Any exercise is better than no exercise when it comes to weight loss and overall health. However, there is a difference in the amount of fat burned based on the level of intensity involved. Understanding the difference between percentage of fat and volume of fat is crucial to maximizing burning fat calories. Most treadmills offer the technology to assist you in maintaining a pace within your fat-burning zone.
Percentage vs. Volume
When the body is at rest, it is primarily using fat as its predominant fuel source. Carbohydrates and even, to a small degree, proteins are also being used, but at a smaller percentage. As activity levels increase, so too does the percentage of carb utilization. Even though the body burns primarily fat at rest and low intensities, the amount or volume is low. Low activity does not require a lot of energy to sustain it.
As intensity increases, more energy is needed. So, even though the percentage of fat as a fuel source balances out with carbs, more fat is used to meet the energy demand. The volume of fat used increases as the percentage of fat decreases, to a certain point.
Lactate Threshold
At approximately 65 percent of maximum energy output, the percentage of fat-to-carb usage is virtually even. Intensities that exceed this level rely exclusively on carbs as oxygen availability begins to decrease, and fat needs oxygen present to be oxidized, or broken down. The lactate threshold, also referred to as the anaerobic threshold, is the point where fat as an energy source can no longer meet the demand of the intensity. Carbs can be oxidized without the presence of oxygen.
Therefore, it is at this point of the lactate threshold where oxygen availability is reduced due to the elevated intensity level, that carbs are broken down to produce adenosine triphosphate, or ATP, the body's primary source of energy. Knowing approximately at which point you reach your lactate threshold is central to fat-burning and subsequent weight-loss efforts.
Fat-burning Zone
Most modern treadmills have colorful illustrations on their display units that indicate specific zones based on your current heart rate. These zones are generically based upon information you input into the treadmill before beginning your exercise, such as age and weight. What is not taken into consideration is your current fitness level. Nevertheless, maintaining levels in the areas on the display described as "weight loss" or "fat-burning" zones will ensure that you are more than likely burning a higher volume of fat during your workout.
Recommendation
Walking slowly on a treadmill does burn primarily fat for energy. Unfortunately, it is a relatively small amount of fat. More calories from fat will be burned at submaximal intensities. Make an effort to achieve an intensity at or just below the lactate threshold level to maximize fatty oxidation, or breakdown.
Considerations
Interval training is a viable option to maximize fat-burning. Interval training is a hybrid concept that incorporates training techniques of both high and low intensity exercise routines. Basically, you execute high-intensity intervals followed by lower-intensity intervals or recovery periods. Maximum calorie burning is achieved at or near maximum effort. Intervals allow you to reach these levels without reaching complete fatigue.
Work-to-rest ratios should be between 1:1 to 1:3. In a 1:1 ratio, recovery period will last the exact same time as the high intensity interval. In a 1:2 ratio, the rest or recovery time is double that of the higher level. An example of the 1:3 ratio would be to perform a two minute high intense interval followed by a six minute low intensity period.
References
- "Sports and Fitness Nutrition"; Robert Wildman and Barry Miller; 2004
- "NSCA's Essentials of Personal Training"; National Strength and Conditioning Association; 2004
Member Comments