Research published here: https://www.aging-us.com/article/202188/text

"The protocol comprised of 60 daily sessions, five sessions per week within a three-month period. Each session included breathing 100% oxygen by mask at 2ATA for 90 minutes with 5-minute air breaks every 20 minutes."

Notably small number of participants in the study. Still, this seems like it would be a big deal if the results can be reproduced.