Resistance Exercise Training in Individuals With and Without Cardiovascular Disease: 2023 Update: A Scientific Statement From the American Heart Association

Resistance training not only can improve or maintain muscle mass and strength, but also has favorable physiological and clinical effects on cardiovascular disease and risk factors. This scientific statement is an update of the previous (2007) American Heart Association scientific statement regarding resistance training and cardiovascular disease. Since 2007, accumulating evidence suggests resistance training is a safe and effective approach for improving cardiovascular health in adults with and without cardiovascular disease. This scientific statement summarizes the benefits of resistance training alone or in combination with aerobic training for improving traditional and nontraditional cardiovascular disease risk factors. We also address the utility of resistance training for promoting cardiovascular health in varied healthy and clinical populations. Because less than one-third of US adults report participating in the recommended 2 days per week of resistance training activities, this scientific statement provides practical strategies for the promotion and prescription of resistance training.

The effect of exercise training level on arterial stiffness after clinically significant weight loss

Arterial stiffness is improved by weight loss. However, no data exist on the impact of aerobic exercise levels on arterial stiffness during weight maintenance. Adults who were  overweight or with obesity (N = 39) participated in a 10-week weight loss program. Participants who achieved ≥7% weight loss were randomized to aerobic training at the minimum physical activity guidelines (PA-REC, 550 MET min/week) or weight maintenance guidelines (WM-REC, 970 MET min/week) for 18 additional weeks. Arterial stiffness (carotid-to-femoral pulse wave velocity [cfPWV], augmentation index normalized for 75 beats/min [AIX75]) and blood pressure [aortic and brachial]) were assessed at baseline, the end of the weight loss phase (week 10), and follow-up (week 28). There was a reduction in cfPWV in participants who met the weight loss goal (-0.34 m/s, p = .02) and approached significance for the entire sample (p = .051). Similarly, there were reductions in AIX75, brachial blood pressure, and aortic blood pressure (p < .05) in the full sample. In the weight maintenance phase, no differences were observed between the PA-REC and the WM-REC groups for change in arterial stiffness or blood pressure (p > .05). However, changes in cfPWV were independently associated with changes in LDL (r2 : 0.45, p = .004) and exercise intensity (r2 : 0.17, p = .033). Aerobic exercise level at the minimum physical activity guidelines or weight maintenance guidelines does not affect the change in PWV or the change in cfPWV after clinically significant weight loss. However, interventions which limit increases in LDL cholesterol and promote high-intensity aerobic exercise may prevent increases in stiffness during weight maintenance.

Effects of weight loss and weight loss maintenance on cardiac autonomic function in obesity: a randomized controlled trial

NOVELTY

Caloric restriction and exercise exert significant improvements in cardiac autonomic function as measured by HRV in overweight and obesity. Aerobic exercise training, within recommended guidelines coupled with weight loss maintenance, retains cardiac autonomic function benefits from weight loss in previously obese individuals.

Increasing Equity of Physical Activity Promotion for Optimal Cardiovascular Health in Adults: A Scientific Statement From the American Heart Association

Fewer than 1 in 4 adults achieves the recommended amount of physical activity, with lower activity levels reported among some groups. Addressing low levels of physical activity among underresourced groups provides a modifiable target with the potential to improve equity in cardiovascular health. This article (1) examines physical activity levels across strata of cardiovascular disease risk factors, individual level characteristics, and environmental factors; (2) reviews strategies for increasing physical activity in groups who are underresourced or at risk for poor cardiovascular health; and (3) provides practical suggestions for physical activity promotion to increase equity of risk reduction and to improve cardiovascular health. Physical activity levels are lower among those with elevated cardiovascular disease risk factors, among certain groups (eg, older age, female, Black race, lower socioeconomic status), and in some environments (eg, rural). There are strategies for physical activity promotion that can specifically support underresourced groups such as engaging the target community in designing and implementing interventions, developing culturally appropriate study materials, identifying culturally tailored physical activity options and leaders, building social support, and developing materials for those with low literacy. Although addressing low physical activity levels will not address the underlying structural inequities that deserve attention, promoting physical activity among adults, especially those with both low physical activity levels and poor cardiovascular health, is a promising and underused strategy to reduce cardiovascular health inequalities.

Abstract P145: The Effect of Exercise Level on Weight Maintenance and Cardiometabolic Risk Factors After Clinically Significant Weight Loss: Results From the Prevail-p Study

Introduction: Clinically significant weight loss is associated with health benefits for overweight and obese adults. Participation in adequate amounts of physical activity is critical for weight maintenance. However, few studies in the literature have evaluated the amount of physical activity needed to promote weight maintenance in a supervised exercise training study with corresponding data on cardiovascular risk factors.

Methods: Overweight and obese adults (N=39) completed a 10-week OPTIFAST ® weight loss program with supervised aerobic exercise training with the goal of achieving clinically significant weight loss (≥7%). Participants who met the weight loss goal were randomized to levels of aerobic training consistent with physical activity recommendations (PA-REC) (~550 MET minutes per week) or weight maintenance recommendations (WM-REC) (~970 MET minutes per week) for 18 additional weeks. Weight, body composition, and blood measures (e.g., fasting glucose, insulin, and lipids) were measured at baseline, after weight loss (10 weeks), and at follow-up (28 weeks).

Results: Thirty-three of the 39 participants achieved clinically significant weight loss (~85%). There were reductions in weight (-8.8 kg), body fat (-2.1%), visceral fat (-120.4 g), along with other health indicators (systolic blood pressure [-6.8 mmHg], diastolic blood pressure [-5.9 mmHg], HOMA-IR [-2.4] and lipids) after the weight loss phase (all p’s< 0.05). Full data for the weight maintenance phase were available in 21 participants due to the COVID pandemic (PA-REC: 12, WM-REC:9). Larger improvements in cardiorespiratory fitness (as assessed by estimated METs [1.7 vs. 0 METs, p=0.01] and relative VO 2 peak [2.3 vs.0.5 ml/kg/min, p=0.04]) were observed in the WM-REC group compared to the PA-REC group, while changes in waist circumference (-2.4 vs. 0.5 cm, p=0.06), visceral fat (-45.7 vs. 8.2 g, p=0.06), and absolute VO 2 (0.1 vs. 0.2 L/min, p=0.09) approached significance. No significant changes were observed between groups for changes in weight, blood pressure, glucose metabolism, or lipid parameters during the maintenance phase (all ps>0.05).

Discussion: Clinically significant weight loss combined with aerobic exercise resulted in improvements in cardiometabolic parameters. Exercise at levels associated with the weight maintenance guidelines resulted in greater improvements in cardiorespiratory fitness and may have the potential to improve measures of central adiposity to a greater extent than the minimum physical activity recommendations following weight loss. Future studies should evaluate the impact of different levels of aerobic exercise after clinically significant weight loss in long term interventions.

Minor Improvement in Activity and Participation and Decline in Physical Activity Motivation After Cardiac Rehabilitation Discharge

PURPOSE

To investigate the changes in activities and participation, and mental and physical functions for 9 mo after cardiac rehabilitation (CR) among adults with chronic cardiac conditions.

METHODS

Twenty-five adults with chronic cardiac conditions scheduled for discharge from CR were assessed at four different times: within 2-wk window of CR discharge date, 1 mo, 3 mo, and 9 mo after CR discharge. Nine assessments according to the International Classification of Functioning, Disability and Health were used to track the changes post-CR.

RESULTS

Participants showed significant changes in the Cognitive Instrumental Activities of Daily Living adequacy of Performance Assessment of Self-Care Skills-Clinic (F = 8.10, P = .017) and improvements in the applied cognitive domain of the Activity Measure for Post-Acute Care Outpatient Short Form (F = 4.493, P = .016). Participants also showed significant decline in the CogState Detection test (F = 3.307, P = .045), the Physical Activity and Leisure Motivation Scale (PALMS) (F = 4.749, P = .005), and the affiliation subscale of the PALMS (F = 5.316, P = .002), and improvements in the 6-min walk test (F = 9.000, P = .011). Lastly, participants showed depressive symptoms for 3 mo post-CR. No other significant changes were detected among other outcome measures.

CONCLUSIONS

Adults with chronic cardiac conditions discharged from site-based CR maintained their activity and participation level following discharge with little improvement. They also showed depressive symptoms and decreased motivation for physical activity post-CR.

Comparison of Activity and Participation, and Mental and Physical Functions of Immediate Post-Acute and Distant Post-Acute Adults with Chronic Cardiac Conditions

This study compared activity participation, and mental and physical functions of two different groups of adults with chronic cardiac conditions. Eleven participants were assessed at the immediate post-acute stage and 26 participants were at the distant post-acute stage. Participants at distant post-acute were significantly more physically active (p < .001), more activity-limited in cognition-related activities (p = .035) and reported more depressive symptoms than immediate post-acute (p = .046). No significant difference in participation level was found. More attention to functional cognition and depressive symptoms at immediate post-acute and individualized approaches to remove participation barriers in complex activities at distant post-acute are likely needed for adults with chronic cardiac conditions.

The Effect of Aerobic Training and Increasing Nonexercise Physical Activity on Cardiometabolic Risk Factors

PURPOSE

Epidemiological studies suggest that sedentary behavior is an independent risk factor for cardiovascular mortality independent of meeting physical activity guidelines. However, limited evidence of this relationship is available from prospective interventions. The purpose of the present study is to evaluate the combined effect of aerobic training and increasing non-exercise physical activity on body composition and cardiometabolic risk factors.

METHODS

Obese adults (N=45) were randomized to 6-months of aerobic training (AERO), aerobic training and increasing non-exercise physical activity (~3,000 steps above baseline levels) (AERO-PA), or a control group (CON). The AERO and AERO-PA groups performed supervised aerobic training (3-4 times per week). The AERO-PA group wore Fitbit One accelerometers and received behavioral coaching to increase non-exercise physical activity.

RESULTS

There was a larger increase in fitness in the AERO-PA group (0.27 L/min, 0.16 to 0.40) compared to the AERO group (0.09 L/min, CI: -0.04 to 0.22) and the CON (0.01, CI: -0.11 to 0.12) groups. While significant findings were not observed in the entire study sample, when the analysis was restricted to participants compliant to the intervention (N=33), we observed significant reductions in waist circumference, percent weight loss, body fat, 2-hr glucose and 2-hr insulin in comparison to the CON group (p<0.05), but not the AERO group. Further, linear regression models showed that change in steps was associated with 21% and 26% of the variation in percent weight loss and percent fat loss, respectively.

CONCLUSION

Increasing non-exercise physical activity with aerobic training may represent a viable strategy to augment the fitness response in comparison to aerobic training alone and has promise for other health indicators.

Prescribed exercise to Reduce Recidivism After Weight Loss-Pilot (PREVAIL-P): Design, methods and rationale

Clinically significant weight loss is associated with health benefits for overweight and obese adults. Participation in adequate amounts of physical activity is critical for weight maintenance. However, the recommended amount of physical activity needed to promote weight maintenance is based primarily on retrospective studies that quantified physical activity levels through questionnaires which tend to overestimate physical activity levels. In addition, the present literature has provided little data on the impact of these physical activity levels on cardiovascular and diabetes risk factors, which may have equal or more clinical importance than weight changes. The Prescribed Exercise to Reduce Recidivism After Weight Loss-Pilot (PREVAIL-P) study will evaluate the effect of aerobic exercise training amount on weight maintenance following clinically significant weight loss in overweight and obese adults (BMI 25-40 kg/m2) age 30-65 years. Participants (N = 39) will complete a 10-week OPTIFAST® weight loss program with supervised aerobic exercise training. Individuals who achieve ≥7% weight loss from baseline will be subsequently randomized to levels of aerobic training consistent with physical activity recommendations (PA-REC) or weight maintenance recommendations (WM-REC) for 18 additional weeks. The primary outcome of the PREVAIL-P study will be change in weight from the completion of OPTIFAST® program to the end of the study. Notable secondary measures include changes in clinically relevant cardiometabolic risk factors between study groups (e.g. blood lipids concentrations, oral glucose tolerance, arterial stiffness). This pilot study will be used to estimate the effect sizes needed for a randomized controlled trial on this topic.

A Randomized Community-based Exercise Training Trial in African American Men: Aerobic Plus Resistance Training and Insulin Sensitivity in African American Men

PURPOSE

To examine the impact of a community-based exercise training intervention on cardiometabolic outcomes in African American men who have a family history of type 2 diabetes.

METHODS

The Aerobic Plus Resistance Training and Insulin Sensitivity in African American Men (ARTIIS) study randomized participants into either an exercise training intervention or an information only control group for 5 months. The exercise training intervention consisted of 150 min of moderate intensity aerobic activity and 2 d of resistance training per week, consistent with the current federal physical activity guidelines. Participants in the control group received monthly newsletters featuring topics focused heavily on type 2 diabetes education and prevention. Outcome data were analyzed using repeated-measures ANCOVA models and incorporating both intention-to-treat and per-protocol principles.

RESULTS

Adherence to the aerobic and resistance training prescriptions were between 77% and 79%. Despite significant within group improvements in glucose and insulin levels (fasting, 2 h, 2 h minus baseline) and Homeostatic Model 2-Insulin Resistance, there were not significant between group differences. There was a marginally significant between group difference for Homeostatic Model 2-Beta (P < 0.06), and significant between group differences in peak cardiorespiratory fitness (P < 0.001) and waist circumference (P = 0.03).

CONCLUSIONS

These findings suggest that exercise training in accordance with the current national recommendations is effective in improving some health parameters in middle-age African American men who have a family history of type 2 diabetes, but did not have a significant impact on glycemic status.

High-intensity exercise to promote accelerated improvements in cardiorespiratory fitness (HI-PACE): study protocol for a randomized controlled trial

Background

African Americans have a disproportionate prevalence and incidence of type 2 diabetes compared with Caucasians. Recent evidence indicates that low cardiorespiratory fitness (CRF) level, an independent risk factor for type 2 diabetes, is also more prevalent in African Americans than Caucasians. Numerous studies in Caucasian populations suggest that vigorous exercise intensity may promote greater improvements in CRF and other type 2 diabetes risk factors (e.g., reduction of glucose/insulin levels, pulse wave velocity, and body fat) than moderate intensity. However, current evidence comparing health benefits of different aerobic exercise intensities on type 2 diabetes risk factors in African Americans is negligible. This is clinically important as African Americans have a greater risk for type 2 diabetes and are less likely to meet public health recommendations for physical activity than Caucasians. The purpose of the HI-PACE (High-Intensity exercise to Promote Accelerated improvements in CardiorEspiratory fitness) study is to evaluate whether high-intensity aerobic exercise elicits greater improvements in CRF, insulin action, and arterial stiffness than moderate-intensity exercise in African Americans.

Methods/Design

A randomized controlled trial will be performed on overweight and obese (body mass index of 25–45 kg/m²) African Americans (35–65 years) (n = 60). Participants will be randomly assigned to moderate-intensity (MOD-INT) or high-intensity (HIGH-INT) aerobic exercise training or a non-exercise control group (CON) for 24 weeks. Supervised exercise will be performed at a heart rate associated with 45–55% and 70–80% of VO₂ max in the MOD-INT and HIGH-INT groups, respectively, for an exercise dose of 600 metabolic equivalents of task (MET)-minutes per week (consistent with public health recommendations). The primary outcome is change in CRF. Secondary outcomes include change in insulin sensitivity (measured via an intravenous glucose tolerance test), skeletal muscle mitochondrial oxidative capacity (via near-infrared spectroscopy), skeletal muscle measurements (i.e., citrate synthase, COX IV, GLUT-4, CPT-1, and PGC1-α), arterial stiffness (via carotid-femoral pulse wave velocity), body fat, C-reactive protein, and psychological outcomes (quality of life/exercise enjoyment).

Discussion

The anticipated results of the HI-PACE study will provide vital information on the health effects of high-intensity exercise in African Americans. This study will advance health disparity research and has the potential to influence future public health guidelines for physical activity.

Trial registration

ClinicalTrials.gov identifier: NCT02892331. Registered on September 8, 2016.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3611-1) contains supplementary material, which is available to authorized users.

Telemedicine-Based Health Coaching Is Effective for Inducing Weight Loss and Improving Metabolic Markers

BACKGROUND

To assess the efficacy of health coaching (HC) delivered through videoconferencing (VC) to favorably change physical activity (PA), weight, and metabolic markers in adults with high body mass index (BMI).

MATERIALS AND METHODS

Thirty adults (BMI ≥30 kg/m2) were randomly assigned to one of three groups: VC, in-person (IP), or control group (CG). Participants received wireless watches and weight scales to sync with their personal smartphones; recorded data were wirelessly uploaded to a secure database. Participants assigned to VC and IP received individualized HC by a multidisciplinary team (registered dietitian, exercise physiologist, and medical doctor) based on data uploaded over the 12-week intervention. Steps/day and weight loss were analyzed through analyses of covariance.

RESULTS

Within- and between-group changes in weight (kg), glucose, insulin, hemoglobin A1c (HbA1c), and Homeostasis Model Assessment estimate of insulin resistance (HOMA-IR) were analyzed through analyses of variance. Weight loss was greater (p < 0.05) for VC (8.23 ± 4.5 kg; 7.7%) than IP (3.2 ± 2.6 kg; 3.4%) and CG (2.9 ± 3.9 kg; 3.3%), respectively. Steps/day were significantly higher in VC than IP at week 4 and VC was significantly higher than the CG at weeks 6, 8, 9, and 11 (p ≤ 0.05). No within- or between-group differences were found for glucose, insulin, or HbA1C. HOMA-IR decreased for VC only (p ≤ 0.05).

CONCLUSIONS

Our innovative, multidisciplinary, telemedicine HC delivered through VC led to more favorable changes in weight loss, PA (steps/day), and HOMA-IR than IP or no HC. VC may be an economical approach to improve health and promote behavior change in obese adults.

CLINICAL TRIAL REGISTRATION NUMBER

ClinicalTrials.gov identifier NCT03278951.

The Effects of Exercise and Physical Activity on Weight Loss and Maintenance

Obesity represents a major health problem in the United States and is associated with increased prevalence of cardiovascular (CV) disease risk factors. Physical activity (PA) and exercise training (ET) are associated with reduced CV risk, improved cardiometabolic risk factors, and facilitated weight loss through creating a negative energy balance. Clinicians need to counsel overweight and obese patients on how much PA/ET is needed to promote weight loss and weight loss maintenance. This will help establish realistic expectations and maximize improvements in CV risk factors. Although the minimum guidelines for aerobic PA (150 min of moderate or 75 min of vigorous physical activity per week) can improve CV health, these levels are generally inadequate for clinically significant weight loss or weight maintenance without caloric restriction. The purpose of this review is to evaluate the role of ET to promote clinically significant weight loss and promote weight maintenance. In particular, we will evaluate the likelihood of weight loss from ET programs composed of aerobic training only, resistance training only and programs that combine diet and ET. We will also explore the role of PA in promoting short-term and long-term weight maintenance.

Effects of aerobic training with and without weight loss on insulin sensitivity and lipids

Purpose

The purpose of this study is to evaluate the effect of exercise training with modest or greater weight loss (≥3%) or not (<3%) on insulin sensitivity, lipoprotein concentrations, and lipoprotein particle size in overweight and obese participants.

Methods

Adults (N = 163, body mass index: 25–37 [kg/m²]) participated in 8 months of exercise training. Insulin sensitivity, lipid concentrations, lipid particle size and other cardiometabolic variables were measured at baseline and follow-up. Participants were categorized by whether they achieved at least modest weight loss (≥ 3%) or not (<3%) following the intervention.

Results

A greater improvement in insulin sensitivity was observed in adults performing exercise training with at least modest weight loss (2.2 mU·l^-1 ·min ^-1, CI: 1.5 to 2.8) compared to those who did not (0.8 mU·l^-1 ·min ^-1, CI: 0.5 to 1.2). Similar results were observed for acute insulin response, triglycerides, non-HDL cholesterol concentration, low density lipoprotein (LDL) particle size and high density lipoprotein (HDL) particle size (p<0.05), when all exercise groups were combined. No significant results across weight loss categories were observed for LDL, HDL, glucose, or insulin levels.

Conclusion

The present study suggests that aerobic exercise combined with at least modest weight loss leads to greater improvements in insulin sensitivity, triglycerides as well as other non-traditional lipid risk factors (non-HDL cholesterol, HDL/LDL particle size). Clinicians should advocate patients who are overweight/obese to exercise and obtain modest weight loss for improved cardiovascular benefits.

Effects of clinically significant weight loss with exercise training on insulin resistance and cardiometabolic adaptations

OBJECTIVE

To determine response rates for clinically significant weight loss (CWL) following different aerobic exercise training amounts and whether enhanced cardiometabolic adaptations are observed with CWL compared to modest weight loss (MWL) or neither.

METHODS

Participants (N = 330) performed 6 months of aerobic training at 4 kcal per kilogram per week (KKW), 8 KKW, or 12 KKW (50%, 100%, and 150% of recommended levels respectively). Weight loss was categorized as CWL (≥5%) or MWL (3.0% to 4.9%) or neither.

RESULTS

The CWL response rate was greater in the 8 KKW group (20.2%, CI: 13.0% to 27.5%) compared to 4 KKW (10.3%, CI: 4.6% to 16.0%), but not compared to the 12 KKW group (14.6%, CI: 7.6% to 21.6%). Reductions in HOMA-IR were observed in participants with CWL (-0.60, CI: -0.98 to -0.22) and with MWL (-0.48, CI: -0.87 to -0.10), but not those who achieved neither (-0.06, CI -0.22 to 0.10). No changes between groups were observed for cholesterol, fitness, or blood pressure.

CONCLUSIONS

Low response rates for CWL were observed following training, even at levels above recommended levels. Achieving MWL with exercise may represent a reasonable initial weight loss target since the improvement in insulin resistance with MWL is similar to what is achieved with CWL.

Association between Changes in Muscle Quality with Exercise Training and Changes in Cardiorespiratory Fitness Measures in Individuals with Type 2 Diabetes Mellitus: Results from the HART-D Study

Introduction

Type 2 diabetes mellitus (T2DM) is associated with a reduction in muscle quality. However, there is inadequate empirical evidence to determine whether changes in muscle quality following exercise are associated with improvement in cardiorespiratory fitness (CRF) in individuals with T2DM. The objective of this study was to investigate the association between change in muscle quality following a 9-month intervention of aerobic training (AT), resistance training (RT) or a combination of both (ATRT) and cardiorespiratory fitness (CRF) in individuals with T2DM.

Material and Methods

A total of 196 participants were randomly assigned to a control, AT, RT, or combined ATRT for a 9-months intervention. The exposure variable was change in muscle quality [(Post: leg muscle strength/leg muscle mass)-[(Pre: leg muscle strength/leg muscle mass)]. Dependent variables were change in CRF measures including absolute and relative VO_2peak, and treadmill time to exhaustion (TTE) and estimated metabolic equivalent task (METs).

Results

Continuous change in muscle quality was independently associated with change in absolute (β = 0.015; p = 0.019) and relative (β = 0.200; p = 0.005) VO_2peak, and TTE (β = 0.170; p = 0.043), but not with estimated METs (p > 0.05). A significant trend was observed across tertiles of change in muscle quality for changes in absolute (β = 0.050; p = 0.005) and relative (β = 0.624; p = 0.002) VO_2peak following 9 months of exercise training. No such association was observed for change in TTE and estimated METs (p > 0.05).

Discussion

The results from this ancillary study suggest that change in muscle quality following exercise training is associated with a greater improvement in CRF in individuals with T2DM. Given the effect RT has on increasing muscle quality, especially as part of a recommended training program (ATRT), individuals with T2DM should incorporate RT into their AT regimens to optimize CRF improvement.

Trial Registration

Clinicaltrials.gov NCT00458133

Metabolic Effects of Exercise Training Among Fitness-Nonresponsive Patients With Type 2 Diabetes: The HART-D Study

OBJECTIVE

To evaluate the impact of exercise training (ET) on metabolic parameters among participants with type 2 diabetes mellitus (T2DM) who do not improve their cardiorespiratory fitness (CRF) with training.

RESEARCH DESIGN AND METHODS

We studied participants with T2DM participating in the Health Benefits of Aerobic and Resistance Training in Individuals With Type 2 Diabetes (HART-D) trial who were randomized to a control group or one of three supervised ET groups for 9 months. Fitness response to ET was defined as a change in measured peak absolute oxygen uptake (ΔVO(2peak), in liters per minute) from baseline to follow-up. ET participants were classified based on ΔVO(2peak) into fitness responders (ΔVO(2peak) ≥5%) and nonresponders (ΔVO(2peak) <5%), and changes in metabolic profiles were compared across control, fitness responder, and fitness nonresponder groups.

RESULTS

A total of 202 participants (mean age 57.1 ± 7.9 years, 63% women) were included. Among the exercise groups (n = 161), there was substantial heterogeneity in ΔVO(2peak); 57% had some improvement in CRF (ΔVO(2peak) >0), with only 36.6% having a ≥5% increase in VO(2peak). Both fitness responders and nonresponders (respectively) had significant improvements in hemoglobin A1c and measures of adiposity (ΔHbA(1c): -0.26% [95% CI -0.5 to -0.01] and -0.26% [-0.45 to -0.08]; Δwaist circumference: -2.6 cm [-3.7 to -1.5] and -1.8 cm [-2.6 to -1.0]; Δbody fat: -1.07% [-1.5 to -0.62] and -0.75% [-1.09 to -0.41]). No significant differences were observed in the degree of change of these metabolic parameters between fitness responders and nonresponders. Control group participants had no significant changes in any of these metabolic parameters.

CONCLUSIONS

ET is associated with significant improvements in metabolic parameters irrespective of improvement in cardiorespiratory fitness.

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.

Aerobic and strength training in concomitant metabolic syndrome and type 2 diabetes

PURPOSE

Concomitant type 2 diabetes (T2D) and metabolic syndrome exacerbates mortality risk; yet, few studies have examined the effect of combining (AER + RES) aerobic (AER) and resistance (RES) training for individuals with T2D and metabolic syndrome.

METHODS

We examined AER, RES, and AER + RES training (9 months) commensurate with physical activity guidelines in individuals with T2D (n = 262; 63% female, 44% black). Primary outcomes were change in, and prevalence of, metabolic syndrome score at follow-up (mean and 95% confidence interval [CI]). Secondary outcomes included maximal cardiorespiratory fitness (VO2peak) and estimated METs from time-to-exhaustion (TTE) and exercise efficiency calculated as the slope of the line between ventilatory threshold, respiratory compensation, and maximal fitness. General linear models and bootstrapped Spearman correlations were used to examine changes in metabolic syndrome associated with training primary and secondary outcome variables.

RESULTS

We observed a significant decrease in metabolic syndrome scores (P for trend = 0.003) for AER (-0.59, 95% CI = -1.00 to -0.21) and AER + RES (-0.79, 95% CI = -1.40 to -0.35), both being significant (P ≤ 0.02) versus control (0.26, 95% CI = -0.58 to 0.40) and RES (-0.13, 95% CI = -1.00 to 0.24). This led to a reduction in metabolic syndrome prevalence for the AER (56% vs 43%) and AER + RES (55% vs 46%) groups between baseline and follow-up. The observed decrease in metabolic syndrome was mediated by significant improvements in exercise efficiency for the AER and AER + RES training groups (P < 0.05), which was more strongly related to TTE (25%-30%; r = -0.38, 95% CI = -0.55 to -0.19) than VO2peak (5%-6%; r = -0.24, 95% CI = -0.45 to -0.01).

CONCLUSIONS

AER and AER + RES training significantly improved metabolic syndrome scores and prevalence in patients with T2D. These improvements appear to be associated with improved exercise efficiency and are more strongly related to improved TTE versus VO2peak.

Uncovering physiological mechanisms for health disparities in type 2 diabetes

Type 2 diabetes (T2D) prevalence in the United States is significantly higher in African Americans vs Whites. Yet, the physiological mechanisms contributing to this health disparity have been poorly described. To design effective strategies to reduce this disparity, there is a need to determine whether racial differences in diabetes prevalence are attributable to modifiable or non-modifiable factors. This review synthesizes and critically evaluates the potential physiological and genetic mechanisms that may contribute to the higher susceptibility of African Americans to T2D. These mechanisms include: 1) obesity and fat distribution; 2) metabolic flexibility; 3) muscle physiology; 4) energy expenditure and fitness; and 5) genetics. We focus on the clinical significance of findings and limitations of the recent literature.

Implementation and adherence issues in a workplace treadmill desk intervention

We report experiences, observations, and general lessons learned, specifically with regards to participant recruitment and adherence, while implementing a 6-month randomized controlled treadmill desk intervention (the WorkStation Pilot Study) in a real-world office-based health insurance workplace. Despite support from the company’s upper administration, relatively few employees responded to the company-generated e-mail to participate in the study. Ultimately only 41 overweight/obese participants were deemed eligible and enrolled from a recruitment pool of 728 workers. Participants allocated to the Treadmill Desk Group found the treadmill desk difficult to use for 45 min twice a day as scheduled. Overall attendance averaged 45%–50% of all possible scheduled sessions. The most frequently reported reasons for missing sessions included work conflict (35%), out of office (30%), and illness/injury/drop-out (20%). Although focus groups indicated consistently positive comments about treadmill desks, an apparent challenge was fitting a rigid schedule of shared use to an equally rigid and demanding work schedule punctuated with numerous tasks and obligations that could not easily be interrupted. Regardless, we documented that sedentary office workers average ∼43 min of light-intensity (∼2 METs) treadmill walking daily in response to a scheduled, facilitated, and shared access workplace intervention. Workstation alternatives that combine computer-based work with light-intensity physical activity are a potential solution to health problems associated with excessive sedentary behavior; however, there are numerous administrative, capital, and human resource challenges confronting employers considering providing treadmill desks to workers in a cost-effective and equitable manner.

Clinical Strategies for Managing Dyslipidemias

There is substantial evidence that lipids are critical in the development and progression of atherosclerotic cardiovascular disease. In November 2013, the American College of Cardiology/American Heart Association in conjunction with the National Cholesterol Education Program IV developed new guidelines for the treatment of blood cholesterol. In this report, we review these new guidelines and emphasize the potential benefits of physical activity and exercise training on plasma lipids.

Cancer survival through lifestyle change (CASTLE): a pilot study of weight loss

BACKGROUND

Excess weight is a strong predictor of incident breast cancer (BC) and survivorship. A limited number of studies comparing strategies for promoting successful weight loss in women with remitted BC exist.

PURPOSE

CASTLE was a pilot study comparing the effectiveness/feasibility of in-person and telephonic behavioral-based lifestyle weight loss interventions in BC survivors.

METHOD

Fifty-two overweight/obese women (BMI = 25-45 kg/m(2)) with remitted BC (stages I-IIIa) who recently completed cancer treatment were assigned to either an in-person group (n = 24) or an individual telephone-based condition (n = 11). Both interventions focused on increasing physical activity and reducing caloric intake. The phase I intervention lasted 6 months. The in-person condition received 16 group-based sessions, and the telephone condition received intervention calls approximately weekly. Phase II lasted 6 months (e.g., months 6-12), and all participants received monthly intervention calls via telephone.

RESULTS

Participants were predominately Caucasian (80 %) with a mean age of 52.8 (8.0) years and BMI of 31.9 (5.4) kg/m(2). Mixed models ANOVAs showed significant within group weight loss after 6 months for both the in-person (-3.3 kg ± 4.4, p = 0.002) and the telephonic (-4.0 kg ± 6.0, p = 0.01) conditions with no between group differences. During phase II, the in-person group demonstrated significant weight regain (1.3 kg ± 1.7, p = 0.009).

CONCLUSION

Our pilot study findings demonstrated that telephone-based behavioral weight loss programs are effective and feasible in BC survivors and that telephonic programs may have advantages in promoting weight loss maintenance.

Low fitness partially explains resting metabolic rate differences between African American and white women

BACKGROUND

High levels of obesity among African American women have been hypothesized to be partially resultant from a lower resting metabolic rate compared with white women. The aim of the current study was to determine if differences in cardiorespiratory fitness and moderate-to-vigorous physical activity are associated with differences in resting metabolic rate among free-living young adult African American women and white women.

METHODS

Participants were 179 women (white women n = 141, African American women n = 38, mean age = 27.7 years). Resting metabolic rate was measured using indirect calorimetry, body composition using dual energy x-ray absorptiometry, cardiorespiratory fitness via maximal treadmill test, and moderate-to-vigorous physical activity using an activity monitor.

RESULTS

African American women had higher body mass index, fat mass, and fat-free mass compared with white women but lower levels of cardiorespiratory fitness. No differences were observed between African American and white women in resting metabolic rate when expressed as kcal/day (1390.8 ± 197.5 vs 1375.7 ± 173.6 kcal/day, P = .64), but African American women had a lower resting metabolic rate when expressed relative to body weight (2.56 ± 0.30 vs 2.95 ± 0.33 mL/kg/min, P < .001). After statistical adjustment for differences in body composition between groups using linear regression models, African American women had a lower resting metabolic rate compared with white women (1299.4 ± 19.2 vs 1400.4 ± 9.2 kcal/day, P < .001). The addition of cardiorespiratory fitness reduced the differences among groups by 25%. The addition of moderate-to-vigorous physical activity did not improve the model.

CONCLUSIONS

The present study confirms that African American women have a lower resting metabolic rate compared with their white peers, and low cardiorespiratory fitness explained 25% of this difference. Variables associated with resting metabolic rate, such as cardiorespiratory fitness, represent possible points of tailored interventions designed to address high levels of obesity seen in certain demographic groups.

WalkMore: a randomized controlled trial of pedometer-based interventions differing on intensity messages

BACKGROUND

Pedometer-based programs have elicited increased walking behaviors associated with improvements in blood pressure in sedentary/low active postmenopausal women, a population at increased risk of cardiovascular disease. Such programs typically encourage increasing the volume of physical activity with little regard for its intensity. Recent advances in commercially available pedometer technology now permit tracking of both steps/day and time in moderate (or greater) intensity physical activity on a daily basis. It is not known whether the dual message to increase steps/day while also increasing time spent at higher intensity walking will elicit additional improvements in blood pressure relative to a message to only focus on increasing steps/day. The purpose of this paper is to present the rationale, study design, and protocols employed in WalkMore, a 3-arm 3-month blinded and randomized controlled trial (RCT) designed to compare the effects of two community pedometer-based walking interventions (reflecting these separate and combined messages) relative to a control group on blood pressure in sedentary/low active post-menopausal women, a population at increased risk of cardiovascular disease.

METHODS/DESIGN

120 sedentary/low active post-menopausal women (45-74 years of age) will be randomly assigned (computer-generated) to 1 of 3 groups: A) 10,000 steps/day (with no guidance on walking intensity/speed/cadence; BASIC intervention, n = 50); B) 10,000 steps/day and at least 30 minutes in moderate intensity (i.e., a cadence of at least 100 steps/min; ENHANCED intervention, n = 50); or a Control group (n = 20). An important strength of the study is the strict control and quantification of the pedometer-based physical activity interventions. The primary outcome is systolic blood pressure. Secondary outcomes include diastolic blood pressure, anthropometric measurements, fasting blood glucose and insulin, flow mediated dilation, gait speed, and accelerometer-determined physical activity and sedentary behavior.

DISCUSSION

This study can make important contributions to our understanding of the relative benefits that walking volume and/or intensity may have on blood pressure in a population at risk of cardiovascular disease.

TRIAL REGISTRATION

ClinicalTrials.gov Record NCT01519583, January 18, 2012.

Predictors of improvement in endothelial function after exercise training in a diverse sample of postmenopausal women

BACKGROUND

Endothelial dysfunction measured via flow-mediated dilation (FMD) is associated with greater risk of future hypertension and cardiovascular events in postmenopausal women. Aerobic exercise training has been shown to improve endothelial function in Caucasian populations, but has not been evaluated specifically in African Americans. This has clinical importance due to the increased prevalence of cardiovascular disease in African Americans.

METHODS

In the present pilot study, 8 African American (age: 55.8±1.7 years, peak oxygen uptake [VO2 peak]: 21.0±3.9 mL/kg/minute, body mass index [BMI]: 30.1± 6.3 kg/m(2)) and 16 Caucasian (age: 57.2±5.9 years, VO2 peak: 21.8±3.7 mL/kg/minute, BMI: 29.3±5.2 kg/m(2)) sedentary postmenopausal women underwent brachial artery FMD measurements before and after 12 weeks of aerobic exercise training. FMD was quantified by comparing B-mode ultrasound images of the brachial artery at rest and following reactive hyperemia after 5 minutes of forearm occlusion. Participants performed aerobic exercise training 4 days per week for 12 weeks.

RESULTS

Despite improvements in fitness in both groups, aerobic exercise training did not significantly improve FMD in African American (5.8% to 5.7%, p=0.950) or Caucasian postmenopausal women (5.7% to 6.6%, p=0.267). In women with the greatest impairment in endothelial function at baseline (FMD<4.5%), a significant improvement in FMD was observed, independent of race, following exercise training (2.2% to 6.2%, p=0.007).

CONCLUSION

The benefits of aerobic exercise training on endothelial function in postmenopausal women are most pronounced in women with endothelial dysfunction prior to training and do not appear to be affected by race.

The role of exercise and physical activity in weight loss and maintenance

This review explores the role of physical activity (PA) and exercise training (ET) in the prevention of weight gain, initial weight loss, weight maintenance, and the obesity paradox. In particular, we will focus the discussion on the expected initial weight loss from different ET programs, and explore intensity/volume relationships. Based on the present literature, unless the overall volume of aerobic ET is very high, clinically significant weight loss is unlikely to occur. Also, ET also has an important role in weight regain after initial weight loss. Overall, aerobic ET programs consistent with public health recommendations may promote up to modest weight loss (~2 kg), however the weight loss on an individual level is highly heterogeneous. Clinicians should educate their patients on reasonable expectations of weight loss based on their physical activity program and emphasize that numerous health benefits occur from PA programs in the absence of weight loss.

Categorical analysis of the impact of aerobic and resistance exercise training, alone and in combination, on cardiorespiratory fitness levels in patients with type 2 diabetes: results from the HART-D study

OBJECTIVE

Low cardiorespiratory fitness (CRF) is an independent risk factor for cardiovascular disease (CVD), especially in individuals with type 2 diabetes. Age-predicted, sex-stratified, and maximal MET cut points have been developed to determine the risk of CVD events and mortality in low CRF categories. We examined the proportion of Health Benefits of Aerobic and Resistance Training in Individuals With Type 2 Diabetes (HART-D) participants above these cut points before and after 9 months of aerobic training (AT), resistance training (RT), or a combination of both (ATRT).

RESEARCH DESIGN AND METHODS

Participants from the HART-D study (n=196) who were randomly assigned to exercise training (AT, RT, or ATRT) or to a nonexercise control group between April 2007 and August 2009 were used in this ancillary study. Cut points were previously established for age-predicted METs (>100% and >85%, mean and increased CVD risk, respectively), age- and sex-stratified METs (Aerobic Center Longitudinal Study), and clinically discernible METs (men>8.0, women>6.5).

RESULTS

Baseline prevalence of participants above these cut points was similar for all intervention groups (P>0.50) and ranged from 11.9% (>100% age predicted) to 55.1% (>85% age predicted). Baseline prevalence and age-, sex-, and race/ethnic group-adjusted percentage of participants above each cut point increased significantly after AT and ATRT (P<0.05 for all).

CONCLUSIONS

Structured exercise training, especially the AT component, was associated with a greater number of participants moving above established cut points indicative of low CRF. These results have public health and clinical implications for the growing number of patients with type 2 diabetes at high risk for CVD.

Changes in body fat distribution and fitness are associated with changes in hemoglobin A1c after 9 months of exercise training: results from the HART-D study

OBJECTIVE

To investigate the associations between changes in body composition and fitness after exercise training and changes in hemoglobin A1c (HbA1c) in individuals with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Participants (n = 201) were randomized to aerobic, resistance, or combined training for 9 months. HbA1c, waist circumference, total and trunk fat mass, appendicular fat mass, lean body mass, isokinetic leg muscle strength, peak O2 uptake, and estimated METs were assessed at baseline and follow-up. Change in HbA1c was evaluated across quartiles of change in body composition and fitness.

RESULTS

Change in HbA1c was associated with changes in body weight (r = 0.13, P = 0.052), waist circumference (r = 0.17, P = 0.013), trunk fat mass (r = 0.19, P = 0.005), and estimated METs (r = -0.16, P = 0.023). There was a trend in change in HbA1c across quartiles of waist circumference (P = 0.011), trunk fat mass (P = 0.020), and estimated METs (P = 0.011). Participants with increased estimated METs and reduced trunk fat mass had greater odds of having reduced HbA1c after training (3.48, 1.46-8.31). Finally, participants with increased estimated METs and reduced waist circumference were 2.81 (1.13-6.98) times more likely to have reduced HbA1c and type 2 diabetes medication use than those without improved fitness and central adiposity.

CONCLUSIONS

In patients with type 2 diabetes, a reduction in central adiposity and increase in fitness were the most prominent predictors of the change in HbA1c in response to exercise training.

Exercise training and quality of life in individuals with type 2 diabetes: a randomized controlled trial

OBJECTIVE

To establish whether exercise improves quality of life (QOL) in individuals with type 2 diabetes and which exercise modalities are involved.

RESEARCH DESIGN AND METHODS

Health Benefits of Aerobic and Resistance Training in individuals with type 2 Diabetes (HART-D; n = 262) was a 9-month exercise study comparing the effects of aerobic training, resistance training, or a combination of resistance and aerobic training versus a nonexercise control group on hemoglobin A1c (HbA1c) in sedentary individuals with type 2 diabetes. This study is an ancillary analysis that examined changes in QOL after exercise training using the Short Form-36 Health Survey questionnaire compared across treatment groups and with U.S. national norms.

RESULTS

The ancillary sample (n = 173) had high baseline QOL compared with U.S. national norms. The QOL physical component subscale (PCS) and the general health (GH) subscale were improved by all three exercise training conditions compared with the control group condition (resistance: PCS, P = 0.005; GH, P = 0.003; aerobic: PCS, P = 0.001; GH, P = 0.024; combined: PCS, P = 0.015; GH, P = 0.024). The resistance training group had the most beneficial changes in bodily pain (P = 0.026), whereas physical functioning was most improved in the aerobic and combined condition groups (P = 0.025 and P = 0.03, respectively). The changes in the mental component score did not differ between the control group and any of the exercise groups (all P > 0.05). The combined training condition group had greater gains than the aerobic training condition group in the mental component score (P = 0.004), vitality (P = 0.031), and mental health (P = 0.008) and greater gains in vitality compared with the control group (P = 0.021).

CONCLUSIONS

Exercise improves QOL in individuals with type 2 diabetes. Combined aerobic/resistance exercise produces greater benefit in some QOL domains.

Dose effect of cardiorespiratory exercise on metabolic syndrome in postmenopausal women

As an ancillary report to a large National Institutes of Health (NIH)-funded trial, we examined the effects of 6 months of exercise training at 50%, 100%, and 150% of the NIH Consensus Recommendations for physical activity (i.e., 4, 8, and 12 kcal/kg of energy expenditure/wk [KKW]) versus a nonexercise control group on the metabolic syndrome (MS) in sedentary, overweight, moderately hypertensive, postmenopausal women. We examined the clinically defined National Cholesterol Education Program MS, individual components scores, and summed z-scores, expressed as a continuous variable (zMS), using chi-square and general linear models to assess the clinical and progressive nature of MS, respectively. Our results showed significant improvements in zMS for all exercise groups and MS for the 8- and 12 KKW groups only (all, p for trend = 0.02). Post hoc analyses showed that 12 KKW for zMS and 8 and 12 KKW for MS was significant versus the control group (all, p <0.05). When examining the composite scores, we observed significant trends for improvement in waist circumference (p for trend = 0.001), fasting glucose (p for trend = 0.01), and systolic blood pressure (p for trend = 0.02), which appeared to be dose dependent, given the additive nature for incorporating the within-group improvements in waist circumference (4, 8, and 12 KKW), fasting glucose (8 and 12 KKW), and systolic blood pressure (12 KKW). Our results suggest that low-to-moderate intensity cardiorespiratory exercise appears to improve components of the MS in postmenopausal women at levels at or greater than NIH recommendations and that zMS improves at half the NIH recommendations. Greater levels of energy expenditure appear to enhance this effect by incorporating a greater number of requisite MS composite scores.

Racial differences in the response of cardiorespiratory fitness to aerobic exercise training in Caucasian and African American postmenopausal women

African American (AA) women have an elevated risk of cardiovascular disease and have been reported to have lower cardiorespiratory fitness (CRF) compared with Caucasian American (CA) women. However, little data exist that evaluate racial differences in the change in CRF following aerobic exercise training. CA (n = 264) and AA (n = 122) postmenopausal women from the Dose-Response to Exercise in Women study were randomized to 4, 8, and 12 kcal·kg body wt(-1)·wk(-13) (KKW) of aerobic training or the control group for 6 mo. CRF was evaluated using a cycle ergometer. A greater increase in relative CRF was observed in CA compared with AA women in the 4 (CA: 1.00 vs. AA: 0.35 ml O2·kg(-1)·min (-1), P = 0.034), 8 (CA: 1.59 vs. AA: 0.82 ml O2·kg(-1)·min (-1), P = 0.041), and 12 (CA: 1.98 vs. AA: 0.50 ml O2·kg(-1)·min (-1), P = 0.001) KKW groups. Similar effects were found in absolute CRF, with the exception of the 4-KKW (CA: 0.04 vs. AA: 0.02 l O2/min, P = 0.147) group. However, in categorical analyses, the percentages of women who improved in both relative (>0 ml O2·kg(-1)·min (-1)) and absolute (>0 l O2/min) CRF were not significantly different for CA and AA women in all exercise groups (all P > 0.05). AA postmenopausal women, in general, had an attenuated increase in CRF (both relative and absolute) following exercise training, but had similar response rates compared with CA women. Future studies should investigate the physiologic mechanisms responsible for this attenuated response.

Physical activity, cardiorespiratory fitness, and exercise training in primary and secondary coronary prevention

Substantial data have established that higher levels of physical activity (PA), participating in exercise training (ET), and higher overall cardiorespiratory fitness (CRF) provide considerable protection in the primary and secondary prevention of coronary heart disease (CHD). This review surveys data from epidemiological and prospective ET studies supporting the favorable impact of PA, ET, and CRF in primary CHD prevention. Clearly, cardiac rehabilitation and ET (CRET) programs have been underutilized for patients with CHD, particularly considering the effect of CRET on CHD risk factors, including CRF, obesity indices, fat distribution, plasma lipids, inflammation, and psychological distress, as well as overall morbidity and mortality. These data strongly support the routine referral of patients with CHD to CRET programs and that patients should be vigorously encouraged to attend CRET following major CHD events.

Evaluation of racial differences in resting and postprandial endothelial function in postmenopausal women matched for age, fitness and body composition

OBJECTIVE

We investigated endothelial function at rest and after a high-fat meal challenge in African American (AA) and Caucasian postmenopausal women matched for age, body mass index, percent fat and fitness level.

DESIGN

Pilot study.

SETTING

University of Virginia General Clinical Research Center.

PARTICIPANTS

Eight AA and 8 Caucasian postmenopausal women.

INTERVENTION

PARTICIPANTS underwent a VO2 peak treadmill protocol, percent fat assessment, and brachial artery flow-mediated dilation measurements (baseline and 4 hours following a high-fat meal).

MAIN OUTCOMES MEASURES

Baseline and postprandial flow mediated dilation (FMD) following a high-fat meal.

RESULTS

FMD values were similar in AA (5.4%, 95% CI: 3.3, 7.4) and Caucasian women (4.0%, 95% CI: 2.0, 6.1). There was no significant change in FMD from baseline to four hours following the meal challenge within groups (AA: .9%, P = .397, Caucasian: 2.3%, P = .063) or between groups (P = .449), despite a significant increase in triglycerides (AA: 81.8 mg/dL, P < .001, Caucasian: 99.7 mg/dL, P = .004).

CONCLUSIONS

The present pilot study found that when postmenopausal AA and Caucasian women are matched for age, fitness and body composition, reported racial differences in resting endothelial function were not observed. Additionally, there were no racial differences in postprandial endothelial function or metabolism following a high-fat meal.