Shahid Beheshti University of Medical Sciences The Scientific Journal of Rehabilitation Medicine 2251-8401 14 4 2025 09 23 Effects of Physical and Brain Activity Until Exhaustion on Heart Rate and Perceived Exertion of Fatigue in Females Effects of Physical and Brain Activity Until Exhaustion on Heart Rate and Perceived Exertion of Fatigue in Females 618 635 1101823 10.32598/SJRM.14.4.3355 FA Fatemesadat Mousavian Department of Motor Behavior Faculty of Sport Sciences, Alzahra University, Tehran, Iran. 0009-0006-9903-7488 Parvaneh Shamsipour Dehkordi Department of Motor Behavior Faculty of Sport Sciences, Alzahra University, Tehran, Iran. 0000-0001-7750-5734 Maryam Khalaji Department of Sports Coaching, Faculty of Sports and Health Sciences, University of Tehran, Tehran, Iran. 0009-0001-5445-5364 Journal Article 2025 04 18 <strong>Background and Aims</strong> Fatigue resulting from physical and cognitive activities is one of the fundamental challenges in sports sciences and neurosciences, which can affect an individual’s physical and psychological performance. The present study aims to compare the effects of physical activity and brain activity until exhaustion on heart rate (objective physiological response) and perceived exertion of fatigue (subjective response) in females.<br /><strong>Methods </strong>This is a quasi-experimental study on 20 female students aged 25-30 from Alzahra University, Tehran, Iran, who were selected using a purposive sampling method. They were divided into two groups: brain activity (n=10) and physical activity (n=10). The physical activity group performed the plank exercise for 15 minutes or more until reaching fatigue, while the brain activity group performed the Stroop task for 45 minutes. Borg’s Rating of Perceived Exertion Scale, Falstein et al.’s 10-item fatigue assessment scale, and a Polar heart rate monitor were used to collect data. Perceived exertion of physical and mental fatigue, and heart rate in each group were recorded before the activity, 5 and 10 minutes during the activity, immediately after, and five minutes after the end of the activity. <br /><strong>Results </strong>The results of repeated measures analysis of variance showed that the heart rate and perceived exertion of physical and mental fatigue in both groups increased with increasing duration of physical or mental exercises. The mean heart rate and perceived exertion of physical fatigue were significantly higher in the physical activity group than in the brain activity group in the fifth and tenth minutes during the activity, immediately after the end of the activity, and five minutes after the activity (P=0.001). The mean perceived exertion of mental fatigue was higher in the brain activity group than in the physical activity group in the fifth and tenth minutes during the activity, immediately after the end of the activity, and five minutes after the activity (P=0.001). <br /><strong>Conclusion </strong>Physical activity until exhaustion mainly increases the physiological load (heart rate) of females, while brain activity until exhaustion increases their cognitive load (perceived exertion of mental fatigue). These results can provide a scientific basis for optimizing training programs for women by balancing between physical and mental loads. Designing effective exercise protocols for women requires simultaneous attention to physical and mental dimensions of fatigue. This integrated approach not only prevents the occurrence of premature exhaustion but also significantly reduces the risk of exercise-induced injuries. <strong>Background and Aims</strong> Fatigue resulting from physical and cognitive activities is one of the fundamental challenges in sports sciences and neurosciences, which can affect an individual’s physical and psychological performance. The present study aims to compare the effects of physical activity and brain activity until exhaustion on heart rate (objective physiological response) and perceived exertion of fatigue (subjective response) in females.<br /><strong>Methods </strong>This is a quasi-experimental study on 20 female students aged 25-30 from Alzahra University, Tehran, Iran, who were selected using a purposive sampling method. They were divided into two groups: brain activity (n=10) and physical activity (n=10). The physical activity group performed the plank exercise for 15 minutes or more until reaching fatigue, while the brain activity group performed the Stroop task for 45 minutes. Borg’s Rating of Perceived Exertion Scale, Falstein et al.’s 10-item fatigue assessment scale, and a Polar heart rate monitor were used to collect data. Perceived exertion of physical and mental fatigue, and heart rate in each group were recorded before the activity, 5 and 10 minutes during the activity, immediately after, and five minutes after the end of the activity. <br /><strong>Results </strong>The results of repeated measures analysis of variance showed that the heart rate and perceived exertion of physical and mental fatigue in both groups increased with increasing duration of physical or mental exercises. The mean heart rate and perceived exertion of physical fatigue were significantly higher in the physical activity group than in the brain activity group in the fifth and tenth minutes during the activity, immediately after the end of the activity, and five minutes after the activity (P=0.001). The mean perceived exertion of mental fatigue was higher in the brain activity group than in the physical activity group in the fifth and tenth minutes during the activity, immediately after the end of the activity, and five minutes after the activity (P=0.001). <br /><strong>Conclusion </strong>Physical activity until exhaustion mainly increases the physiological load (heart rate) of females, while brain activity until exhaustion increases their cognitive load (perceived exertion of mental fatigue). These results can provide a scientific basis for optimizing training programs for women by balancing between physical and mental loads. Designing effective exercise protocols for women requires simultaneous attention to physical and mental dimensions of fatigue. This integrated approach not only prevents the occurrence of premature exhaustion but also significantly reduces the risk of exercise-induced injuries.