How Hard Are You Working?

Your rate of perceived exertion corresponds directly to heart rate during exercise, so stick close to the expert-suggested levels of intensity to help you perform better and burn maximum calories.

"After you monitor RPE for a week, gauging it comes naturally no matter how or where you're exercising," said personal trainer Marco Reed, creator of Beyond Fit Boot Camp in Los Angeles.

Ask yourself several times per workout which number from one to 10 corresponds to how you're feeling:

1. Sit still, quiet reading
2. Light effort, strolling
3. Moderate walking, warm-up and cool-down levels
4. Moderate plus, like walking 4 mph on a flat track
5. Moderately intense, walking fast enough to almost jog 5 mph
6. Intense, hiking up a steep hill and feeling breathless
7. More intense, running about 7 mph or taking an indoor cycling class
8. Fast work, like running in deep sand or doing plyometric power jumps
9. Nearly too high, definitely uncomfortable and gasping for breath
10. Way too high, heart is thumping and muscles are on fire, you're panting; time to decrease intensity.

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