In reviewing for a fitness recertification, I came across some information that answered a question I am often asked, except I wasn't really sure it did answer the question.
Since then I have been trying to track down some of the many other things that I have read and now I feel like I squandered 30 minutes away when I just should have been blogging outright.
The questions I am often asked are what burns the most calories, when does fat get burned and what should one eat to fuel their workouts. A lot of that was addressed in the IFA training manual.
At the same time, our national physical activity guidelines tell us just to get moving, any amount, any activity, just move. And that is still true. However, there is a difference between training for optimal performance and fitness and being active to reduce your risk of chronic disease. The latter category will be the one that is addressed by 30 minutes of activity 5 days of week, in any block of time you can achieve. Ten minutes - three times a day, will work. And remember,sitting all day, regardless of your regular exercise routines, is NOT a good idea and could have adverse health outcomes.
Otherwise I will tell you this. Within the first 15 minutes of aerobic exercise (where the body uses oxygen to burn energy - running, walking, step, rowing, swimming, hiking, etc) the body is using the glycogen or carbohydrate stored in your muscles. After that sustained 15 minutes, the body will be look for fat to burn as energy. As a matter of fact, the fat is burned the most during that first hour and not much more so if you exercise longer.
Remember, we are seeking one or two things with this level of activity, to burn fat (calories) and to improve our cardio-respiratory fitness - the ability of our heart and lungs to use oxygen efficiently. So what should you fuel your body with if you are taking an aerobics class, going for a walk or run, or using the gym cardio equipment? Not sugar! And not sports drinks. If you have those things in your blood stream then insulin will be released. That is supposed to happen if you have eaten a simple carbohydrate, but insulin prevents the liver from metabolizing fat. A complex carbohydrate will do you more good. I always choose carbs and protein together for a sustained energy source, i.e. peanut butter on whole wheat bread, but NOT a whole sandwich, just a half or less. Another good choice is peanut butter and apple slices. The best thing to drink before, during and after your exercise is water.
If you are an extreme athlete or a long distance runner, football player, etc - you must realize, this message is not meant for you.
Lastly, for some people the main point is to burn calories. If that is your goal then just exercise and don't worry about all of these things. Track you calorie burn with the awesome resources available at the Stand Up and Eat site of the Cooper Institute. BTW, they have a great download section as well with handouts and such that can guide your progress.