Effects of obesity phenotype on fat metabolism in obese men during endurance exercise

Abstract

Objective: The effects of obesity phenotype on fat metabolism during endurance exercise are unclear. This study aimed to investigate in obese men whether body fat distribution would influence plasma fat availability and oxidation during endurance exercise. Design: Fourteen sedentary men (body mass index (BMI)425 kg/m 2 ) were divided into two groups by visceral fat (VF) area: VF obese (VF-Ob) (n ¼ 7, age; 52.072.5 (s.e.) years) and abdominal subcutaneous fat obese (SF-Ob) (n ¼ 7, age; 57.372.8 (s.e.) years). All participants performed stationary cycling exercise for 60 min at 50% of peak oxygen uptake. Measurements: Blood and respiratory gas samples were taken for analysis of hormone, metabolite and substrate oxidation in each participant at rest and during exercise. Results: There is a significant group  time interaction in the plasma concentration of free fatty acid (FFA) (Po0.05) and glycerol (Po0.05) during the exercise bout. In addition, total plasma concentration of FFA (area under the curve) was 59.2% higher in VF-Ob compared with SF-Ob men during endurance exercise (1.9970.24 and 1.2570.13 mEq/l/min, respectively; Po0.05). Total plasma concentration of glycerol (area under the curve) was 102.3% higher in VF-Ob than SF-Ob men during the exercise (69.6712.5 and 34.475.1 mg/dl/min, respectively; Po0.05). However, fat oxidation was not different throughout the exercise between VF-Ob and SF-Ob men (176.5725.7 and 183.0712.8 kcal/60 min, respectively). Conclusion: During moderate endurance exercise, plasma fat availability may be higher in men with VF obesity compared to men with SF obesity. However, total fat oxidation is similar between obesity phenotype.

Sex differences in substrate oxidation during aerobic exercise in obese men and postmenopausal obese women

“…In the present study, the men and women differed in visceral fat and subcutaneous fat areas and in waist-to-hip ratio; however, these variables did not correlate with fat oxidation adjusted for FFM and average RER during aerobic exercise (data not shown). In this regard, our findings are therefore consistent with the results of previous studies [40][41][42][43].…”

“…Previous studies have found that abdominal fat distribution does not influence substrate oxidation during exercise in subjects of the same sex [40][41][42][43]. In the present study, the men and women differed in visceral fat and subcutaneous fat areas and in waist-to-hip ratio; however, these variables did not correlate with fat oxidation adjusted for FFM and average RER during aerobic exercise (data not shown).…”

Obesity phenotype and intra-abdominal fat responses to regular aerobic exercise

“…On the other hand, IF tissue has lower antilipolytic responses to insulin compared to SF tissue [33], which gradually decreases during prolonged exercise. A previous report [16] indicated higher lipid concentrations in HIF 245 obesity than MIF obesity in men. However, whole-body fat oxidation did not differ between HIF and MIF obesity phenotypes.…”

“…It has 45 been suggested that potential influencing factors include physiological, environmental and genetic attributes. Obesity phenotype is a possible factor influencing IF responses to regular aerobic exercise because of increased fat availability during a single bout of prolonged aerobic exercise in IF type obesity [16]. One study examined whether obesity phenotype would affect the IF response to a weight-loss intervention in 50…”

An arginine, alanine, and phenylalanine mixture increases synthesis of ketone bodies during low-intensity exercise via stimulating glucagon secretion in men with obesity

“…In particular, the blood levels of several hormones such as catecholamines, glucagon, growth hormone and cortisol are increased by acute exercise 6) . Moreover, several studies reported on acute exercise and lipid utilization, and related hormones in obese subjects [7][8][9] . Therefore, we hypothesize that a combination of acute exercise and the factors that affect the secretion of some of these hormones may be effective for increasing fat catabolism.…”