I bought a MTB two years ago (a Scott Aspect 30) but quickly found that I was so far out of shape that trail riding wasn't my thing at that stage in the game. Ultimately, what I really wanted to do with a bike was to just get out there and enjoy cycling like I did as a teen (gosh those days are so long gone!) and eventually for commuting. I sold the Scott and a few weeks ago, picked up a BMC Alpenchallenge AC01 Hybrid (which I also love). However, my conditioning is still far from ideal.
A little more background: I'm 48 years old, weigh 84kg down from a high of 97kg, a Type 2 diabetic and had a very minor heart attack 3 years ago. I was a smoker at the time, very sedentary and ate very poorly. The day of my heart attack, I vowed to change my life and quit smoking then and there. I also slowly began walking... starting with less than 1km walks to today where I walk between 7-30km daily. But walking is very time consuming and I feel I'm at the point where I don't benefit from it anymore. Biking would hopefully bring me to the next level. At this stage of biking though, I still tire easily (mostly because I have this insatiable need to bike fast all the time) but I know my condition will improve as I get out there more often. I still have a belly and need to lose approximately another 20kg.