I was wondering. I spin/indoor cycle as my main source of cardio exercise. I am starting to read conflicting data on which is better long steady paced rides (60 minutes) at 20+mph or short rides (20-30 minutes) at 30mph. My bike computer says I am going 30mph but I always think those things are off, so I always down play the data given, like the calories burned etc. Anyone have a preference, or who has tried both and found one works better than the other for fat loss?

Well, I am MUCH slower than you on the bike but I'll give my example anyway. What I do is something like two minutes at 10mph then 20 seconds as fast as I can go (yeah, I know that seems really slow to you but for me, its not). I do that for as long as I can handle it. I don't pay attention to the calories burned. I think you should do whatever works for you. If you prefer one over the other, do the one you prefer. If you have no preference, then mix it up. I guess it would also depend on what your goals are for the moment and where you are in reaching them. That is my slower-than-a-snail non professional opinon.

Scientists wanted to know if there was any difference between the effect of one long bout of aerobic exercise and three short bouts on perceived effort, calories burned and fat burned. They also wanted to test the ability of the exercise to help subjects metabolize a high-fat meal eaten 12 hours later. So they had male and female subjects perform either a 30-minute treadmill run at 80% of their max heart rate or three 10-minute bouts of running at the same intensity, separated by 20-minute rest periods. They discovered no difference between the total calories burned or the amount of fat burned, but the intermittent bouts felt much easier than the continuous run. What's more, they found that the short bouts significantly lowered the amount of fat that showed up in the subjects' blood after eating the high-fat meal. This means that short, multiple bouts of cardio may help you store less dietary fat and better protect you from cardiovascular disease.

CONTINUOUS CARDIO
Calories Burned 238
% Fat Burned 20%
Circulating Fat 325 g
Exertion 13

INTERMITTENT CARDIO
Calories Burned 236
% Fat Burned 27%
Circulating Fat 253 g
Exertion 11

Figure created using data from Altena et al, 2003.

Losing body fat is about losing calories.

So ( in theory at least ) if 60 minutes of cardio burns more calories than 20 - 30 minutes does, then over time ( and all other things being equal ) you'll shed more body fat over time by doing 60 minutes vs. 20 - 30 minutes.

ty for the reply but I meant two 30 minute workout in place a long 60 minute session, I realize now I didn't include that in my post.