Ok, here's what I really think. I stopped paying registration fees when I was 45. I think it's the story of carrying the calf every day and as it grows into a bull, you'll have the muscles of an ox or Paul Bunyan or whatever. If you started nursing young, continued working, lifted weights, maintained your girlhood figure and have postmenopausal jest, go for it. During WWII, Britain said the postmenopausal nurse could work circles around the young nurses.
But to be honest, I thought I was going to die of exhaustion at 33 when I was pregnant and had 3 preschoolers who never seemed to be asleep at the same time and I had a work crew of prisoners helping me watch the kids. So if I had to decide who needed all the special accommodations, I would look at a whole cluster of things.
All those 40 something actresses who said they were very young 40s in excellent condition found that their ovaries thought otherwise. I was born matronly and out of condition so it was a no brainer for me to decide that it was in the best interests of everyone for me to remove myself from the College of Nurses list of RNs. And if I'm a patient lying in a hospital bed and my heart stops, I don't care what the age of the nurse is - I want the one that can sprint down the hall the fastest, get a bedboard under me, hop up on the bed and do CPR the longest. I don't want to be the nurse who has a heart attack herself in the midst of that dramatic situation and divides the focus of the crash team.