It's not just excercise, its doing the right cardio exercises. You need to get your heart rate in what health experts call your target heart rate, stay with me on this one. During your workout (whether it be running, treadmill, biking, whatever...), if you keep in the target heart rate, you will be doing wonders for your body. Here is how to find the THR-------
Take your age, Im 20 so Ill use that in the example.
Find maximum heart rate. 220-age(20)= 200
so my maximum heart rate is 200
Take your maximum heart rate, then you are going to multiply it by between 65%-85%
People who are in bad shape, multiply MHR by 65% up to 70%. Good shape, multiply it by 75-85%.
Im in good shape so i will multiply my MHR by 80%
200* .80 = 160
So during the workout if i keep my pulse to 160, then its all gonna be goooooood!