Читать книгу HIIT Your Limit. High-Intensity Interval Training for Fat Loss, Cardio, and Full Body Health онлайн

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Students always ask me, what about the proteins? Don’t proteins provide a lot of energy for exercise? Actually, proteins are used only sparingly for fuel during exercise. Here’s why: the proteins you eat are digested and broken down into specific amino acids. Most of these amino acids are used to make new proteins, which build and repair muscles, tissues, skin, and bones; other amino acids help make hormones and messenger chemicals for the body. What amino acids don’t do, however, is power a workout.

The deep involvement of the body’s two energy systems, aerobic and anaerobic, is part of what makes HIIT workouts so unique. Let’s journey a little deeper into these systems.

The Aerobic Energy System: The Long-Term Energy Source

The aerobic energy system is the chief energy production system of the body, and the most efficient one. The term aerobic literally means “with oxygen.” As the name implies, this energy system cannot work unless there is sufficient oxygen available in the muscles during exercise. It takes about 5 minutes to fully turn on the pathways for the aerobic energy system to provide enough ATP for the workout. In other words, your aerobic system needs a brief start-up period before it provides enough ATP for your muscles to complete a sustained HIIT workout.