The ongoing COVID-19 pandemic requires wearing face masks in many areas of our daily life; hence, the potential side effects of mask use are discussed. Therefore, the present study explores whether wearing a medical face mask (MedMask) affects physical working capacity (PWC). Secondary, the influence of a filtering facepiece mask with exhalation valve class 2 (FFP2exhal) and a cotton fabric mask (community mask) on PWC was also investigated. Furthermore, corresponding physiological and subjective responses when wearing face masks as well as a potential moderating role of subjects’ individual cardiorespiratory fitness and sex on face mask effects were analyzed. Thirty-nine subjects (20 males, 19 females) with different cardiorespiratory fitness levels participated in a standardized submaximal bicycle ergometer protocol using either a MedMask, FFP2exhal, community mask, or no mask (control) on four days, in randomized order. PWC130 and PWC150 as the mechanical load at the heart rates of 130 and 150 beats per minute were measured as well as transcutaneous carbon dioxide partial pressure, saturation of peripheral capillary oxygen, breathing frequency, blood pressure, perceived respiratory effort, and physical exhaustion. Using the MedMask did not lead to changes in PWC or physiological response compared to control. Neither appeared changes exceeding normal ranges when the FFP2exhal or community mask was worn. Perceived respiratory effort was up to one point higher (zero-to-ten Likert scale) when using face masks (p < 0.05) compared to control. Sex and cardiorespiratory fitness were not factors influencing the effects of the masks. The results of the present study provide reason to believe that wearing face masks for infection prevention during the COVID-19 pandemic does not pose relevant additional physical demands on the user although some more respiratory effort is required.

IntroductionLaparoscopy has partially replaced open surgery due to the lower infection rate for the patient and hence better and shorter recovery. However, the surgeon’s physical load is higher due to longer duration static and awkward body postures, increasing the risk for developing work-related musculoskeletal disorders. Interventions of an organisational nature are work breaks, being either passive or active. The primary objectives of this study are to determine whether passive and active work breaks lead to less discomfort than no work breaks and whether active work breaks lead to less discomfort than passive work breaks.Methods and analysisA controlled, randomised cross-over trial will be performed in the laboratory, of which its protocol is described here according to the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) 2013 Statement. Recruitment of 21 laparoscopic surgeons started in April 2019 and the study is ongoing. The participating surgeons will perform three 1.5 hour experimental conditions, one without work breaks, one with 2.5 min passive work breaks including rest, and one with 2.5 min active work breaks including mobility and stretching exercises. The work breaks will be taken after 30 and 60 min of work. During the experiments, outcomes will be recorded. The primary outcome is rating of perceived discomfort measured on an 11-point numeric rating scale. The secondary outcomes are performance, muscle activity of selected muscles, upper body angles, heart rate, workload and subjective evaluation of both interventions. The collected data will be tested using a one-way or two-factorial repeated-measures analysis of variance.Ethics and disseminationEthical approval of the study protocol was received by the local medical ethical committee of the University of Tübingen in February 2019 (no 618/2018BO2). The results of this study will be presented at national and international conferences, submitted for publications in peer-reviewed journals and serve as the starting point for a feasibility study.Trial registration numberNCT03715816.

Objective Investigate the effect of passive, active or no intra-operative work breaks on static, median and peak muscular activity, muscular fatigue, upper body postures, heart rate, and heart rate variability. Background Although laparoscopic surgery is preferred over open surgery for the benefit of the patient, it puts the surgeons at higher risk for developing musculoskeletal disorders especially due to the less dynamic and awkward working posture. The organizational intervention intraoperative work break is a workplace strategy that has previously demonstrated positive effects in small-scale intervention studies. Methods Twenty-one surgeons were exposed to three 90-min conditions: no breaks, 2.5-min passive (standing rest) or active (targeted stretching and mobilization exercises) breaks after 30-min work blocks. Muscular activity and fatigue of back, shoulder and forearm muscles were assessed by surface electromyography; upper body posture, i.e., spinal curvature, by inclination sensors; and heart rate and variability (HRV) by electrocardiography. Generalized estimating equations were used for statistical analyses. This study (NCT03715816) was conducted from March 2019 to October 2020. Results The HRV-metric SDNN tended to be higher, but not statistically significantly, in the intervention conditions compared to the control condition. No statistically significant effects of both interventions were detected for muscular activity, joint angles or heart rate. Conclusion Intraoperative work breaks, whether passive or active, may counteract shoulder muscular fatigue and increase heart rate variability. This tendency may play a role in a reduced risk for developing work-related musculoskeletal disorders and acute physical stress responses.

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