Your Energy Systems Defined!

Do you know which energy system(s) you use when you exercise and how they contribute to reaching your fitness goals? Unless you are a trainer, you likely don’t know the answer to this question even though it is one of the most important factors in reaching your fitness goals.

Your body operates on three different energy systems: Phosphagen system, glycolysis, and the aerobic system, which are classified into two types of exercise: anaerobic and aerobic exercise.

Aerobic & Cardio Exercise.

The terms aerobic and cardio are often used interchangeably but should not be. Aerobic exercise relates to any exercise that utilizes major muscle groups continuously for 5 minutes or more. Cardiovascular exercise refers to any exercise that trains your cardiovascular system in an interval type manner.

Some examples of aerobic exercise are jogging, biking or paddling for more than 5 minutes in duration at a steady heart rate of around 65% of your maximal heart rate. This style of aerobic training focuses on improving your aerobic energy system through steady heart rate training.

Some examples of cardio types of exercise are high intensity intervals of sprints, calisthenic exercises or plyometrics that use an external weighted load of 0% to 25% of your body weight. Cardio type intervals can last a duration of 20 seconds to 2 minutes, at a variable heart rate that tops out at 90% to 95% of your maximal capacity, which improves both your aerobic and glycolysis energy systems.

Where does strength training fit in?

Anaerobic exercise is strength training at a load of 25% or more of your body weight for a duration of less than 20 seconds. Anaerobic set push your heart rate to 95%+ of maximal, which improves your phosphagen energy system and increases lean muscle mass. There is a lot of dispute, even in scientific articles, of where these lines should be drawn but you have to draw them at some point in order to create workouts that help you progress and actually get you to your goals.

Aerobic exercise involves activities like jogging, swimming, and biking whereas anaerobic exercise is a traditional strength workout with weighted squats, chest press, and curls. There are exercises that should be classified somewhere in between. Basketball, high intensity interval training, push ups, sprints and calisthenics are all types of exercise I refer to as cardio. They utilize both aerobic and anaerobic energy systems throughout the duration of the exercise.

For this reason I treat them as categorically different when I construct my workout plans. This is why we use aerobic, cardio, and anaerobic as three separate terms with three different meanings in our class descriptions and when we create custom exercise plans for our Personal Fit Plan clients.

Knowing the energy system or combination of systems that will best help you reach your fitness goals will get you there faster, healthier and with far less risk of injury and greater chance for success.