I noticed that having reached my seventies I also benefit from a little warmup before hitting the ride seriously. For example on my trainer I ride at an 84 cadence doing just over 14mph for ten minutes. After that I drop down to 78 and pop up the gear to get just over 15 mph. I suffer from exercise induced asthma and if I go out when it's a bit cool or I start off too hard my bronchial passage aches throughout my entire ride or even the rest of the day. Sucks, but the alternative is not riding.

Rich