Effects of Resistance and Aerobic Exercise Training or Education Associated with a Dietetic Program on Visfatin Concentrations and Body Composition in Overweight and Obese Women

What is it about?

During the past few decades, the incidence of overweightness and obesity has reached epidemic levels, and at same time, there was are increases in numerous overweight/obesity-related diseases such as certain types of cancer, heart disease, and also diabetes (1). Weight loss via lifestyle modification is one of the suggested ways to treat or prevent these diseases (2). Typical weight loss related to lifestyle modification is around 5% - 10% of baseline weight, but it can bring health benefits (3). Although overweightness and obesity result from an imbalance between energy intake and expenditure, the pathophysiology of this condition (an imbalance between energy intake and expenditure) is best explained by an enlargement and/or increase in fat cells (4). This increase in adipose tissue, which as an active endocrine organ, is responsible for the secretion of various peptides called adipocytokines, which themselves play an important role in regulating energy reception and consumption (5). One such peptide is visfatin, which is primarily produced by visceral adipose tissue (and skeletal muscles, liver, bone marrow, and lymphocytes) and whose gene expression and plasma concentrations are found to be increased in obese individuals (6).

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Photo by AllGo - An App For Plus Size People on Unsplash

Photo by AllGo - An App For Plus Size People on Unsplash

Why is it important?

Visfatin is recognized as the formerly described Nicotinamide phosphoribosyltransferase (Nampt), and is a new adipokine which is a colony-stimulating factor activating the synthesis of pre-beta cells isolated from lymphocytes (7, 8). At present, it is speculated that visfatin alters fat metabolism either directly or indirectly (9). Support for the role of visfatin in the development of overweightness and obesity arises from those studies that demonstrate increased visfatin concentrations in overweight and obese individuals (10, 11). In addition, these elevated visfatin concentrations and its gene expression in fat cells in obese individuals provides convincing evidence of the relationship of visfatin with visceral fat mass and body mass index (12). However, the research pertaining to the effects of exercise on plasma visfatin concentrations are not yet conclusive, and some contradictory results have been found. While it has been demonstrated that visfatin increases after the first phase of exhaustive aerobic exercise, and remains high for 24 hours following the exercise bout (13), a reduction of plasma visfatin levels or even the absence of change in visfatin levels following aerobic exercise have also been reported (14). In spite of the majority of published results having utilized only aerobic training in their protocols, data from recent studies suggests that resistance training may be an effective alternative to aerobic training for improving body composition in obese individuals (10, 15), since resistance training has been shown to preferentially reduce visceral and subcutaneous tissue in the abdominal region (10). Further, previous studies may indicate a possibility that a combination of both aerobic and resistance training may reduce visfatin even more than either aerobic or resistance training alone due to superior improvements in body composition, especially abdominal fat (10), and even superior improvements in self-reported dietary restriction, above those of these sole modes of exercise training (16). Recently, some studies have suggested that plasma visfatin is reduced after aerobic exercise training in sedentary, older, obese men and women (17). In addition, Mehdizadeh et al. (2016) demonstrated that their aerobic exercise group displayed more improvements in their weight, body fat percentage (BF%) and the waist-to-hip ratio (WHR) indices than resistance training participants. Moreover, the combined exercise training (aerobic-resistance) was more effective than the aerobic exercise in the improvement of BF%, but visfatin levels decreased equally in both aerobic and combined (aerobic-resistance) groups (18). However, the changes observed in body composition, and thus possibly visfatin, following resistance training may be due to the type of resistance training that an individual engages in (19). As such, this study was constructed to evaluate and compare the effects of resistance training (RT), concurrent resistance and aerobic training (RT + AT) and education-only (EDU) on plasma visfatin concentrations and body composition in overweight and obese women. We hypothesized that an eight-week RT or RT + AT can improve visfatin levels and body composition in overweight and obese women, with superior improvements arising from the concurrent training (i.e. RT + AT).

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