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.
McAnulty
Steven R
SR
Dept. of Health, Leisure, and Exercise Science, Appalachian State University, Boone, NC 28608, USA.
McAnulty
Lisa S
LS
Morrow
Jason D
JD
Nieman
David C
DC
Owens
John T
JT
Carper
Cristin M
CM
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