The Fat Burning Zone and YOU
Published: November 20, 2015
What does "working in the fat burning zone mean"? In particular, what does it mean for you and your physical activity or exercise plan? Do you have to be very fit to gain the benefits that working in your fat burning zone offer?
What are you burning when you're not burning fat as an energy source?
The term "working in the fat burning zone" has been applied to exercising aerobically within a particular heart rate range which is thought to optimally burn body fat as an energy source.
Your primary sources of energy are glucose and fats. Fatty acid oxidization is the process by which energy is released from the fat stored in your body.
Other compounds, such as pyruvate from glucose, are also oxidised to produce energy. The process of oxidation requires oxygen.
Aerobic (in the presence of oxygen) exercise or physical activities are performed so that the amount of oxygen you breath in is sufficient to meet the demands for energy of your working muscles.
To obtain health and/or physical fitness benefits from your aerobic exercise or physical activity you need to be moving your large muscles such that your heart rate increases above your resting heart rate. The average resting heart rate is about 70 beats per minute (BPM). To obtain health and physical fitness benefits from your aerobic activities you need to get your heart rate to between 50% and 85% of your maximum heart rate.
There are several methods to determine your maximum or maximal heart rate, but an easy way, but not the most accurate, is to deduct your age from 220 BPM. If you are 35 years of age the calculation will be: 220-35=185 BPM = your maximum heart rate (the highest heart rate a person can attain).
When the intensity of your exercise is low then more of your energy is provided by fatty acids and less by glucose. As the intensity of your exercise increases, identified by an increase in breathing and heart rate, less energy is provided by fat and more by glucose.
The fat burning zone is the heart rate range which identifies with the optimal amount of energy coming from fat. Your fat burning zone is usually set between 50-60% of your maximum heart rate.
Using the BPM of 185 the fat burning range will be 92.5 -111 BPM. Within this range you are potentially obtaining 50% of your energy calories from fat and 50% from...
Whitney, E. & Rady Rolfes, S. (2005). Understanding Nutrition. Belmont, CA: Thomson Wadsworth
CSEP (2003).The Canadian Physical Activity, Fitness & Appraisal. Health Canada
American Council on Exercise (1996). Personal Trainer Manual. San Diego, CA: American Council on Exercise
Centre for Health Promotion and Research (1995). Exercise, biochemistry and fat loss.