Because of the Coronavirus (COVID-19) and due to strict laws to limit the spread of the virus, it has become necessary and for everyone to wear masks, but some people perform tasks that require high effort, especially those who work in the field of health care, so it may affect them to wear masks for long periods during the effort. Therefore,  The objective of this research  is to to find out the effect of wearing masks on work capacity. Work capacity will be measured by  heart rate and rating of perceived exertion (RPE). To achieve the purpose of this study, A total of ten students of Alfaisal University were recruited in the study. A two-way repeated measures design,was be conducted. The independent variables which were studied in this experiment were : 1) Mask  (with and without), 2)  intensity of the workload (low, medium, and high). The dependent factors for this study were: 1) Heart rate  2) Rating of perceived exertion. A randomized complete block design with factorial treatment combinations was utilized in this study. Each participant was considered as a block and performed the six experiments in random order. The results show that mask and intenisty of workload  have significantly effected  the heart rate  and precieved excersion. The study suggested  to increased the rest periods to overcome the fatique based on different workload during wearning the mask