GLOSSARY

Exercise Fatigue describes a reduced ability to sustain the required exercise task, with several interacting causes. It is not a specific diagnosis of glycogen depletion or one nutrient deficiency.

Fatigue is a reduced ability or willingness to sustain the required task and has interacting central and peripheral contributors. Low carbohydrate availability can matter, but heat, hydration, pacing, sleep, muscle damage and illness can also contribute. A late-race slowdown does not prove that all glycogen is exhausted or that blood glucose is low. Persistent or unusual symptoms require appropriate assessment. A useful fueling review investigates plausible causes instead of assigning every performance decline to one missing nutrient.

Glycogen use depends on exercise intensity, duration, recruited muscles, training status and starting availability. A decline in one sampled muscle or fiber population should not be assumed to represent all stores throughout the body. Carbohydrate feeding can support blood glucose and performance during suitable exercise, but it does not guarantee uniform sparing of muscle glycogen. Depletion is a change in a finite pool, whereas depletion rate specifies the speed over an observation interval.

Carbohydrate requirements vary with the intensity, duration and importance of the work. Daily intake relative to body mass describes a different quantity from an intake rate during exercise, which is commonly expressed per hour. A larger daily target does not mean the same amount should be consumed in every session. Match supply to the schedule, starting stores and practical tolerance, and distinguish grams eaten from grams absorbed or oxidized when discussing a fueling plan.