Investigation of continuous and interval exercises effects on cognitive functions, risk taking, working memory and attention, using cognitive tests and functional near infrared spectroscopy.

Objective: Along with the more sedantary lifestyle, regular physical activity has become even more important for prevention from chronic diseases and for a healthy life. It is known that exercise contributes positively to mental functions as well as physical functions. In this context, understanding of efficient methods for whole body health has become important in the choice of exercise. We aimed to find the effects of continuous and intermittent exercise methods on cognitive functions under anaerobic threshold and the relationship with prefrontal oxygenation. Method: In our study, intermittent and continuous exercise was performed on different days by high trained sportsmen . In the continuous exercise, 20 minutes of constantly loaded exercise with power output equivalent to 90% of the respiratory anaerobic threshold load,and in the intermittent exercise 4 sets of 5 minutes of exercise at the same load and 2 minutes of 50-watt loaded rest exercise were performed . Stroop, PASAT and BART tests were performed to evaluate cognitive functions before and after each exercise session. Prefrontal oxygenation levels were measured with Functional Near Infrared Spectroscopy (fNIRS) throughout this period. Cortical levels of blood and saliva were measured before and after exercises to be able to see the effect of stress. Results: In our study, the level of difficulty perceived in continuous exercise was found to be higher than intermittent exercise (p <0,05). When the BART risk taking test was evaluated, it was seen that the risk taking tendency increased after continuous exercise (p <0,05). There was no difference between the exercises in the PASAT test (p> 0,05). Stroop interference was increased after continuous exercise (p <0,05), but there was no significant difference after intermittent exercise compared to before. There was no difference in prefrontal cortex oxygenation levels among exercise types. During the Stroop test, pre-exercise behavioral test results at each type of the exercise and prefrontal cortex oxyhemoglobin levels were highly correlated (r = .79-.88). There was a high negative correlation between the number of correct responses in intermittent exercise PASAT behavioral test and prefrontal cortex oxyhemoglobin levels (r = .71). There was no significant correlation between BART behavioral test and prefrontal oxyhemoglobin levels. Conclusion: In anaerobic subthreshold continuous exercise, deterioration of cognitive functions and increase of risk tendency were observed. With these findings intermittent exercise was thought to be a more efficient method in terms of cognitive functions. There was no difference in exercise methods in terms of prefrontal oxygenation but prefrontal oxygenation was found to increase as the deterioration in cognitive functions increased. Key words: continuous exercise, intermittent exercise, cognitive function, Stroop, PASAT, BART, fNIRS