# The Effect of Surgical Mask Use in Anaerobic Running Performance
## 4 Discussion
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c} \hline \hline  & \multicolumn{4}{c}{**Basal Test**} & \multicolumn{4}{c}{**50 m Test**} & \multicolumn{4}{c}{**400 m Test**} \\ \cline{2-13}  & \multicolumn{2}{c}{**No Mask**} & \multicolumn{2}{c}{**Mask**} & \multicolumn{2}{c}{**No Mask**} & \multicolumn{2}{c}{**Mask**} & \multicolumn{2}{c}{**No Mask**} & \multicolumn{2}{c}{**Mask**} & \multicolumn{2}{c}{**Mask and Test Effect**} \\ \cline{2-13}  & **M** & **SD** & **M** & **SD** & **M** & **SD** & **M** & **SD** & **M** & **SD** & **M** & **SD** & **F** & \(p\) & \(\mathbf{\eta^{2}}\) \\ \hline \multirow{3}{*}{SD1 (ms)} & 16.3 & 15.0 & \multirow{3}{*}{4.54} & 15.0 & 6.89 & 9.02 & \multirow{3}{*}{4.56} & 9.02 & \multirow{3}{*}{3.42} & 5.90 & \multirow{3}{*}{3.61} & \multirow{3}{*}{4.11} & \multirow{3}{*}{0.017} & \multirow{3}{*}{0.033} \\  & **11.1** & & & & & & & & & & & & & & & \\  & **11.1** & & & & & & & & & & & & & & \\  & **11.1** & & & & & & & & & & & & & & \\ \hline \multirow{3}{*}{SD2 (ms)} & 41.9 & \multirow{3}{*}{14.7} & 42.2 & \multirow{3}{*}{9.49} & 42.2 & \multirow{3}{*}{23.2} & 31.8 & \multirow{3}{*}{20.6} & 10.2 & \multirow{3}{*}{7.59} & 12.4 & \multirow{3}{*}{8.67} & \multirow{3}{*}{0.436} & 0.612 & 0.004 \\  & **11.1** & & & & & & & & & & & & & \\  & **11.1** & & & & & & & & & & & & & \\ \hline \multirow{3}{*}{M: Mean. SD: Standard Deviation. F: Fisher-Snedecort test. \(\eta^{2}\): Partial eta squared. SDNN: Standard deviation of normal-to-normal R-R intervals. RMSSD: Square root of the mean of the sum of the squared differences between adjacent normal R-R intervals. pNN50: The percentage of differences between R-R intervals higher than 50 ms. LF: Low frequency. HF: High frequency. n.u.: Normalised unit. SD1: Poincaré Plot index of instantaneous recording of the variability. SD2: Poincaré plot index of overall variability. \(\ddagger\) Difference with basal test (\(\varphi<0.05\)). \(\ddagger\) Difference with 50 m test (\(\varphi<0.05\)). \(\ddagger\) Difference with 400 m test (\(p<0.05\)). \(\ddagger\) Differences between no mask/mask groups (\(\varphi<0.05\)). \\ \hline \hline \end{tabular}
\end{table} 
Table 2: _Cont._tance training efforts while wearing a mask [30]. We also found a significantly higher subjective perceived stress using the mask. It is feasible, that the masks negatively impact the dynamics of perception and effort, especially during demanding high intensity exercises [24], suggesting that the associated perceived effort [31] and stress [32] are important key reasons for the observed impairment of physical performance. Regarding blood oxygen saturation, athletes with surgical mask presented lower values in both tests (50 m and 400 m). This lower blood oxygen saturation would be expected due to increased partial pressure of CO\({}_{2}\) at high exercise intensity, increased tidal volume, and an inadequate oxygen and carbon dioxide exchange due re-breathing enriching inhaled air with CO\({}_{2}\)[8]. Contrary to our results, authors did not find a blood oxygen saturation decrease with surgical masks, either during extenuated [33], vigorous [11] or steady exercise [34]. However, a key factor explaining the differences lies in the intensity and level of previous training. The authors chose a sample of subjects performing at their maximum in cycloergometer [11] until extenuation, at around 2.6 W/kg, values which suggest poorly physically active subjects, not athletes [35]. Furthermore, a recent review also suggests no blood oxygen saturation changes with the use of a surgical mask while exercising [12]. Yet, none of the studies included in the review were carried out at medium-light physical intensity or with an athlete population. However, our results would be in line with previous hypotheses and studies on trained athletes to extenuation [8]. According to heart rate values, no differences were found between wearing and not wearing surgical mask.