Over the hill at 40?

Having read your article in the latest Management magazine and as one of those who were last month notified of the award of the professional qualifi-cation by NZIM I am prompted to give you my views on the above subject.
Whilst I have had the experience of working with tired managers over the age of 40 there are still plenty of managers over 40 who are every bit as energetic and dynamic as executives in their thirties. In fact I have an associate who is close to 65 whose energy and drive would put many half that age to shame and SHE operates three successful retail operations and has in recent times been known to party until 4 or 5 in the morning.
In my own case on reaching 40 my energy and appetite for running business soared. After 17 years of professional career working in central & local government I made the decision to leave and run my own business. This was not decision forced by any redundancy or restructuring but quite simply the realisation that if change was not taken then, it may never happen.
So for the 3 years prior to leaving my employment I undertook part time business studies and just prior to turning 40 purchased my first business and shortly therafter completed the NZ Certificate In Management. That was just over eight years ago. In that time I have established 3 retail operations. Having sold one off we retain the first one and the last one established.
In addition during last year I was spending 3 days week for the first 6 months of the year assisting our builder add 60 sq metres of garage and second floor of 90 sq metres to our home. I am an executive officer and volunteer firefighter in our local fire brigade which attends up to 200 calls per year so in addition to firefighting have management role in the brigade.
I am Director of our family company which established and owns 45 hectares of pine forest in the North Island.
My wife and I have two children aged 9 and 3.
Having just turned 48 I do not consider myself to be over the hill yet.
Regards
Glenn Williams MNZIM