Leslie H. Willis

Effects of aerobic and/or resistance training on body mass and fat mass in overweight or obese adults

Recent guidelines on exercise for weight loss and weight maintenance include resistance training as part of the exercise prescription. Yet few studies have compared the effects of similar amounts of aerobic and resistance training on body mass and fat mass in overweight adults. STRRIDE AT/RT, a randomized trial, compared aerobic training, resistance training, and a combination of the two to determine the optimal mode of exercise for obesity reduction. Participants were 119 sedentary, overweight or obese adults who were randomized to one of three 8-mo exercise protocols: 1) RT: resistance training, 2) AT: aerobic training, and 3) AT/RT: aerobic and resistance training (combination of AT and RT). Primary outcomes included total body mass, fat mass, and lean body mass. The AT and AT/RT groups reduced total body mass and fat mass more than RT (P < 0.05), but they were not different from each other. RT and AT/RT increased lean body mass more than AT (P < 0.05). While requiring double the time commitment, a program of combined AT and RT did not result in significantly more fat mass or body mass reductions over AT alone. Balancing time commitments against health benefits, it appears that AT is the optimal mode of exercise for reducing fat mass and body mass, while a program including RT is needed for increasing lean mass in middle-aged, overweight/obese individuals.

Comparison of Aerobic Versus Resistance Exercise Training Effects on Metabolic Syndrome (from the Studies of a Targeted Risk Reduction Intervention Through Defined Exercise - STRRIDE-AT/RT)

Aerobic training (AT) improves the metabolic syndrome (MS) and its component risk factors; however, to our knowledge, no randomized clinical studies have addressed whether resistance training (RT) improves the MS when performed alone or combined with AT. Sedentary, overweight dyslipidemic men and women, aged 18 to 70 years completed a 4-month inactive run-in period and were randomized to 1 of 3 eight-month exercise programs (n = 196). The exercise programs were (1) RT (3 days/week, 3 sets/day of 8 to 12 repetitions of 8 different exercises targeting all major muscle groups); (2) AT (∼120 minutes/week at 75% of the maximum oxygen uptake), and (3) AT and RT combined (AT/RT) (exact combination of AT and RT). Of the 196 randomized patients, 144 completed 1 of the 3 exercise programs. The 86 participants with complete data for all 5 MS criteria were used in the present analysis, and a continuous MS z score was calculated. Eight months of RT did not change the MS score. AT improved the MS score (p <0.07) and showed a trend toward significance compared to RT (p <0.10). AT/RT significantly decreased the MS score and was significantly different from RT alone. In conclusion, RT was not effective at improving the MS score; however, AT was effective. Combined AT and RT was similarly effective but not different from AT alone. When weighing the time commitment versus health benefit, the data suggest that AT alone was the most efficient mode of exercise for improving cardiometabolic health.

Effects of aerobic vs. resistance training on visceral and liver fat stores, liver enzymes, and insulin resistance by HOMA in overweight adults from STRRIDE AT/RT

While the benefits of exercise are clear, many unresolved issues surround the optimal exercise prescription. Many organizations recommend aerobic training (AT) and resistance training (RT), yet few studies have compared their effects alone or in combination. The purpose of this study, part of Studies Targeting Risk Reduction Interventions Through Defined Exercise-Aerobic Training and/or Resistance Training (STRRIDE/AT/RT), was to compare the effects of AT, RT, and the full combination (AT/RT) on central ectopic fat, liver enzymes, and fasting insulin resistance [homeostatic model assessment (HOMA)]. In a randomized trial, 249 subjects [18-70 yr old, overweight, sedentary, with moderate dyslipidemia (LDL cholesterol 130-190 mg/dl or HDL cholesterol ≤ 40 mg/dl for men or ≤ 45 mg/dl for women)] performed an initial 4-mo run-in period. Of these, 196 finished the run-in and were randomized into one of the following 8-mo exercise-training groups: 1) RT, which comprised 3 days/wk, 8 exercises, 3 sets/exercise, 8-12 repetitions/set, 2) AT, which was equivalent to ∼19.2 km/wk (12 miles/wk) at 75% peak O(2) uptake, and 3) full AT + full RT (AT/RT), with 155 subjects completing the intervention. The primary outcome variables were as follows: visceral and liver fat via CT, plasma liver enzymes, and HOMA. AT led to significant reductions in liver fat, visceral fat, alanine aminotransferase, HOMA, and total and subcutaneous abdominal fat (all P < 0.05). RT resulted in a decrease in subcutaneous abdominal fat (P < 0.05) but did not significantly improve the other variables. AT was more effective than RT at improving visceral fat, liver-to-spleen ratio, and total abdominal fat (all P < 0.05) and trended toward a greater reduction in liver fat score (P < 0.10). The effects of AT/RT were statistically indistinguishable from the effects of AT. These data show that, for overweight and obese individuals who want to reduce measures of visceral fat and fatty liver infiltration and improve HOMA and alanine aminotransferase, a moderate amount of aerobic exercise is the most time-efficient and effective exercise mode.

Minimal versus umbilical waist circumference measures as indicators of cardiovascular disease risk.

Objective: Measures of central obesity are strongly correlated with cardiovascular disease (CVD) risk. Although waist circumference (WC) is a commonly used measure of central obesity, there is no standard measurement location. We examined two WC locations to determine which was more highly correlated with CVD risk factors and metabolic syndrome (MS).

Effects of exercise training amount on physical activity energy expenditure.

INTRODUCTION We examined the effects of three exercise training interventions on total physical activity energy expenditure (PAEE) or nonexercise PAEE in a randomized controlled trial where sedentary, overweight, and obese men and women were assigned to inactive control, low-amount/moderate-intensity, low-amount/vigorous-intensity, or high-amount/vigorous-intensity aerobic exercise. METHODS To measure PAEE, triaxial RT3 accelerometers were worn by subjects for 7 d at the beginning and end of an 8-month exercise intervention. In total, 50 subjects (control, n = 8; two low-amount groups, n = 28; high-amount group, n = 14) had usable PAEE data collected at both time points. RESULTS At baseline, subjects had an average age of 53.2 yr, had a body mass index of 29.7 kg x m(-2), and a relative peak VO2 of 28.7 mL x kg(-1) x min(-1). There were no significant differences between groups at baseline. After the intervention, average change in total PAEE was 8.4 +/- 20.9 kJ x h(-1) for controls, 58.6 +/- 20.9 kJ x h(-1) for the two low-amount groups, and 138.1 +/- 33.5 kJ x h(-1) for the high-amount group (means +/- SE). The high-amount group experienced a significantly greater increase in total PAEE compared with the controls (P = 0.02). As expected, total PAEE increased with increasing exercise volume. Average change in nonexercise PAEE was 8.4 +/- 20.9 kJ x h(-1) for control, 25.1 +/- 20.9 kJ x h(-1) for the low-amount groups combined, and 62.8 +/- 29.3 kJ x h(-1) for the high-amount group. There was no statistically significant difference in change of nonexercise PAEE among groups. CONCLUSIONS We conclude that in middle-aged overweight or obese subjects participating in an extended exercise intervention, total PAEE increased, and there was no compensatory decrease in nonexercise PAEE.

Effects of an 8-month exercise training program on off-exercise physical activity.

PURPOSE An active lifestyle is widely recognized as having a beneficial effect on cardiovascular health. However, no clear consensus exists as to whether exercise training increases overall physical activity energy expenditure (PAEE) or whether individuals participating in regular exercise compensate by reducing their off-exercise physical activity. The purpose of this study was to evaluate changes in PAEE in response to aerobic training (AT), resistance training (RT), or combined aerobic and resistance training (AT/RT). METHODS Data are from 82 participants in the Studies of Targeted Risk Reduction Interventions through Defined Exercise-Aerobic Training versus Resistance Training study, a randomized trial of overweight (body mass index = 25-35 kg·m(-2)) adults, in which participants were randomized to receive 8 months of AT, RT, or AT/RT. All subjects completed a 4-month control period before randomization. PAEE was measured using triaxial RT3 accelerometers, which subjects wore for a 5- to 7-d period before and after the exercise intervention. Data reduction was performed with a previously published computer-based algorithm. RESULTS There was no significant change in off-exercise PAEE in any of the exercise training groups. We observed a significant increase in total PAEE that included the exercise training, in both AT and AT/RT but not in RT. CONCLUSIONS Eight months of exercise training was not associated with a compensatory reduction in off-exercise physical activity, regardless of exercise modality. The absence of compensation is particularly notable for AT/RT subjects, who performed a larger volume of exercise than did AT or RT subjects. We believe that the extended duration of our exercise training program was the key factor in allowing subjects to reach a new steady-state level of physical activity within their daily lives.

Aerobic and resistance training effects on energy intake: the STRRIDE-AT/RT study.

PURPOSE Our study characterizes food and energy intake responses to long-term aerobic training (AT) and resistance training (RT) during a controlled 8-month trial. METHODS In the STRRIDE-AT/RT trial, overweight/obese sedentary dyslipidemic men and women were randomized to AT (n = 39), RT (n = 38), or a combined treatment (AT/RT, n = 40) without any advice to change their food intakes. Quantitative food intake assessments and food frequency questionnaires were collected at baseline (before training) and after 8 months of training (end of training); body mass (BM) and fat-free mass (FFM) were also assessed. RESULTS In AT and AT/RT, respectively, meaningful decreases in reported energy intake (REI) (-217 and -202 kcal, P < 0.001) and in intakes of fat (-14.9 and -14.9 g, P < 0.001, P = 0.004), protein (-8.3 and -10.7 g, P = 0.002, P < 0.001), and carbohydrate (-28.1 and -14.7 g, P = 0.001, P = 0.030) were found by food frequency questionnaires. REI relative to FFM decreased (P < 0.001 and P = 0.002), as did intakes of fat (-0.2 and -0.3 g, P = 0.003 and P = 0.014) and protein (-0.1 and -0.2 g, P = 0.005 and P < 0.001) in AT and AT/RT and carbohydrate (-0.5 g, P < 0.003) in AT only. For RT, REI by quantitative daily dietary intake decreased (-3.0 kcal.kg(-1) FFM, P = 0.046), as did fat intake (-0.2 g, P = 0.033). BM decreased in AT (-1.3 kg, P = 0.006) and AT/RT (-1.5 kg, P = 0.001) but was unchanged (0.6 kg, P = 0.176) in RT. CONCLUSIONS Previously sedentary subjects completing 8 months of AT or AT/RT reduced their intakes of calories and macronutrients and BM. In RT, fat intakes and REI (when expressed per FFM) decreased, BM was unchanged, and FFM increased.

Association of the Composite Inflammatory Biomarker GlycA, with Exercise-Induced Changes in Body Habitus in Men and Women with Prediabetes

GlycA is a new composite measure of systemic inflammation and a predictor of many inflammatory diseases. GlycA is the nuclear magnetic resonance spectroscopy-derived signal arising from glucosamine residues on acute-phase proteins. This study aimed to evaluate how exercise-based lifestyle interventions modulate GlycA in persons at risk for type 2 diabetes. GlycA, fitness, and body habitus were measured in 169 sedentary adults (45–75 years) with prediabetes randomly assigned to one of four six-month exercise-based lifestyle interventions. Interventions included exercise prescription based on the amount (energy expenditure (kcal/kg weight/week (KKW)) and intensity (%VO2peak). The groups were (1) low-amount/moderate-intensity (10KKW/50%) exercise; (2) high-amount/moderate-intensity (16KKW/50%) exercise; (3) high-amount/vigorous-intensity (16KKW/75%) exercise; and (4) a Clinical Lifestyle (combined diet plus low-amount/moderate-intensity exercise) intervention. Six months of exercise training and/or diet-reduced GlycA (mean Δ: −6.8 ± 29.2 μmol/L; p = 0.006) and increased VO2peak (mean Δ: 1.98 ± 2.6 mL/kg/min; p < 0.001). Further, visceral (mean Δ: −21.1 ± 36.6 cm2) and subcutaneous fat (mean Δ: −24.3 ± 41.0 cm2) were reduced, while liver density (mean Δ: +2.3 ± 6.5HU) increased, all p < 0.001. When including individuals in all four interventions, GlycA reductions were associated with reductions in visceral adiposity (p < 0.03). Exercise-based lifestyle interventions reduced GlycA concentrations through mechanisms related to exercise-induced modulations of visceral adiposity. This trial is registered with Clinical Trial Registration Number NCT00962962.