I'm a long time lurker of this blog and forums, and just recently purchased the primal fitness book and am about half-way through. My problem is probably opposite of most as I'm not trying to lose weight or get in shape. I'm a male, 43 /5'9 with weight that is between 155/160 and still wear a 29-30 inch waist pants, the same as when I was 18. My build appears to be similiar to Marks. People think I'm 30 and are usually shocked to hear my age.
I've pretty much followed the same routine for 20 plus years since it works, but I'm burned out on it. I try to stay informed with health and fitness trends and found primal a couple of years ago.
While my routine is mostly based on conventional wisdom, all this primal/mark's daily apple information makes ALOT of sense to me, more than what I currently do. Just because I basically follow cw, Marks way sounds better to me and makes more sense so I don't want to seem like I'm promoting cw, I'm not. I just figure I have good genes.
My main fear is that by switching to primal I will lose what I have. I see other guys my age that have declined while, I have mainly at least stood still for the last 20 years. I know guys who have also hit the weights hard and probably roids, looked huge for a few years, tore something up and now cant' hardly walk and are now in bad shape.
Everytime I try sprinting and replace the jogging, I go back to my same old routine. I'll maybe sprint on Sat., take sunday off and just walk and by Monday, I'm back to my old routine.

I'd like to hear from others who were mostly in good shape from conventional wisdom, but switched to primal. I'd like to hear of what benefits and improvements were made. Just need a push to help me stick to it.

I'll list below my current routine if anyone is interested.
Thanks, in advance.

My routine is basically jogging 4 days a week for 30 minutes(Sat, Sun, and Tues., Wed.) Monday, Thurs. and Fri. are off days. MY jogging is mostly slow, but I do mix in intervals. I have certain points where when I get to them, I pick up the pace for so many yards to mostly a slow sprint. I do a set of 60 pushups on those days 3 times a day scattered out for a total of 180, or some days I will just do 1 all out set of pushups in 2 mins, usually totally around 120. And I usually do 3 sets of 20 chin ups. I also wear a pedometer and try to get 15,000 steps a day.
I really don't have to watch what I eat.(my wife hates me) For breakfast I eat 4 chocolate chip cookies. If I want slim up a little in the summer, I'll just cut down to 3 or 2 cookis. 3 cups of coffee, creamer only no sugar. Lunch is a handful of peanuts and an apple and a banna.......everyday. Supper is just whatever, nothing specific and sometimes its eating out. Not usually anything really healthy.
Maybe a beer once a month.
Great blood pressure, no health problems, never been on medication no need for viagra.