I have some advice for both of you: If yu can afford it, but a heart-rate monitor. I wear mine daily. Check your heart-rate at various times during your workout and check in with how you feel after those workouts. When I started training, I was really out of shape. 2 1/2 years ago I weighed 232 pounds and was almost no muscle. I had been pushing a pencil while sitting on my butt for the past 15 years.

I started by walking 1 mile each morning to lunch while LCing. My heart-rate while walking was around 110. I felt good during and after the walks so I gradually increased until I was walking faster and greater distances (up to 20 miles a day). Then I added treadmill climbs, then spinning classes, then step-aerobics, weightlifting, elliptical training and then century bike riding. I just finished doing a century ride today and yesterday. Part of the way through, however, my heart-rate during workouts started hitting the 155-165 area. I didn't feel as well after these workouts and in the week after. Through trial and error, I have come to discover that the best workouts I have are when I average 130-140 beats per minute. I finish these workouts feeling good and wanting to come back for more.

You can buy a watch-type heart-rate monitor with strap for about $60 at Target, or you can buy a strapless one (like mine) for about $120 at athetic or speciality stores.

It's true that the harder you work, the more calories you burn. But if the workout depletes your glycogen store, your glycogen window will open and you will feel like you hit the wall, and you will be very hungry for carbs. Many sport nutritionists incorrectly conclude that you have to eat more carbs when working out. I feel that if you listen to you body (and monitor your heart-rate), you can adjust your workout to an optimal fat-burning and truly enjoyable experience, without falling back on carbs to fuel it.

A great book on the subject was written by the worlds greatest LC endurance athelete: Stu Mittleman and his book: "Slow Burn".

J