Exercise?

I don't think I'm getting enough exercise! I don't mean stuff like walking- I do plenty of that. Not long ago I walked the Woodville rail & tunnel track. A once a year thing run by the Woodville Lions as a fundraiser , walks through 3 tunnels and 8km long. Not steep, of course, because trains don't like steep, but still it was no problem. I went with eldest son Stephen in case I needed a 'carry' but no problem. No, what I mean is anaerobic activity. Stuff that makes me puff, so I jumped on Jill's exercycle which has an onboard computer that tells you how far you've gone, what your heart rate is , what speed you're going and how many calories you have consumed . I thought I'd concentrate on distance! Only one kilometer but I started of on 2min 45 secs. Next day was 2min 34secs and today 1min 54sec. I don't think that is a world record but it's a start- and it did make me puff!