Monday, March 10, 2008

Meet the MET's

No, I am not referring to the New York baseball team; but rather that obscure, "nobody knows what it means" display on most cardiovascular equipment. So, the questions to be asked is what is a MET and how can it help me. A MET or “metabolic equivalent” is a unit for measuring oxygen uptake. During exercise, as the intensity rises and the need for oxygen becomes apparent, the body needs to adjust and find a way to meet this demand, so an increased respiration rate occurs (heavy breathing). So, it can be said that the more challenging the exercise the greater the metabolic demand will be. MET's also have a direct relationship to caloric expenditure (energy output) and heart rate. As the breathing rate increases so does the demand for blood to the working muscles, so there is a linear increase in heart rate; along with the need for more energy (calories) since the body is working harder to sustain the current effort level. This information is nothing ground breaking or revolutionary since anyone could have guessed that jogging at 6 MPH would be more strenuous than walking at 3 MPH and therefore requires more oxygen, will impose a higher heart rate and use more energy. This is partly the reason why the MET display on most pieces of equipment is forgone in favor of more eye catching displays like Pace, Distance, or Calories; however, the MET display can be very valuable to the “intellectual” exerciser.

To demonstrate, I will use a tried and true fitness center stable, the treadmill. How many times have you read about the importance of gradually increasing the intensity in order to cause an overload, thus leading to improved fitness? In terms of using a treadmill that means increasing the speed, distance covered, elevation, or time on the machine. All of which are very productive ways to make the exercise more demanding. But what about the exerciser who can’t run as fast or as far as they used to, but still wants to utilize the treadmill to become more fit. What option do they have? Well if you can remember from previous posts on this blog spot, the most important factor in improving fitness is working hard and causing the body to elevate past its current capabilities, not necessarily increasing the workload. Running happens to be a very enjoyable activity for many people; however, it can also be very strenuous on the joints due to the pounding on the legs and lower back. The faster the pace the more stressful the activity becomes. This is where MET's come into play. For example, a person running at 6.1 MPH at 0 % grade (which is just under a 10 minute mile) uses approximately 10.34 MET's. If this pace was continued for 20 minutes they would complete just over 2 miles. Now let’s say the same person decided to run at 5 MPH but increased the elevation to 5 % (this is about a 12 minute mile), this would also approximate the MET's at 10.34. If this pace was continued for 20 minutes just over 1.5 miles would be completed.

So what’s the difference? In terms of energy expenditure, cardiac output, or respiration rate (which are the principle factors in improving cardiovascular fitness), not much. However, in the second example, by reducing the speed the individual would cover less distance, will reduce the pounding and compression of just under ½ mile; not to mention the torque on there hips and back from taking a longer more powerful stride. The end result is less wear and tear on the body. Now I am not saying to eliminate running or “faster runs” from you program, I still feel it is up to each individual to figure out what is best for them; but I also feel that it is very important to find ways to improve ones fitness without “stressing” the joints or connective tissue. So, how can MET's help you? Well they’re a tool and like all tools they have a function, if their function matches your needs than meet the MET and have a ball. - Douglas Scott