## 4 Discussion  
The aim of this study was to examine the effect of a single session of aerobic exercises or bal&coor exercises on higher cognitive functioning in comparison to a single session of journal reading. The main findings show a positive effect of such exercise on attention in older adults, compared to a sitting and reading control task. Attention was assessed based on the ability to inhibit a response to read a word and activate a weaker response to name the color of the ink in which the word appeared (RT for the Go-NoGo test and RT at the no-interference phase of the Stroop test). The results of the positive effect of aerobic exercise on attention are in line with previous studies. Chronic aerobic exercise was associated with potent structural and functional neuroplastic changes and improved cognitive functions [23]. Acute aerobic exercise is associated with enhancing several neurotransmitter systems afferent to the hippocampus, which are essential to hippocampal function [24] and have been found to be related to improved cognitive functions, especially prefrontal cortex-dependent cognition, such as working memory and cognitive flexibility [23]. While the positive effect on attention is already well established for aerobic exercises [10; 11; 12], the positive effect of bal&coor found in the current study is unique. In several studies, mind-body exercises (i.e., Tai Chi, Qigong, Yoga, and Pilates), which involve a variety of actions, such as the stretching and relaxation of skeletal muscles, as well as coordinated body and regular breathing movements, were found to moderately improve cognitive functions. The researchers suggested that the meditative states involved in mind-body exercise regulate attention and consciousness, thus improving functions that demand attention [6]. As such, it may be possible that the exercises that were practiced in the current study during the bal&coor session made participants focus their attention on specific targets (i.e., controlling balance while standing on one leg and focusing their eyes on a bouncing ball), thereby leading to increased attentional levels. It is also possible that the complexity of the tasks that the participants performed during this session and the related involvement of cognitive functions led to improved attention functions [25]. Regarding the effect of exercise on executive function, no differences were found in the current study between aerobic, balance, and coordination exercises or reading a journal. All those interventions led to a significant improvement compared to the baseline assessment. This result stands in opposition to results about the beneficial effect of aerobic exercise upon control intervention in healthy older adults [6; 10; 15; 26]. It is possible that the intensity that was practiced in the current study during both aerobic as well as bal&coor exercises did not reach the optimal threshold for improvement in the domain of executive function [15]. In addition, it is possible that the bal&coor exercise, although based on cognitively challenging movements, was performed only once (as a single session) and thus did not reach the neural stimulation needed for induced cognitive changes [27]. Futurestudies should assess the effect of different bal&coor exercise intensities and durations on executive function in older adults. An exciting result that emerged in the study refers to the phenomenon of different behavior groups responding to different types of intervention. More specifically, some of the participants showed significantly higher cognitive scorers following aerobic exercise (seven participants for both ATT and EF), while others showed significantly higher cognitive scorers following bal&coor exercise (eight participants), and one participant showed significantly higher cognitive scorers following the control (reading a journal) condition.