Hi, i'm new to this forum and would like to have an opinion:
I really like cycling, but I'm not like a racer or pro biker or anything. I live close to a bike path and have been going out everyday for anywhere between 12k-40k. I push it in some places and have found the biking is doing good stuff for my body, but I'm really into it more as a stress reliever. I feel a tiny bit of soreness in the evening, but it is gone by morning. Am I overdoing the biking? I'm sure that I am getting some cardio benefits, but like I said I'm not going all out for the whole ride. Since I am spending a lot of time biking, I'm not doing any other cardio because it's too nice outside to be inside on an ellpitical or something. Is there anything I can do to make this into more of an efficient workout?
Thanks for any advice.

Without knowing your speed or how long it takes you to go those 12 - 40k, it is hard to say what you are doing. I would recommend wearing a heart monitor - you can wear a wrist monitor with the chest strap or get a very cool computer that picks up the signal. Then, do a search on here for recommended heart rates for cardio. The formula (220-age) x .7 or .8 is a good starting point for most people and is what I use per my cardiologist's advice. BTW, make sure you are healthy enough for this.

Then, after monitoring your heart rate on your rides, you can increase or decrease the distance or speed to get a good cardio workout.

Cycling is by far my favorite cardio exercise.

Thanks for the reply.
I have an HR monitor, but I haven't used it much, it has a chest strap and it's itchy.
I've been trying to pay close attention to my percieved exertion, but sometimes the view gets in the way. 12k takes about half an hour, beyond that loop I'm not sure. I did 40k last Sat. in 2 and a half hours, but I stopped for lunch and to play on the monkey bars.
I'll pay closer attention to what my heart and lungs are telling me, and to make this daily excursion more about exercise than just spacing out.
BTW, you can do 7 pull ups unassisted? I feel good now, I can do 3, (but I'm not pulling up over 200 lbs like you are). Also the third one is not too good and it hurts.

I struggle on numbers 6 and 7...

You are pretty much flying with that cycling speed, what kind of bike do you have?
I bought a little thingie to measure speed/distance/time etc. and I am averaging about 21 KPH/18K/38 mins. I have a mountain bike (but no mountain, bumpy sidewalks in spots though) and I'm staying in 14 of 21 gears. I think I could go faster in a lower gear, but this one offers me good resistance on the legs.
Anyways, I'll try again for a better speed/time tomorrow.

With a mountain bike (mtb) on the road, I could probably do no better than about 16 mph (26kph I think) (although I don't have a computer on the mtb, so that is a wild-@ssed guess). A mtb is heavier, but more importantly you sit more upright, have wider tires (2+ inches vs. the 23mm tires on my roadie) and less pressure (60 psi on the mtb vs. 120 psi on the roadie).

I ride about 100 miles per week, usually 20miles on 2 or 3 weeknights and a 52mile ride each Saturday. Generally, I hammer as hard as I can for as long as I can. Here is my main road bike, a 19lb. Klein Quantum with a Campy Chorus groupo

Definetly flying on that bike.
Are you in the city? I've got a nice mix of park/bike path but after a certain point it's crumbling infrastrure! Since the parks follow the river I could ride to the end of the island, but that's way too far and potentially life threatening. Since I hate backtracking, I always seem to add km by trying to find a new way home.
My bike is heavy and is not high end enough to have a great suspension but I've acquired a tough butt

I have a computer on mine, and my average speed, oddly enough is 16mph. (My routine bike path has some downhills where I hit 28-30mph though) The reason I chose a mtn bike, is because I do enjoy the occasional trail, but the bike is heavier, and the knobby tires slow you down big time. This kind of resistance makes it a lot more of a workout for me. I've ridden a couple light road bikes, and they seem a lot easier to propel, so for the time being I'd like more workout for the time alotted.

(Not to mention I'm almost 300lbs, not sure I'm not really light enough for a road bike yet)

I'm exactly like you db67, I like to bike it for stress relief. I put down about 10 miles a day, usually in around an hour. If I have nothing better going on, I'll do 20. The benefits are paying off looks wise, but the way I feel is the real goal, better than ever!