The rate of VO2 max decline with inactivity depends on training status; well-trained individuals lose capacity faster than untrained individuals but retain structural adaptations longer.

“it depends where you're starting though like it's like if if you're if you're well trained for a short period of time you'll lose it quickly if you're if you haven't been training then resting doesn't make any difference and if you're well trained for a long long period of time then you have structural adaptations that are going to take a lot longer to disappear”