Many factors can impact actual and perceived energy levels, including sleep quality and duration, body composition, mental and physical stress, nutrient/meal timing, and the levels of physical and mental activity. However, the heart of energy production in the body is the mitochondria.
Energy is neither created nor destroyed, but it can be transferred. In simple terms, the human body “transfers” energy from ingested food. While this process centers on making and breaking the “energy molecule” adenosine triphosphate (ATP) inside the mitochondria, the body undertakes this energy transfer in several ways depending on available nutrients and enzymes, oxygen status and duration and intensity of exercise.
Thus, nutritional approaches to energy management can be highly personalized for different levels of athletes and active consumers, and the different types of exercise or sporting activities they do. The emerging field of nutrigenomics offers the potential to further personalize energy-focused supplementation.
The tiny cellular energy powerhouse
Mitochondria are found inside the cytoplasm of most of the body’s eukaryotic cells—those that contain a nucleus and organelles. Some such cells have more mitochondria than others, depending on energy demands. For instance, the skeletal muscles have high energy requirements and contain more mitochondria than other body cells.1
The body’s energy process operates under two conditions determined by oxygen availability: aerobic or anaerobic. Short duration physical activity is fueled anaerobically. Longer exercise, when increased oxygen is available, is fueled aerobically.
The first 10 or so seconds of exercise is a low oxygen state, and relies on stored ATP and quickly restored ATP in the muscles. This is called the phosphagen system because stored phosphates can be used to quickly resynthesize ATP—after breaking a phosphate bond from ATP to release energy, the resulting adenosine diphosphate (ADP) needs to acquire a phosphate to become ATP again. This is where creatine shines. Phosphocreatine donates a phosphate to ADP for a quick conversion to ATP.
This is an excerpt from INSIDER's personalized energy and sports performance digital magazine. Download the full story and rest of the issue here.