A question I commonly get asked is,”What burns more fat? If I do high intensity cardio or if I do low intensity cardio?” The answer of course is you want to do high intensity cardio! However, which burns more fat, well typically that is low intensity cardio; but here’s where it gets tricky.
The issue is that low intensity cardio stays in an aerobic state. If your body is in an aerobic state it’s main fuel source will usually be fat (your body has 3 main fuel sources; fat, protein and carbohydrates). Even though you may be burning say 50% fat during your aerobic cardiovascular work, it is 50% of a small total, typical hour of low intensity cardio may burn around 400 calories for the average person. So you burnt about 200 calories from fat. And if you really want to break that down, fat gives 9 calories/gram, which means you burnt of about 22 grams of fat. To put things in perspective one Big Mac is 550 calories and 29 grams of fat!!! (Information from Mcdonolds.com) WOW! So if you ate one of those your exercise session was pointless?? Not completely, you have to consider that after exercising your metabolism will stay at a heightened level for some time. In this case 1 hour of low intensity cardio you may see increased caloric burn for an additional 1-3 hours. Not to mention the many many other health benefits that comes along with any amount of exercise.
Now lets talk about high intensity cardiovascular exercise. In a typical hour the average person will burn between 800 and 1000 calories. That’s amazing! Now you can eat two Big Macs! Just kidding, I don’t recommend eating any unless your trying to have a heart attack; just watch the movie Super Size Me. So with high intensity cardio you are burning twice as many calories. Excellent, but, how many of those calories are from fat? A much lower percentage, this is because high intensity cardio is anaerobic, meaning your body is not getting enough oxygen and without oxygen your body cannot burn fat as a fuel source. Now of course you are getting some oxygen, but just not enough to meet your metabolic demands, therefore fat cannot be the primary fuel source. The primary fuel becomes carbohydrates, assuming your properly fed. So lets say your still burning 20-25% of your calories from fat. Well than your total caloric burn from fat during exercise is still about the same as when you did low intensity cardio, it’s just a smaller percentage. BUT HERE IS THE CLINCHER; after a high intensity exercise session your body will remain burning calories at an increased rate for up to 12 hours!!!! To further support high intensity cardio the percentage of calories from fat you will be burning for those next 12 hours after you are done and your heart rate slows down will go back to about 50-60% calories from fat.
To sum things up high intensity cardio will have much better longer lasting effects on the body and results will be seen much faster than in low intensity cardio. Another thing to think about, I usually only do 20-30 minutes of high intensity cardio, that’s plenty to see amazing results. You still get the increased metabolic rate after and if your working anaerobically during those 20-30 minutes, believe me it will be enough. Always remember to build yourself up to this, don’t go out tomorrow and try to do 15 sets of 100 meter sprints. Work at your level, always be sure to get your doctors approval (I recommend a chiropractor) to do high intensity exercise and work with a trainer to help you get started. Go kick some butt!!!
David Hopper
BTW, I am always open to questions; david@powerpunchgloves.com
