If you’re 50, be (a bit) careful.
Your max may still be what it was when you were young, your heart’s ability to do it may not be as youthful. We’ve had a few heart attacks at work from fit, strong, vigorous cyclists in their 50s.
Latest one did Dragon, fast, following week, honing his climbing for the etape, collapsed at top of a hill outsprinting his mates. DOA, sadly. Keen cyclist all his life, looked in great condition. 58.
I look at it in the same way as you don’t red-line an old car. It’ll do it, but what are the consequences?