I'll be 56 the end of the month, about 20# overweight female. Last year I bought a new bike (Specialized Secteur Elite Comp) and averaging about 12 mph. I ride about 5-6 days a week. I guess I equate faster = fitter. Yes? No? Maybe? Is the best way to improve by riding more or incorporate some type of intervals? I work 4 - 10 hour days(my job involves standing 100%). My main goal for riding is fitness, weight loss, and maybe something like a 1/2 century/century. I joined a local bike club but all of their rides are over 15 mph. Any advice on training? How do you train? Thank you for any feedback