title: Effect of post-exercise caffeine and green coffee bean extract consumption on blood glucose and insulin concentrations.
abstract: OBJECTIVE
  The aim of this study was to investigate the effects of ingesting caffeine and green coffee bean extract on blood glucose and insulin concentrations during a post-exercise oral glucose tolerance test.
  
  
  METHODS
  Ten male cyclists (age: 26 ± 5 y; height: 179.9 ± 5.4 cm; weight: 77.6 ± 13.3 kg; body mass index: 24 ± 4.3 kg/m(2); VO2 peak: 55.9 ± 8.4 mL·kg·min(-1)) participated in this study. In a randomized order, each participant completed three 30-min bouts of cycling at 60% of peak power output. Immediately after exercise, each participant consumed 75 g of dextrose with either 5 mg/kg body weight of caffeine, 10 mg/kg of green coffee bean extract (5 mg/kg chlorogenic acid), or placebo. Venous blood samples were collected immediately before and after exercise during completion of the oral glucose tolerance test.
  
  
  RESULTS
  No significant time × treatment effects for blood glucose and insulin were found. Two-h glucose and insulin area under the curve values, respectively, for the caffeine (658 ± 74 mmol/L and 30,005 ± 13,304 pmol/L), green coffee bean extract (637 ± 100 mmol/L and 31,965 ± 23,586 pmol/L), and placebo (661 ± 77 mmol/L and 27,020 ± 12,339 pmol/L) trials were not significantly different (P > 0.05).
  
  
  CONCLUSIONS
  Caffeine and green coffee bean extract did not significantly alter postexercise blood glucose and insulin concentrations when compared with a placebo. More human research is needed to determine the impact of these combined nutritional treatments and exercise on changes in blood glucose and insulin.
authors.affiliation: Department of Health, Exercise, and Sports Sciences, University of New Mexico, Albuquerque, New Mexico. Electronic address: Jason.beam@sfcc.edu.
authors.forename: Jason R
authors.initials: JR
authors.lastname: Beam
authors.affiliation: Department of Health, Exercise, and Sports Sciences, University of New Mexico, Albuquerque, New Mexico.
authors.forename: Ann L
authors.initials: AL
authors.lastname: Gibson
authors.affiliation: Department of Exercise Science, School of Sport, Recreation and Exercise Sciences, Lindenwood University, St. Charles, MO.
authors.forename: Chad M
authors.initials: CM
authors.lastname: Kerksick
authors.affiliation: Department of Individual, Family, and Community Education, University of New Mexico, Albuquerque, New Mexico.
authors.forename: Carole A
authors.initials: CA
authors.lastname: Conn
authors.affiliation: Department of Health, Exercise, and Sports Sciences, University of New Mexico, Albuquerque, New Mexico.
authors.forename: Ailish C
authors.initials: AC
authors.lastname: White
authors.affiliation: Department of Health, Exercise, and Sports Sciences, University of New Mexico, Albuquerque, New Mexico.
authors.forename: Christine M
authors.initials: CM
authors.lastname: Mermier
mesh_terms: D000328:Adult; D001642:Bicycling; D001786:Blood Glucose / Q000378:metabolism*; D015992:Body Mass Index; D002110:Caffeine / Q000008:administration & dosage*; D002726:Chlorogenic Acid / Q000008:administration & dosage; D003069:Coffee / Q000737:chemistry*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D015444:Exercise; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood*; D008297:Male; D010936:Plant Extracts / Q000008:administration & dosage*; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D003069:Coffee; D007328:Insulin; D010936:Plant Extracts; D002726:Chlorogenic Acid; D002110:Caffeine
keywords: Carbohydrate; Chlorogenic acid; Cycling, glycogen; Insulin sensitivity index; Oral glucose tolerance test