Lucy W. Piner

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.

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.

Effects of a 12-Week mHealth Program on Functional Capacity and Physical Activity in Patients With Peripheral Artery Disease

Supervised exercise is beneficial for peripheral artery disease (PAD) patients limited by intermittent claudication (IC). However, supervised exercise for PAD remains widely underutilized. Mobile health (mHealth) provides an intermediate solution between supervised and independent home-based exercise. The purpose of this study was to determine the effects on functional capacity and physical activity patterns of a 12-week mHealth program in PAD patients with IC. Twenty patients were randomized into usual care or a 12-week mHealth intervention consisting of patient education, smartphones, and physical activity trackers. Patient education was disseminated through smartphone and a daily exercise prescription was given based on steps per day. Primary outcomes were 12-week changes in peak VO2 and claudication onset time; and changes in physical activity measured by steps per/day and minutes of exercise per/week. mHealth patients significantly increased peak VO2 from 15.2 ± 4.3 to 18.0 ± 4.8 ml/kg/min (20.3 ± 26.4%; p ≤0.05), while usual care did not change from 14.3 ± 5.4 to 14.5 ± 5.7 ml/kg/min (1.0 ± 6.9%; NS). Comparison of these changes resulted in a significant difference between groups (p ≤0.05) for peak VO2. Claudication onset time significantly increased in mHealth (320 ± 226 to 525 ± 252 seconds; ≤ 0.05), while usual care demonstrated a worsening (252 ± 256 to 231 ± 196 seconds; NS). The comparison of these group changes resulted in a significant difference (p ≤0.05). Neither steps per day or minutes of activity reached significant differences between groups. In conclusion, a 12-week mHealth program in PAD patients with IC can improve peak VO2 and claudication onset time; and mHealth interventions represent a promising alternative therapy for those patients who cannot participate in supervised exercise.

Effects of a 12-week mHealth program on peak VO2 and physical activity patterns after completing cardiac rehabilitation: A randomized controlled trial

Background: Site‐based cardiac rehabilitation (CR) provides supervised exercise, education and motivation for patients. Graduates of CR have improved exercise tolerance. However, when participation in CR ceases, adherence to regular physical activity often declines, consequently leading to worsening risk factors and clinical events. Therefore, the purpose of this pilot study was to evaluate if a mHealth program could sustain the fitness and physical activity levels gained during CR. Methods and Results: A 12‐week mHealth program was implemented using physical activity trackers and health coaching. Twenty‐five patients were randomized into mHealth or usual care after completing CR. The combination of a 4.7 ± 13.8% increase in the mHealth and a 8.5 ± 11.5% decrease in the usual care group resulted in a difference between groups (P ≤ .05) for absolute peak VO2. Usual care decreased the amount of moderate‐low physical activity minutes per week (117 ± 78 vs 50 ± 53; P < .05) as well as moderate‐high (111 ± 87 vs 65 ± 64; P < .05). mHealth increased moderate‐high physical activity (138 ± 113 vs 159 ± 156; NS). The divergent changes between mHealth and usual care in moderate‐high physical activity minutes/week resulted in a difference between groups (21 ± 103 vs – 46 ± 36; P < .05). Conclusions: A 12‐week mHealth program of physical activity trackers and health coaching following CR graduation can sustain the gains in peak VO2 and physical activity achieved by site‐based CR.