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

Abstract

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 Յ40 mg/dl for men or Յ45 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 ϳ19.2 km/wk (12 miles/wk) at 75% peak O2 uptake, and 3) full AT ϩ 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 Ͻ 0.05). RT resulted in a decrease in subcutaneous abdominal fat (P Ͻ 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 Ͻ 0.05) and trended toward a greater reduction in liver fat score (P Ͻ 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 training; liver fat; resistance training; weight lifting; homeostasis model assessment WHILE THE BENEFITS OF BEING physically active are clear, many unresolved issues surround the optimal exercise prescription for these benefits. Many organizations recommend both aerobic training (AT) and resistance training (RT) for all adults. However, these recommendations are mainly based on the evaluation of each modality separately, as few studies have investigated the effects of combined AT and RT regimens compared with each modality individually. Furthermore, adherence to exercise recommendations of physicians is notoriously poor, and many patients cite lack of time as a reason for noncompliance. Understanding the effects of AT and RT is of critical importance if we are to apply evidence-based approaches to exercise recommendations to a wide population.Visceral fat and liver fat are associated with type 2 diabetes, metaboli...

Developing a new treatment paradigm for disease prevention and healthy aging

“…Further, such brief training would allow an entire session that also includes RT to only require about 45 min. It is important to note that recent studies such as STRRIDE AT/RT [57][58][59], while showing superior effects for long duration AT vs. RT on ectopic fat, may have found (as the authors noted) an effect from caloric expenditure and deficit that in a new multiple health behavior protocol would be produced from PA and quality nutrition without extended AT.…”

A Combined and Intensive Exercise Model Improves Physical Capacity in Cardiac Patients

“…Some studies have reported elevated HDL after endurance training [52]. Many of the participants in the present study used statins, which makes it difficult to interpret data on lipids.…”

The benefits of exercise for patients with non-alcoholic fatty liver disease

“…These differences include the use of circuit-based training (which has a concurrent 'aerobic' exercise stimulus) [19,22], the use of home-based prescription [17], and variation in training intensities and study populations, all of which combined limit the ability to generalize findings and draw practical conclusions. The largest study to date which has directly compared aerobic exercise with PRT observed significant reduction in liver fat score (assessed via attenuation of computed tomography) with 8 months of aerobic exercise training but not with PRT in overweight adults [20]. Moreover, despite performing double the training load of the aerobic alone or PRT alone groups, aerobic exercise combined with PRT led to a non-significant reduction in liver fat.…”

“…To date, there is sparse evidence for the efficacy of PRT as per these guidelines for liver fat reduction. Of the nine studies employing PRT in isolation, five observed a significant reduction in liver fat [5,13,[17][18][19], three of which conformed with the abovementioned guidelines [5,13,18], while four showed no benefit [12,[20][21][22] with discrepancies in outcomes likely due to the large heterogeneity in study design. These differences include the use of circuit-based training (which has a concurrent 'aerobic' exercise stimulus) [19,22], the use of home-based prescription [17], and variation in training intensities and study populations, all of which combined limit the ability to generalize findings and draw practical conclusions.…”