Differences in neurocognitive performance and metabolic and inflammatory indices in male adults with obesity as a function of regular exercise

Abstract

New findings: What is the central question of this study? Does regular exercise have benefits with regard to the neurocognitive problems related to obesity and are regular-exercise-induced neurocognitive changes associated with changes in the levels of metabolic/inflammatory biomarkers? What is the main finding and its importance? Although obese individuals with regular exercise showed higher C-reactive protein levels as compared to the healthy-weight individuals, only the obese individuals with a sedentary lifestyle showed deviant neurocognitive performance and higher metabolic and tumour necrosis factor-α levels. The P3 amplitude was correlated with the levels of leptin in the obese individuals with regular activity, implicating that the potential mechanism of neurocognitive facilitation as a result of regular exercise could be reduced serum leptin levels.

Abstract: Obesity has been shown to be highly associated with deterioration in executive functions, elevated energy metabolic indices and low-grade systemic inflammation. Exercise has the capacity to reduce these negative phenomena. This work examined the effect of regular exercise on neurocognitive deficits and metabolic/inflammatory markers in obesity. Fifty-four participants were divided into three groups: healthy-weight (HW), obesity with regular exercise (ORE) and obesity with sedentary lifestyle (OSL), according to their BMI and frequency of exercise. Dual-energy X-ray absorptiometry was applied to assess the whole-body composition of the participants. The assessment included neurocognitive measures during the Posner paradigm test and fasting blood measurements. Relative to the HW group, only the OSL group showed significantly longer reaction times and smaller P3 amplitudes, even when controlling for the cardiorespiratory fitness co-variable. Although the OSL group exhibited a greater N2 amplitude than the HW group, when controlling for cardiorespiratory fitness the difference between the two groups disappeared. The OSL group showed greater levels of metabolic indices (i.e. leptin, insulin and glucose) than the HW group. The three groups had comparable interleukin (IL)-1β and IL-6 levels. However, the ORE and OSL groups showed higher levels of C-reactive protein than the HW group. The OSL group exhibited higher tumour necrosis factor-α levels than the HW and ORE groups. P3 amplitude was negatively correlated with the levels of leptin in the ORE group. Individuals with obesity can still obtain advantages with regard to neurocognitive and metabolic/inflammatory indices through engaging in regular exercise, possibly due to reduced serum leptin levels.

Keywords: cognition; event-related potential; exercise; inflammatory cytokine; metabolic; obesity.