What's the difference?
I realize that there is a difference in heart rate for both, but what is better?
My target heart rate (being 22, 139 lbs, and for 20 minutes) is 158. If I choose random at level 2 on the elipitcal, my heart rate goes as high as 180. Is that bad? I realize the HR monitor might not be very accurate, but if it starts at 120-140, then obviously my HR is going up fairly high.

Also, is there a major difference between the stair climber, elipitcal, and bike? I get tired so quickly on the eliptical and stair climber, but feel like I could sit on the bike for an hour and not tire as quickly.

Is it better to stick at one level on the eliptical? Is it better to go to a higher level and only do it a short period of time? My biggest fear as I go through the weight loss is that I'll have to do more and more cardio to keep my weight down. I can't see myself on the eliptical for *gasp* an hour!

I always choose the fat burn option on the eliptical and the display always ends up telling me to slow down because my heart rate is above the level for fat burn but I keep going at the speed I'm comfortable at anyway! I alternate between the treadmill and the eliptical because it appears they burn more calories than the bike. I'm with you, I could do the bike for hours but I don't seem to get as good a work out.

I've been doing these machines for four months now and I'm up to an hour a day. I read somewhere (I can't remember where) that an hour a day is about all the cardio you should do. When I go hiking though, it ends up being around 2 hours. Now, that's a workout!

As you become more conditioned, your heart rate maximum increases- your heart and cv system can tolerate more intensity. If 120 bpm used to be your rate, then 170 will become your rate, for example. So yes, the more you do it, the more you have to do to keep up. You can increase the time (to no more than 60 minutes), or you can increase the intensity.

There are two types of cardio you can do- steady state or intensity intervals. Steady state means that you keep the speed/intensity at the same level for a time period. Intensity intervals means that you go all out for 30-60 seconds then take a minute or two to recover. Either way is good for weight loss and cardio vascular benefits. Mix it up.

You also don't have to stay on one machine for an hour. You can do 30 minutes on one and 30 minutes on another. As sunshine mentioned, hiking is also another good option. Although it may take 2-3 hours to complete a hike, it's not as though you maintain a high level for the full time. I wouldn't worry that an outdoors activity takes over 60 minutes. It's too enjoyable to cut out or cut down.

Hope this helps...

If the HR monitor is showing that you are STARTING at 120-140 BPM, you either need to see a doctor before continuing cardio or get a functioning heart rate monitor. Or maybe I'm misunderstanding what you wrote.

If you don't want to spend endless hours doing cardio, how about adding some strength training to your workouts? Muscle will help you burn more calories and you'll look a lot better once the fat is off, too

Mel