Influence of carbohydrate, intense exercise, and rest intervals on hormonal and oxidative changes.
This study compared effects of carbohydrate (CHO) and rest on oxidative stress during exercise. Cyclists (N = 12) completed 4 randomized trials at 64% Wattsmax under 2 conditions (continuous cycling for 2 h [C] and cycling with 3-min rest every 10 min for 2.6 h [R]). Subjects cycled under each condition while receiving 6% CHO and placebo (PLA). CHO and PLA were given preexercise (12 mL/kg) and during exercise (4 mL x kg(-1) x 15 min(-1)). Blood was collected preexercise, postexercise, and 1 h postexercise and assayed for F2-isoprostanes, hydroperoxides (LH), nitrite, antioxidant capacity, glucose, insulin, cortisol, and epinephrine. F2-isoprostanes and LH were lower in CHO. Glucose, cortisol, and epinephrine exhibited significant effects, with postexercise levels of glucose higher and cortisol and epinephrine lower in CHO during the R condition. This pattern was identical in the C condition (21). Oxidative stress during cycling was unaffected by use of short rest intervals but was diminished by CHO.
Dept. of Health, Leisure, and Exercise Science, Appalachian State University, Boone, NC 28608, USA.
Steven R
SR
McAnulty
Lisa S
LS
McAnulty
Jason D
JD
Morrow
David C
DC
Nieman
John T
JT
Owens
Cristin M
CM
Carper
D000328:Adult; D001642:Bicycling; D018592:Cross-Over Studies; D004040:Dietary Carbohydrates / Q000494:pharmacology*; D004837:Epinephrine / Q000097:blood; D028441:F2-Isoprostanes / Q000097:blood; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D006861:Hydrogen Peroxide / Q000097:blood; D007328:Insulin / Q000097:blood; D008297:Male; D009573:Nitrites / Q000097:blood; D018384:Oxidative Stress / Q000187:drug effects*; D010806:Physical Education and Training / Q000379:methods; D010807:Physical Endurance / Q000187:drug effects / Q000502:physiology*; D005082:Physical Exertion / Q000187:drug effects / Q000502:physiology
D004040:Dietary Carbohydrates; D028441:F2-Isoprostanes; D007328:Insulin; D009573:Nitrites; D006861:Hydrogen Peroxide; D006854:Hydrocortisone; D004837:Epinephrine