I've attached a report from the APTA that breaks out the results of their annual demographic survey. From this report, it appears that the distribution of ages is surprisingly uniform.
Though all these numbers should be taken with a grain of salt. It's only a survey, so it only reflects those people who chose to respond. And only people who are already members of the APTA were surveyed (as far as I can tell). Plenty of opportunity for biases to creep in.
As a gut check of these numbers you can cross reference them with this survey:
It seems that the ages are well-distributed here, too. Though this is a survey of many rehab professions (PT, PTA, ATC). So no perfect source of information, but I'm not seeing an indication that things are terribly skewed.
Mike -- I'm a second year non-traditional student who started PT school at 32. I'm far from the oldest person in the class and I remember having concerns about the longevity of my future career after hearing a number of stories that indicated burnout/injury were very real concerns.
Our primary ortho professor noted that none of his original classmates are still practicing. His explanation was that many people got into practice, discovered that they weren't really equipped to help people, got frustrated with their lack of success and ultimately bailed. Of course this was from a time when heat and ultrasound were cornerstones of PT, and you could get into the profession with a BA. It might be different now that we have decades of additional knowledge regarding how to help people. Also, since most new PTs are going to be carrying substantial debt, walking away may never be a simple option. Maybe these changes are what is reflected in the two surveys above?
Another concern with longevity is injury. Assisting with transfers day-in and day-out can take a tool on a body--particularly with the increasing prevalence of obesity in our society. But even if you don't work inpatient, regular manual work in an outpatient setting can slowly tear a person apart. We discuss the importance of body mechanics, but on a long enough timeline mistakes happen and mistakes can add up.
I'm not sure if these are some of the concerns driving your question about older PTs. But these are concerns that I have as an older student and a career changer. My hope is that by avoiding high risk environments and selecting treatment techniques that protect me--while also providing benefit to the patient--I'll be able to persist in this for some time. Anyway. Just some rambling thoughts on a Saturday morning.