No, I am not confused about the date, as maybe you wondered when you saw the title of this posting. I know it is still more than four months until the first day of winter according to the 2013 calendar. But I am writing about the seasons of life.

The Japanese make much of the four seasons. Often in Japan you see four paintings of the same scene in nature, but each in a different season. Sometimes, though, a person’s lifetime is said to have four seasons.

Traditionally, there seems to have been the idea that each season is 20 years long. There are special birthday remembrances for those who turn sixty, which would be the first day of winter if each season is twenty years.

Years ago I had a Japanese acquaintance who thought that each season should be 30 years long, so he talked about living to be 120. (I have lost touch with him, and I’m afraid he has already passed away, long before reaching 120.)

Still, maybe he was onto something. The cover of the May 2013 issue of “National Geographic” shows a young child, above whose picture are the words: “This Baby Will Live to be 120.” And a footnote says, “It’s not just hype. New science could lead to very long lives.”

But for me and maybe for all of you reading this, living until 120 is quite unlikely, and perhaps not even desirable. Realistically, four seasons of 25 years is perhaps all we can expect—and even at that most of us will likely not make it to the end of winter.

I am writing this because today, August 15, is my 75^th birthday, and I am thinking of this as being the first day of winter for me. Actually, I started thinking about this more than a year ago. And I thought I would probably make several lifestyle changes at the beginning of winter.

For example, I thought I would not sign up to teach any more university classes. And I thought I would quit jogging and just take long walks for exercise.

But during the past several months I changed my mind. I have agreed to start teaching my one class again at Rockhurst University next week. I am also going to keep on jogging two-miles a time, five days a week – at least for now.

Of course, health is a big factor in what one does. Illness greatly hampers a person’s activities regardless of age. But I have decided that as long as one is healthy there is no use ceasing to do what one enjoys doing, or what is good for you, because of an arbitrary date.

So I am going to keep on keeping on, enjoying winter, and enjoying being active, for as long as possible.

What about you? According to a Pew Research study released this month, “69% of American adults would like to live to be 79 to 100 years old.” But only 8% wanted to live past 100. So maybe four 25-year seasons is a good way to think about the “ideal” length of life.

Those of us who are already 75 or older can enjoy the beauty of winter. And for the rest of you who have not yet reached winter, let me assure you that it will be here faster than you think.

Note: This blog posting – and more than 300 others – can also be found at http://theviewfromthisseat.blogspot.com