People tend to focus on the numbers too much ... 3.5 at 1 incline, a resistance of 15, whatever. But the fact is that those numbers are totally meaningless.
When I first started exercising, I could barely do 10 mins on the elliptical machine at 0 resistance. My heart pounded, I sweated, I was out of breath, and my legs were sore when I quit.
A month later I could go all day at that same setting, barely breathing hard.
What the settings are only have meaning in relation to HOW YOU FEEL.
The best indicator of how effective your
cardio is, is YOU. How do you feel? There is a rating called the perceived exertion scale - how much do YOU feel you're exerting yourself. Is your
heart rate up? Can you talk? Can you breathe? Are you going so hard you feel like you can't keep it up? Are you just strolling along?
You want to be putting out effort when you work out. You want your
heart rate to be elevated, you want to be pushing yourself. You don't have to run if you don't want to - you can increase exertion by raising the incline on the
treadmill or by moving to another piece of equipment and increasing the resistance.
But .. I'll add another piece of advice.
You shouldn't rely on
cardio for all of your exercise. If you really want to burn
fat and maintain muscle, and if you want to get that lean, toned look, you should lift
weights and do
body resistance
exercises. And I'm not talking "girly" lift a 5lb weight a zillion times type of weight lifting. I'm talking REAL weight lifting, using heavy
weights and compound
exercises. Things like squats, lunges, bench presses, dips, pushups, and so forth. Those things will give you a GREAT workout and help you get that lean look that people dream of when they're losing weight.