Metabolic Efficiency Testing

Metabolic Efficiency (ME) is an exercise science/performance concept that is based on the body’s ability to use fat or carbohydrate as a fuel source during exercise. The basis of ME deals with the production of carbon dioxide (CO2) and oxygen consumption (O2) as carbohydrates and fats are oxidized (broken down) during exercise. When the body breaks down carbohydrates and fat for fuel differing amounts of O2 are need and different amounts of CO2 are produced. The concept of ME provides a framework for placing the body at the right intensity of exercise to utilize fat as the primary source of calorie burn during long duration endurance exercise bouts

The body (typically) has a large supply of fat stores and in the weight loss population our target of ME testing is finding the best intensity for exercise where storage fat is the primary fuel for exercise. In our endurance athlete performance population (runners, tri-athletes) the goal of ME testing is to find that speed, heart rate, or rating of intensity where fat-usage for fuel allows the “engine” to run for a longer time without fatigue. If the intensity of exercise is too high, the body switches to carbohydrate utilization primarily and fatigue is now “on the clock”. What this means for the endurance athlete is that you have a limited carbohydrate storage capability and once this is exhausted fatigue/exhaustion soon follows….and you will stop running or biking. If you can tap your fat storage (a much large energy pool) you can exercise/compete longer while preserving your carbohydrate stores.

How the test is performed:

  • 1. The client wears a Polar heart rate monitor (chest strap) for HR
  • 2. The client will then be fitted with a mask that covers the nose and mouth; to that mask a tube is connected that further connects to the metabolic cart. This apparatus collects all breaths during the exercise test.
  • 3. The client will walk, jog, or bike at varied speeds (lower intensity speeds) in 5 minute intervals on a treadmill or cycle trainer (Computrainer Lab). Typically 30-60 minutes of walking/jogging/biking is needed.

Helpful Testing Tips

  • 1. Bring your Ipod or music listening device to have while you run/bike.
  • 2. Familiarize yourself with running on a treadmill (if running test).

To schedule any testing at the PPL please contact Dr. Luke Heusel, PT,OCS @ 706-823-3807 or email: