Dr Mikes Blog

OK,  lets end the debate about target heart rate and fat burning.  The main difference between someone who is in shape and someone who is a couch potato, is not their muscles, it is the amount of red blood cells they have. Red blood cells fill with oxygen in the lungs everytime you breath and the heart pushes them through out your body to all of your cells.  Professional athletes will often cheat this system with a process called blood doping.  They will remove a liter of their blood one month before their big event. Their bodies replace the missing blood, and the night before the contest they add the other blood back in, giving them 6 liters instead of 5 liters of red blood cells.  Why would they do this?  Muscle cells burn sugar, fat and oxygen to make energy, this process is called aerobic metabolism. The more oxygen you can get to the muscles means more energy available for performance (strength and endurance).  We used to think that if we want to burn more fat, we should exercise at a level where this process is at a maximum of fat burning = ” target heart rate”  Makes sense right.  Well, when a person does cardio exercise at their target heart rate, and they stay in the “aerobic zone” for more than 20 minutes, they start burning extra fat, as well as sugar, and oxygen, but only while they are doing the exercise.  In a recent study on metabolism,  they took 100 obese people and had them ride the bicycle for 60 minutes a day, 6 times per week, at their target heart rate for a period of 6 months. The next 100 people rode the bikes for 30 minutes, 3 times per week, for 6 months, but they were instructed to ride at a steady pace for 3 minutes then sprint as fast as they could for 1 minute and then back down to a steady pace for 3 minutes again and repeat for 30 minutes (basically a hill program).  At the end of 6 months, the people who really worked out 75% less often, actually lost 9 times as much fat and weight as the other group.  How is this possible? let me explain.  I like to use the example of a sprinter, have you ever seen a fat one?  They only run 100 yards.  Yet they are lean, ripped, and muscular. why?  When you do an aerobic activity in the target heart rate zone you are only burning extra fat while you work out. The people who were doing the hill program were pushing their bodies into what is called “oxygen debt”. Where the muscles can no longer efficiently work aerobically(with oxygen) and are forced to work an-aerobically (without oxygen). When the muscles are working harder then the lungs and heart can keep up with, you reach oxygen debt, and the muscles are forced to burn sugar only to make energy. (an-aerobic metabolism). The problem… they can’t do this for very long and eventually you have to stop the exercises altogether.  But if you repeatedly do this type of exercise, you body responds by producing more and more red blood cells, so when you try and drive it again into oxygen debt it gets harder and harder.. the benefit is… with all of these extra red blood cells floating around in your blood, every time you breath normally, (15 times per minute), there is now a lot more oxygen in your body’ s blood and in your muscle cells and in turn you burn more calories during your normal daily activities and even more while you work out (= increased metabolism).  Give it a try you will be amazed at the results. (caution, when you increase your metabolism like this you tend to be extra hungry so watch the calories you eat)  If you would like more information check us out on the web

Dr Mike
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