Sports Nutrition: Fueling Physical Activity

Flashcards covering the mechanisms of ATP production, the timeline of energy system activation during exercise, and the physiological causes of fatigue based on sports nutrition principles.

Anaerobic Metabolism

The creation of ATP without oxygen present, occurring in the cytosol of cells, using only glucose to produce short-term ATP and generating lactic acid.

Aerobic Metabolism

The creation of ATP in the presence of oxygen, occurring in the mitochondria, using glucose, fatty acids, and amino acids to produce sustained ATP in high amounts.

Lactic Acid

A byproduct generated during anaerobic metabolism when glucose is used to create ATP without oxygen.

Cytosol

The location within cells where anaerobic metabolism occurs.

Mitochondria

The cellular organelle where aerobic metabolism takes place.

Creatine phosphate

A compound stored in muscles that is broken down to form ATP for about $10 ext{ seconds}$ after the first few seconds of exercise.

Instant energy

Energy sourced from stored ATP during the first few seconds of exercise, followed by the breakdown of creatine phosphate stored in the muscles.

Short-term energy

ATP produced primarily through the anaerobic metabolism of glucose from the blood or muscle glycogen, which operates at full capacity about $30 ext{ seconds}$ into activity.

Long-term energy

ATP produced after about $2 ext{ to }3 ext{ minutes}$ of exercise via aerobic metabolism using fatty acids and glucose as oxygen delivery increases.

Oxygen lag

The initial period during intense exercise where oxygen delivery and utilization by muscles are limited, causing muscles to rely on anaerobic metabolism.

Fatigue

The inability to continue activity at an optimal level, typically caused by low ATP generation due to fuel shortage or the accumulation of metabolic waste.

Glycogen depletion

The exhaustion of glucose stores in the liver and muscles, which is expedited by high-intensity exercise and leads to fatigue.