I'm 52 yr old and in some what a good shape, over weight about 100 pd with a pacemaker. I want to start running/joggin and  I have started walking and riding my bike to work about 4-5 miles 2 times a week. I walk 4-5 times a week 3 miles on my lunch hour and  I lift weights 2 times a week.  Now my knee is hurting and burning, I have ice it and cut back my bike riding to give it some rest for about a week.  Now my knee seem fine and to get back to work again, but I do not want to injury my knee again. I do not want to lose my groove that I have going on! 

Any advice on how to stay accident free while working out? Will it be okay for me to walk/jog (1min/walk1 min jog) and build my self up to a full jog of 3 miles with out damaging my knee? If and only if I hurt my knee, I want to stay movitated not to stop for time for my heatlh, I must lose this weight.  Thanks