Metabolic characteristics of keto-adapted ultra-endurance runners

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• 作者：Jeff S. Volek^a ; ^b ; ^{volek.1@osu.edu" class="auth_mail" title="E-mail the corresponding author} ; Daniel J. Freidenreich^a ; ^b ; Catherine Saenz^a ; ^b ; Laura J. Kunces^a ; Brent C. Creighton^a ; Jenna M. Bartley^a ; Patrick M. Davitt^a ; Colleen X. Munoz^a ; Jeffrey M. Anderson^a ; Carl M. Maresh^a ; ^b ; Elaine C. Lee^a ; Mark D. Schuenke^c ; Giselle Aerni^a ; William J. Kraemer^a ; ^b ; Stephen D. Phinney^d
• 关键词：VO2max ; maximal oxygen consumption ; HC ; high-carbohydrate ; LC ; low-carbohydrate ; FASTER ; Fat Adapted Substrate use in Trained Elite Runners ; RPE ; ratings of perceived exertion ; DXA ; dual-energy X-ray absorptiometry ; RER ; respiratory exchange ratio ; USG ; urine specific gravity ; ELISA ; enzyme-linked immunosorbent assay ; NEFA ; non-esterified fatty acid ; HOMA ; homeostatic model assessment of insulin resistance ; IP ; immediately post-exercise ; PE-120 ; 120  ; min post-exercise
• 刊名：Metabolism
• 出版年：2016
• 出版时间：March 2016
• 年：2016
• 卷：65
• 期：3
• 页码：100-110
• 全文大小：746 K

文摘

Many successful ultra-endurance athletes have switched from a high-carbohydrate to a low-carbohydrate diet, but they have not previously been studied to determine the extent of metabolic adaptations.

Methods

Twenty elite ultra-marathoners and ironman distance triathletes performed a maximal graded exercise test and a 180 min submaximal run at 64% VO₂max on a treadmill to determine metabolic responses. One group habitually consumed a traditional high-carbohydrate (HC: n = 10, %carbohydrate:protein:fat = 59:14:25) diet, and the other a low-carbohydrate (LC; n = 10, 10:19:70) diet for an average of 20 months (range 9 to 36 months).

Results

Peak fat oxidation was 2.3-fold higher in the LC group (1.54 ± 0.18 vs 0.67 ± 0.14 g/min; P = 0.000) and it occurred at a higher percentage of VO₂max (70.3 ± 6.3 vs 54.9 ± 7.8%; P = 0.000). Mean fat oxidation during submaximal exercise was 59% higher in the LC group (1.21 ± 0.02 vs 0.76 ± 0.11 g/min; P = 0.000) corresponding to a greater relative contribution of fat (88 ± 2 vs 56 ± 8%; P = 0.000). Despite these marked differences in fuel use between LC and HC athletes, there were no significant differences in resting muscle glycogen and the level of depletion after 180 min of running (− 64% from pre-exercise) and 120 min of recovery (− 36% from pre-exercise).

Conclusion

Compared to highly trained ultra-endurance athletes consuming an HC diet, long-term keto-adaptation results in extraordinarily high rates of fat oxidation, whereas muscle glycogen utilization and repletion patterns during and after a 3 hour run are similar.