title: The effect of ad libitum ingestion of a caffeinated carbohydrate-electrolyte solution on urinary caffeine concentration after 4 hours of endurance exercise.
abstract: The purpose of the present study was to examine the effect of ad libitum ingestion of a carbohydrate-electrolyte solution (CES) with 150 mg x L (-1) caffeine (CAF) on urinary CAF concentration after 4 h of endurance exercise. Fifty-eight healthy and well-trained male subjects ingested ad libitum a 7 % CES with 150 mg x L (-1) CAF during 4 h cycling at 50 % of maximal work capacity. Total fluid consumption (mean +/- SE) was 2799 +/- 72 mL and CAF intake was 420 +/- 11 mg (5.7 +/- 0.2 mg x kg (-1) body weight). The post-exercise urinary CAF concentration (4.53 +/- 0.25 microg x mL (-1)) was below the doping level of the International Olympic Committee (12 microg x mL (-1)) in all subjects (range 1.20 - 10.84 microg x mL (-1)). A highly positive correlation was observed between CAF intake and post-exercise urinary CAF concentration (r = 0.68, p < 0.001). It is concluded that ad libitum ingestion of a CES with 150 mg x L (-1) CAF during 4 h cycling resulted in post-exercise urinary concentration below the doping level in all subjects.
authors.affiliation: Department of Human Biology, Maastricht University, The Netherlands. E.Kovacs@HB.UNIMAAS.NL
authors.forename: E M R
authors.initials: EM
authors.lastname: Kovacs
authors.forename: A M
authors.initials: AM
authors.lastname: Martin
authors.forename: F
authors.initials: F
authors.lastname: Brouns
mesh_terms: D000328:Adult; D001628:Beverages / Q000009:adverse effects; D002110:Caffeine / Q000008:administration & dosage* / Q000009:adverse effects / Q000652:urine*; D002241:Carbohydrates / Q000008:administration & dosage*; D004244:Dizziness / Q000209:etiology; D004300:Doping in Sports; D004326:Drinking / Q000502:physiology; D004573:Electrolytes / Q000008:administration & dosage*; D004884:Eructation / Q000209:etiology; D015444:Exercise / Q000502:physiology*; D005414:Flatulence / Q000209:etiology; D006261:Headache / Q000209:etiology; D006801:Humans; D008297:Male; D010807:Physical Endurance / Q000187:drug effects*; D011595:Psychomotor Agitation / Q000209:etiology; D013223:Statistics as Topic; D013995:Time
chemical_list: D002241:Carbohydrates; D004573:Electrolytes; D002110:Caffeine