A Response to Petrie's Note on Statistical Analysis of Attitude Scale Scores

Abstract

On four separate occasions resting, fasted adults ingested 10 oz of a cola-flavored soft drink containing either 0, 22.5, 35, or 150 mg caffeine. Heart rate, blood pressure, and plasma free fatty acid (FFA) and glucose values were obtained before and at 15, 30, 60, 90, 120, 180 and 360 min after the feeding. All urine was collected during the 6 hr following ingestion and was later assayed for total catecholamine (CA) content. Urine volume and total CA excretion increased as the amount of caffeine ingested increased. Only the 150 mg solution resulted in significant increases (over control) in 6 hr CA output, or FFA concentration and mean arterial pressure early after the feeding. The 150 mg drink also maintained blood glucose at pre–ingestion levels for the entire course of the experiment. The moderate increase in circulating FFA following ingestion of a commercially available cola (22 to 35 mg caffeine/bottle) is similar to the change seen in resting, nonfed subjects. These data suggest that ingestion of caffeine in an amount typically found in a single bottle of cola drink does not increase factors associated with coronary risk, nor will it have a positive influence on parameters associated with enhanced athletic performance, should those same changes occur during exercise.