participants achieved a peak VO2 during CL85 that was similar or higher versus the ramp, while only 13/20 (65%) of participants achieved a peak VO2 during CL110 that was similar or higher versus the ramp. These data indicate that if a verification of VO2max is warranted when testing older adults, a constant load effort at 85% of ramp peak power may be more likely to verify VO2max as compared to an effort at 110% of ramp peak power.
Summary We propose a weight-neutral strategy for obesity treatment on the following grounds: (1) ... more Summary We propose a weight-neutral strategy for obesity treatment on the following grounds: (1) the mortality risk associated with obesity is largely attenuated or eliminated by moderate-to-high levels of cardiorespiratory fitness (CRF) or physical activity (PA), (2) most cardiometabolic risk markers associated with obesity can be improved with exercise training independent of weight loss and by a magnitude similar to that observed with weight-loss programs, (3) weight loss, even if intentional, is not consistently associated with lower mortality risk, (4) increases in CRF or PA are consistently associated with greater reductions in mortality risk than is intentional weight loss, and (5) weight cycling is associated with numerous adverse health outcomes including increased mortality. Adherence to PA may improve if health care professionals consider PA and CRF as essential vital signs and consistently emphasize to their patients the myriad benefits of PA and CRF in the absence of weight loss.
Journal of Cardiopulmonary Rehabilitation and Prevention, 2019
Heart failure with preserved ejection fraction (HFpEF) is the fastest growing form of heart failu... more Heart failure with preserved ejection fraction (HFpEF) is the fastest growing form of heart failure in the United States. The cardinal feature of HFpEF is reduced exercise tolerance (peak oxygen uptake, JOURNAL/jcprh/04.03/01273116-202001000-00003/3FSM1/v/2023-09-11T232142Z/r/image-gif o 2peak) secondary to impaired cardiac, vascular, and skeletal muscle function. There are currently no evidence-based drug therapies to improve clinical outcomes in patients with HFpEF. In contrast, exercise training is a proven effective intervention for improving JOURNAL/jcprh/04.03/01273116-202001000-00003/3FSM1/v/2023-09-11T232142Z/r/image-gif o 2peak, aerobic endurance, and quality of life in HFpEF patients. This brief review discusses the pathophysiology of exercise intolerance and the role of exercise training to improve JOURNAL/jcprh/04.03/01273116-202001000-00003/3FSM1/v/2023-09-11T232142Z/r/image-gif o 2peak in clinically stable HFpEF patients. It also discusses the mechanisms responsible fo...
The consumption of fiber-rich foods may negate the deleterious effects of high-fat meals on postp... more The consumption of fiber-rich foods may negate the deleterious effects of high-fat meals on postprandial triglyceridemia and endothelial function. Despite supportive data in adults, little is known about the effects of high-fat and high-fiber foods on cardiovascular health parameters in pediatric populations. In this crossover trial, male and female adolescents (n = 10; 14.1 + 2.6 years; range 10–17 years) consumed (1) low-fat, low-fiber, (2) low-fat, high-fiber, (3) high-fat, low-fiber, and (4) high-fat, high-fiber breakfast meals in randomized order, each following an overnight fast. Baseline and 4 h post-meal blood was obtained for determination of glucose, insulin and triglyceride concentrations. Endothelial function was assessed via brachial artery flow-mediated dilation (FMD). Postprandial FMD was not significantly changed after any meal. However, regression analyses revealed a significant inverse relationship between the change in 4 h triglyceride concentration and change in ...
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