You need to keep your heart rate up for at least 30 min. 3-4 times a week, in the least, and best to do cardio 6 days. But don't forget how important strength training is. We have a tendency to think that we want to just lose weight by sweating.
When you do cardio first, your body uses sugars to give it energy (from your last meal), which is the reason why many women get light headed or even nauseous when doing cardio (esp. first thing in the mornings and without a good breakfast.) But when you do at least 30 -40 min. of strength training FIRST, your body will go straight to the fat to find its energy.
So do 5-8 min. of a warm up (like brisk walking on a track or treadmill, or eliptical, or bike), then 30-40 min. toning with light weights and routines, THEN 30-40 min. of cardio. :) With a good 1500-1800 calories a day and reg. exercise this way, you'll find losing weight to be fun and effective.
at 11:46 PM on Jun. 4, 2009