I've been convinced for a long time that riding the bike on a regular basis does contribute to muscle tone and a fitter feeling. All that hanging on against the wind etc is only done by muscle power. I read somewhere years ago that biking used twice as many calories as doing the same distance in a car (probably down to shivering)

When it comes to keeping fit in other ways motivation is the big problem. I'm sure that you have to have a reason to undertake a long term fitness regime or that you have to have others motivating you. Doing it yourself for no particular reason other than "I'm a slob, I've got to do something" is doomed to failure.

My wife and I run and we motivate each other but the only way we can manage more intensive training is to set a goal and work towards it. (Our current one is a half marathon next Easter). We have a local cycle track as part of our various circuits and have seen so many (usually middle aged (like ourselves)) solo men and women beginners do a couple of weeks and give up. Running to a level intense enough to alter your body is hard and you don't lose much weight from it unless you alter your diet at the same time.

Recently the whole thing has backfired on me. I was running 25 - 30 miles a week + a gym / yoga session with an ex olympic athlete preparing for overlanding to Mali /B.F. and went down with 2 stress fractures in my left foot, one after the other. That not only cancelled the trip but has kept me off the bike most of the year. Keeping things in proportion might be the lesson to be learnt.