Interaction of training and diet on metabolism and endurance during exercise in man
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Interaction of training and diet on metabolism and endurance during exercise in man. / Helge, Jørn Wulff; Richter, Erik; Kiens, Bente.
I: Journal of Physiology, Bind 492, Nr. 1, 01.04.1996, s. 293-306.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › fagfællebedømt
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TY - JOUR
T1 - Interaction of training and diet on metabolism and endurance during exercise in man
AU - Helge, Jørn Wulff
AU - Richter, Erik
AU - Kiens, Bente
PY - 1996/4/1
Y1 - 1996/4/1
N2 - 1. Ten untrained young men ingested a carbohydrate-rich diet (65 energy percent (E%) carbohydrate, T-CHO) and ten similar subjects a fat-rich diet (62 E% fat, T-FAT) while endurance training was performed 3-4 times a week for 7 weeks. For another 8th week of training both groups ingested the carbohydrate-rich diet (T-CHO and T-FAT/CHO). 2. Maximal oxygen uptake increased by 11% (P <0.05) in both groups after 7 and 8 weeks. Time to exhaustion at 81% of pre-training maximal oxygen uptake increased significantly from a mean (+/- S.E.M.) of 35 +/- 4 min to 102 +/- 5 and 65 +/- 7 min in T-CHO and T-FAT, respectively, after 7 weeks (P <0.05, T-CHO vs. T-FAT). After 8 weeks, endurance remained unchanged in T-CHO but increased (P <0.05) to 77 +/- 9 min in T-FAT/CHO which, however, was still less (P <0.05) than in T-CHO. 3. Muscle glycogen breakdown rate during exercise was halved by endurance training equally in both T-CHO and T-FAT after 7 and 8 weeks, and muscle glycogen stores at exhaustion were not depleted in any group. 4. During exercise after 7 weeks, the respiratory exchange ratio (RER) was unchanged in T-CHO (0.88 +/- 0.01) compared with pre-training but decreased (P <0.05) to 0.82 +/- 0.02 in T-FAT. After 8 weeks, RER in both T-CHO and T-FAT/CHO was approximately 0.87. 5. During exercise, plasma noradrenaline concentration and heart rate were higher in T-FAT than in T-CHO both at 7 and at 8 weeks. 6. It is concluded that ingesting a fat-rich diet during an endurance training programme is detrimental to improvement in endurance. This is not due to a simple lack of carbohydrate fuel, but rather to suboptimal adaptations that are not remedied by short-term increased carbohydrate availability. Furthermore, the study suggests that the decrease in RER usually seen after training when exercising at the same absolute intensity as before training can be prevented by a carbohydrate-rich diet.
AB - 1. Ten untrained young men ingested a carbohydrate-rich diet (65 energy percent (E%) carbohydrate, T-CHO) and ten similar subjects a fat-rich diet (62 E% fat, T-FAT) while endurance training was performed 3-4 times a week for 7 weeks. For another 8th week of training both groups ingested the carbohydrate-rich diet (T-CHO and T-FAT/CHO). 2. Maximal oxygen uptake increased by 11% (P <0.05) in both groups after 7 and 8 weeks. Time to exhaustion at 81% of pre-training maximal oxygen uptake increased significantly from a mean (+/- S.E.M.) of 35 +/- 4 min to 102 +/- 5 and 65 +/- 7 min in T-CHO and T-FAT, respectively, after 7 weeks (P <0.05, T-CHO vs. T-FAT). After 8 weeks, endurance remained unchanged in T-CHO but increased (P <0.05) to 77 +/- 9 min in T-FAT/CHO which, however, was still less (P <0.05) than in T-CHO. 3. Muscle glycogen breakdown rate during exercise was halved by endurance training equally in both T-CHO and T-FAT after 7 and 8 weeks, and muscle glycogen stores at exhaustion were not depleted in any group. 4. During exercise after 7 weeks, the respiratory exchange ratio (RER) was unchanged in T-CHO (0.88 +/- 0.01) compared with pre-training but decreased (P <0.05) to 0.82 +/- 0.02 in T-FAT. After 8 weeks, RER in both T-CHO and T-FAT/CHO was approximately 0.87. 5. During exercise, plasma noradrenaline concentration and heart rate were higher in T-FAT than in T-CHO both at 7 and at 8 weeks. 6. It is concluded that ingesting a fat-rich diet during an endurance training programme is detrimental to improvement in endurance. This is not due to a simple lack of carbohydrate fuel, but rather to suboptimal adaptations that are not remedied by short-term increased carbohydrate availability. Furthermore, the study suggests that the decrease in RER usually seen after training when exercising at the same absolute intensity as before training can be prevented by a carbohydrate-rich diet.
KW - Adult
KW - Biopsy
KW - Blood Proteins
KW - Diet
KW - Dietary Carbohydrates
KW - Dietary Fats
KW - Energy Metabolism
KW - Exercise
KW - Fatty Acids
KW - Glycogen
KW - Heart Rate
KW - Humans
KW - Male
KW - Muscle, Skeletal
KW - Oxygen Consumption
KW - Physical Endurance
KW - Time Factors
U2 - 10.1113/jphysiol.1996.sp021309
DO - 10.1113/jphysiol.1996.sp021309
M3 - Journal article
C2 - 8730603
VL - 492
SP - 293
EP - 306
JO - The Journal of Physiology
JF - The Journal of Physiology
SN - 0022-3751
IS - 1
ER -
ID: 33862117