The effects of obesity and exercise on the pharmacokinetics of caffeine in lean and obese volunteers

Abstract

The effects of obesity, exercise, and the interaction of obesity and exercise were examined in 6 caffeine naive, untrained, nonsmoking, college males (3 lean (LV), 3 obese (OV]. Each subject received caffeine (oral, 5.83 mg X kg-1 lean body weight) or placebo (50 mg citrate) prior to 3 h of seated rest and prior to 90 min of treadmill walking (40% of their maximal aerobic power) followed by 90 min of seated recovery. Serum samples were collected at various times and analyzed for caffeine by HPLC. Pharmacokinetic analysis indicated that at rest, OV had a significantly higher absorption rate constant (Ka 0.0757 vs. 0.0397 min-1), lower elimination rate constant (Ke 0.0027 vs. 0.0045 min-1), and longer serum half-life (t1/2 4.37 vs. 2.59 h) in comparison to LV. In exercise, as well as at rest LV and OV had a large difference in the volume of distribution (43.2 vs. 101.1) (rest, 54.1 vs. 103.1). Exercise consistently resulted in a decrease in the maximal serum concentration of caffeine and the area under the curve in OV while having no consistent effect on LV. The interactive effects of obesity and exercise could not be dissociated. However, these results demonstrate that both obesity and exercise have modified the pharmacokinetics of caffeine.

The effect of caffeine on energy balance

“…This demonstrates an impairment of the final degradetion of dimethylxanthines into monomethylxanthines, the end products of caffeine metabolism. These results agree with those in the study of Kamimori et al [52], which described a longer half-life and a slower elimination rate constant for caffeine in obese subjects.…”

“…The pharmacokinetics of caffeine is different in lean and obese subjects [7,[51][52][53]. It was found that caffeine amplifies fat oxidation better in lean vs. obese women [6,7].…”

“…Previous studies have found that the pharmacokinetics of caffeine is different between lean and obese subjects [7,[51][52][53]. For example, Kamimori et al [52] examined the effect of obesity on the pharmacokinetics of caffeine in six college males [three lean (LW) and three obese (OW)]. Each subject received either caffeine (oral, 5.83 mg/kg lean body mass) or a placebo (50 mg citrate) prior to 3 h of seated rest.…”

Effect of Caffeine on Fatigue During Submaximal Isometric Contractions at Different Knee Angles

“…Males were recruited, as the use of oral contraceptives can augment the half-life of caffeine [19], and throughout the luteal phase of the menstrual cycle caffeine clearance can be reduced [20]. Subjects were non-smokers, as nicotine can adjust the rate of caffeine degradation [21]. Subjects with a low caffeine intake were recruited as it was shown that chronic consumption can result in the up regulation of adenosine receptors and therefore reduce caffeine's acute effects [22].…”

Effect of Caffeine on Leg-Muscle Pain during Intense Cycling Exercise: Possible Role of Anxiety Sensitivity

“…Participants (N = 16) were nonsmoking college-age women of average body weight who reported low to moderate daily caffeine consumption (i.e., ≤200 mg/day) and no hypersensitivity to caffeine. Only nonsmokers of average body weight (i.e., BMI ≤25) were recruited to avoid the effects of cigarette smoking (Joeres et al, 1988) and obesity (Kamimori, Somani, Knowlton, & Perkins, 1987) on the rate of caffeine metabolism. Participants who reported low to moderate daily caffeine consumption were recruited to minimize tolerance of the effects of caffeine among habitual consumers of caffeine (Laska et al, 1984).…”