The book says higher intensity training can be dangerous but there is a lot of "press" lately on replacing "long, boring cardio" (30 min or more) with shorter duration (20 minutes) of interval cardio.So which should I do?
Leon, good evening I hope you are well and having a great night. With regard to your question, consider the following. While low intensity work will burn a higher percentage of calories from fat, higher intensity work will burn MORE overall calories. The goal is to create a caloric deficit of 3,500 calories below your weekly caloric intake to facilitate a 1 pound reduction in bodyfat per week.
Consider the following. If you walk at 3 MPH it will take you 20 minutes to complete a mile burning approximately 4 calories per minute or 80 overall calories (at an average weight of 150 lbs). At the same weight, if you trained at a higher intensity at 8 MPH you would complete the mile 7.5 minutes burning approximately 16 calories per minute or 120 calories.
During the same 20 minute period walking at 3 MPH where you would burn only 80 calories if you ran for 20 minutes at 8 MPH you would burn 320 calories during the same 20 minute period.
At the lower intensity (3 MPH) you would burn about 80% fat/20% carbohydrates in general or 64 calories from fat and 16 calories from carbohydrates at 3MPH for 20 minutes.
At the higher intensity (8 MPH) you would burn about 80% carbohydrates/20% fat in general or 256 calories from carbohydrates and 64 calories from fat.
As you can see you will burn an equal amount of calories from fat given the same 20 minute period.
We hope this helps. Take care and have a great night.
