Jean-Louis:


>>2. For a healthy young person: do not exercise intensely
>> more than two hours a day. That upper limit is of course
>> reduced for sick or older people.
>>
>>4. Do not practice only vigorous exercise, and do not
>> practice only gentle exercise (exceptions: elderly,
>> disabled, sick people, etc).


Hi J.L. I wouldn't assume too much about older people. I
recently read an article about a woman who took up weight
training at the age of 72 when she read that it would be
beneficial to her bones. Her trainer observed how determined
she was, always showing up in inclement weather, etc., and
encouraged her to get into body building competition. Now
79, she has won several championships and could as of the
writing do squats (don't know how many) with 100 lbs.
across her shoulders. Her skin looked very smooth (shaved
and oiled for competition, of course), a little wrinkly only
around the knees.
I kick myself for not saving the article. It was very inspiring
to yours truly, who tends to think of herself as over-the-hill at
44.

Cheers,
Martha