Tontoy
Like Tara mentioned, there's a cardboard sliding rule for activity. But until you pick it up, the old way still works - 20 min per earned activity point.
With the new activity card, depending on the level of exercise intensity and weight -- it seems you can earn even 2-3 points per 20 min based on the level of effort.
BUT --- keep in mind if you have a body that's used to a high level of intensity... it may not feel like high level to you. You need to be realistic. I've found that even if the card indicated I have "earned" 7 points for an hour of high intensity workout... if I constantly used up all these points I'd gain weight, not lose it.
If I work out for an hour high level, I count it for no more than 5 ponts. With this compromise, I find I can lose weight while using the extra points.
hope this helps
Patch