I am just starting out doing some riding for fitness and to lose weight. I was a recreational rider prior to this mostly riding MUP trailering my 2 boys behind. I upgraded from a Raleigh Venture Comfort bike to a Trek 7300 Hybrid. I have been out two times a day this week riding around my neighborhood and I can't seem to make it more than 15 minutes or so and not more than 3 miles at a time. When I was riding recreationally just last year, we were doing 11 miles at a time and that was pulling a 3 year old and a 1 year old in a Trek Trailer(heavy). I had no training prior to this and was only moderately more active. I have been around 260lbs for almost 10 years now, gaining and losing a few pounds here and there. Like I said, I was moderately more active in the past, but not by much.
I was originally worried about my back, but that feels great after I ride. My asthma is what has been getting me. I am very out of shape. I basically sat around the house this entire winter and played Daddy Daycare. I didn't think I was that out of shape in only 4 months, but little to no exercise and gaining a few pounds has really set me back quite a bit.
I am dieting, as I need to lose about 100lbs, but am I taking the wrong approach to biking? Should I start out walking first to build up some endurance before I ride? Should I go back to the paths I am used to? It is aggravating me and I feel like I am giving up after only 15 minutes of exercising, but I only stop when I physically cannot go any further.
Any recommendations or ideas would be greatly appreciated. I am not very good at this physical activity and exercise, but I have to do something or my days are numbered.