Just finished a VO2 max/metabolic efficiency test with a great local runner here at our peak Performance Lab, Evans, GA. It’s a test that provides you with some invaluable, unique “data” that can really help fine tune your training. As mentioned in a previous post, building your “aerobic base” is critical early in the season. During the test, I like to take the runner or cyclist through various low intensity speeds or wattages to see how their metabolic system handles the changes in intensity. Specifically, how does your body fuel those intensities?
When you are exercising, your body is using chiefly either carbs or fats to breakdown and use for energy. When the exercise intensity is lower your body is more apt to use your stored fat for durations > 20 minutes of exercise. When the exercise intensity is higher, your body needs a quicker energy source and pulls carbs from muscle and liver stores to fuel the exercise; this however, is a limited energy source.
When you have a large aerobic base your body handles low to moderate intensity running/cycling with primarily fat utilization for energy. If your aerobic base is smaller you make a switch, called “the crossover point” where you burn carbs sooner in your exercise period…this can lead to early fatigue.
Your body has relatively massive amounts of fat storage (some of us more than others, author included) and minimal carb storage. For longer duration aerobic events (10k +) you need your body to be able to run/cycle for a long time before “switching” to carb utilization. The key is the aerobic base and your “base training”. With dedication to building your aerobic base in lower intensity, longer duration training early in the season you will also improve your “metabolic efficiency”, that is your ability to hold off the carb usage until later in your event….go longer, go faster, no bonking. During a metabolic VO2 test you will learn what heart rate ranges, what speeds or power outputs offer the best efficiency for training. So yes you need a metabolic exercise/VO2 max/metabolic efficiency test!
Train Smarter. Luke