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Endurance exercise performance declines with age; however, there is little information on the mechanisms responsible, especially in women. We tested the hypothesis that this performance decline in women is associated with decreases in maximal O2 consumption (VO2max), blood lactate threshold (LT), and running economy (RE). We determined a 10-km race pace, VO2max, LT, and RE in 31 highly trained female runners aged 23-56 yr with similar relative (i.e., age-adjusted) competitive performances. Absolute 10-km race pace declined with age (r = -0.83). Both 10-km performance and age were correlated with VO2max (P < 0.05) and with the running velocity and O2 consumption at LT but not with RE. The runners then were divided into three age groups: group I (23-35 yr), group II (37-47 yr), and group III (49-56 yr). Stepwise regression analyses performed on subjects pooled from groups I and II and from groups II and III indicated that the majority (60%) of the variability in performance for runners aged 23-47 yr was explained by the running velocity at which LT occurred, whereas VO2max explained the majority (74%) of the variability for the runners aged 37-56 yr. We conclude that decreases in VO2max and running velocity at LT are the two physiological phenomena most closely associated with declines in 10-km performance with age in highly trained female runners. However, the contributions of these two mechanisms to the declines in performance are not uniform with advancing age.

Background: In the wake of the SARS-CoV-2 pandemic and unprecedented global demand, clinicians are struggling to source adequate access to personal protective equipment. Respirators can be in short supply, though are necessary to protect workers from SARS-CoV-2 exposure. Rapid decontamination and reuse of respirators may provide relief for the strained procurement situation. Method: In this study, we investigated the suitability of 70 C dry heat and microwavegenerated steam (MGS) for reprocessing of FFP2/N95-type respirators, and Type-II surgical face masks. Staphylococcus aureus was used as a surrogate as it is less susceptible than enveloped viruses to chemical and physical processes. Results: We observed >4 log 10 reductions in the viability of dry S. aureus treated by dry heat for 90 min at 70 C and >6 log 10 reductions by MGS for 90 s. After 3 reprocessing cycles, neither process was found to negatively impact the bacterial or NaCl filtration efficiency of the respirators that were tested. However, MGS was incompatible with Type-II surgical masks tested, as we confirmed that bacterial filtration capacity was completely lost following reprocessing. MGS was observed to be incompatible with some respirator types due to arcing observed around some types of metal nose clips and by loss of adhesion of clips to the mask. Conclusion: Considering the advantages and disadvantages of each approach, we propose a reprocessing personal protective equipment/face mask workflow for use in medical areas.

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