Rushall notes, 1990.

Caffeine. Some research suggests that a caffeine dosage of 5 mg/kg/BW usually causes free fatty acid level to peak after about 60 min and remain elevated for about 3 hours at about three to four times that of normal levels. This effect is delayed by almost two hours if sugar is taken concurrently.

Heparin is a drug with similar properties. Research is not conclusive on this effect, that is, replications of this effect are not always obtained.

High carbohydrate meals. A high CHO meal causes blood insulin to rise and stay elevated for 60-90 minutes. Insulin works against performance because it slows fatty acid mobilization from fat cells and slows the breakdown of glycogen in the liver. This suggests that after a meal or a sweet drink, the only energy sources that are readily available are muscle glycogen and a small amount of glucose in the blood. These sources are used rapidly and could result in hypoglycemia, which would reduce endurance capacity.

Carbohydrate ingestion during exercise. CHO ingestion during exercise does not reduce muscle glycogen use but it could spare the use of liver glycogen if taken early enough. It may prolong exercise marginally if sufficient time is made available for it to enter the blood stream, that is, if it empties from the stomach. That is a difficult task but in low level efforts, or intermittent effort sports, it is possible to gain such a benefit.

Glycogen use and heat. The rate of muscle glycogen use appears to be increased in elevated environmental temperatures (heat).

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