To the best of our knowledge, this is the first study to examine the effects of surgical mask use during submaximal exercise on walking distance and physiological responses in children with CP. Our study showed that the walking distance decreased significantly with a surgical mask in children with CP. However, physiological responses were similar when masked and unmasked walking were compared.
Due to reduced physical activity opportunities as a result of the pandemic, children with cerebral palsy are likely to have reduced walking endurance. In our study, unmasked 6-MWT distances were approximately 100 meters shorter than the pre-pandemic literature [23, 24]. The current study was carried out during the pandemic period. Closing schools and rehabilitation centers and restricting leisure activities [25] during this period may have negatively affected their physical activity level and endurance [26]. It can be posited that the functional cardiorespiratory capacity of children with cerebral palsy decreased during the pandemic period. It can be considered that children with cerebral palsy may be more sensitive to physical activity with a mask.
The masked walking distance was significantly shorter than the unmasked walking distance in our study. This difference may be explained by increased perceived effort or discomfort during masked walking [27, 28]. Furthermore, using a surgical mask increases the resistance encountered during inspiration and expiration [29]. The increased perceived exertion and inspiratory and expiratory resistance may have contributed to reduced walking distance with masks in children with CP. In contrast, the existing literature indicates no significant reduction in submaximal exercise capacity with wearing a surgical mask in typically developing children [27]. The divergent outcomes observed between typical children and those with CP may be attributed to the reduced cardiorespiratory and musculoskeletal fitness in children with CP. Children with CP exhibit a reduced cardiorespiratory capacity and a higher respiratory rate and surface ventilation when compared to typically developing children [30]. Children with CP are at an increased risk of developing musculoskeletal disorders, including contractures, atypical postures, balance problems, and misalignments. These findings have been well documented to be associated with low gait performance and require high energy expenditure [31, 32]. The decreased performance of children with CP during submaximal masked exercise can be attributed to these specific characteristics of these children.
Our study found no significant differences in oxygen saturation, heart rate, and respiratory frequency between masked and unmasked walking. Consistent with our research, the literature shows that physiological responses do not change significantly during submaximal masked exercise. The use of face masks during moderate to vigorous physical activity in healthy children has a small and physiologically tolerable effect on respiratory and hemodynamic parameters [33, 34]. The ventilation was physiologically managed using feedback loops. A decrease in partial oxygen pressure increases heart rate and minute ventilation [35]. This theoretical information suggests that using a mask may increase the volume of carbon dioxide, which in turn may increase hemodynamic indicators. However, the existing literature on typically developing children and our study indicated that the physiological responses during submaximal physical exertion with a mask did not change significantly or in a clinically meaningful way [36]. It is important to note that there is evidence from some studies indicating that the use of N95 and surgical masks at increased exertion can result in changes to cardiac and respiratory parameters. However, these changes are within the safety range of [37, 38].
Our study has some limitations. The nature of our research makes it challenging to objectively assess oxygen consumption when wearing a mask, as the mask must be worn over the mask itself. If we had also measured perceived exertion and dyspnea in our study, we could have more comprehensively discussed the decrease in the 6-MWT distance. Although the post-power test indicated that our sample group was sufficient, our case number was limited for the complete representation of the sub-dimensions of CP. We measured oxygen saturation, respiratory frequency, and heart rate before and after submaximal activity. Further studies suggest that these data be measured during activity as well. Since we did not know the participants' physical activity levels, it was impossible to discuss the effect of mask use on submaximal activity in active and sedentary children with CP. We recommend evaluating children's physical activity levels in future studies.