Effects of acute aerobic exercise on a task-switching protocol and brain-derived neurotrophic factor concentrations in young adults with different levels of cardiorespiratory fitness.

What is the central question of this study? Neurocognitive functions can be enhanced by acute aerobic exercise, which could be associated with changes in serum brain-derived neurotrophic factor (BDNF) concentrations. We aimed to explore acute exercise-induced changes in BDNF concentrations, neuropsychological and neurophysiological performances when individuals with different levels of cardiorespiratory fitness performed a cognitive task. What is the main finding and its importance? Only young adults with higher cardiorespiratory fitness could attain switching cost and neurophysiological benefits via acute aerobic exercise. The mechanisms might be fitness dependent. Although acute aerobic exercise could enhance serum BDNF concentrations, changes in peripheral BDNF concentrations could not be the potential factor involved in the beneficial effects on neurocognitive performance. This study investigated the effects of acute aerobic exercise on neuropsychological and neurophysiological performances in young adults with different cardiorespiratory fitness levels when performing a task-switching protocol and explored the potential associations between acute aerobic exercise-induced changes in serum brain-derived neurotrophic factor (BDNF) concentrations and various neurocognitive outcomes. Sixty young adults were categorized into one control group (i.e. non-exercise-intervention; n = 20) and two exercise-intervention (EI) groups [i.e. higher (EIH , n = 20) and lower (EIL , n = 20) cardiorespiratory fitness] according to their maximal oxygen consumption. At baseline and after either an acute bout of 30 min of moderate-intensity aerobic exercise or a control period, the neuropsychological and neurophysiological performances and serum BDNF concentrations were measured when the participants performed a task-switching protocol involving executive control and greater demands on working memory. The results revealed that although acute aerobic exercise decreased reaction times across three (i.e. pure, switching and non-switching) conditions in both EI groups, only the EIH group showed a smaller switching cost and larger P3 amplitudes after acute exercise, supporting the view that the mechanisms of neural functioning that underlie the effects of such exercise may be fitness dependent. In addition, serum BDNF concentrations were elevated after acute exercise for both EI groups, but there were no significant correlations between the changes in BDNF concentrations and changes in neuropsychological and neurophysiological performances for either group, suggesting that serum BDNF could not be the potential factor involved in the beneficial effects on neuropsychological and neurophysiological performances seen in young adults after acute aerobic exercise.

Executive function and endocrinological responses to acute resistance exercise.

THIS STUDY HAD THE FOLLOWING TWO AIMS: First, to explore the effects of acute resistance exercise (RE, i.e., using exercise machines to contract and stretch muscles) on behavioral and electrophysiological performance when performing a cognitive task involving executive functioning in young male adults; Second, to investigate the potential biochemical mechanisms of such facilitative effects using two neurotrophic factors [i.e., growth hormone (GH) and insulin-like growth factor-1 (IGF-1)] and the cortisol levels elicited by such an exercise intervention mode with two different exercise intensities. Sixty young male adults were recruited and randomly assigned to a high-intensity (HI) exercise group, moderate-intensity (MI) exercise group, and non-exercise-intervention (NEI) group. Blood samples were taken, and the behavioral and electrophysiological indices were simultaneously measured when individuals performed a Go/No-Go task combined with the Erikson Flanker paradigm at baseline and after either an acute bout of 30 min of moderate- or high-intensity RE or a control period. The results showed that the acute RE could not only benefit the subjects' behavioral (i.e., RTs and accuracy) performance, as found in previous studies, but also increase the P3 amplitude. Although the serum GH and IGF-1 levels were significantly increased via moderate or high intensity RE in both the MI and HI groups, the increased serum levels of neurotrophic factors were significantly decreased about 20 min after exercise. In addition, such changes were not correlated with the changes in cognitive (i.e., behavioral and electrophysiological) performance. In contrast, the serum levels of cortisol in the HI and MI groups were significantly lower after acute RE, and the changes in cortisol levels were significantly associated with the changes in electrophysiological (i.e., P3 amplitude) performance. The findings suggest the beneficial effects of acute RE on executive functioning could be due to changes in arousal, possibly modulated by the serum cortisol levels.