62-year-old geezer. Torn knee cartilage and surgery persuaded a
change from jogging to low impact ski machine.
Jogged 50 min. per day; 6-7 days per wk.; heart rate usually just
under target range.
Ski machine 35 min. per day; 6 days per wk.; heart rate within target
range even without using arm feature.
Ski machine has been much more cardio-intensive, with much huffing and
puffing. About half the time, I'm unable to complete the 35 min.
session in one fell swoop. I need to hop off the machine from 1 to as
many as 4 times to rest for a minute or so.
However, it has been necessary to cut back food intake fairly
significantly to maintain bodyweight with 6% fat. Apparently, the
more leisurely but longer jogging periods were less cardio-intensive
but burned more calories.
For whatever all that's worth.
Jack