The Efficacy of Carbohydrate Supplementation and Chronic High-Carbohydrate Diets for Improving Endurance Performance

1999 ◽  
Vol 9 (1) ◽  
pp. 92-115 ◽  
Author(s):  
Kevin Allen Jacobs ◽  
W. Michael Sherman
Keyword(s):  
Body Weight ◽  
Endurance Performance ◽  
Endurance Athletes ◽  
Moderate Intensity ◽  
Review Of The Literature ◽  
Moderate Intensity Exercise ◽  
Carbohydrate Supplementation ◽  
Dietary Recommendation ◽  
High Carbohydrate ◽  
And Performance

Carbohydrate (CHO) is the body's most limited fuel and the most heavily metabolized during moderate-intensity exercise. For this reason it is recommended that endurance athletes consume a high-CHO diet (8-10 g CHO ⋅ kg body weight−1 ⋅ day−1) to enhance training and performance. A review of the literature supports the benefits of CHO supplementation on endurance performance. The benefits of chronic high-CHO diets on endurance performance are not as clear. Recent evidence suggests that a high-CHO diet may be necessary for optimal adaptations to training. However, the paucity of data in this area precludes any concrete conclusions. The practicality of high-CHO diets is not well understood. The available evidence would indicate that a high-CHO diet is the best dietary recommendation for endurance athletes.

scholarly journals Is Hemoglobin Mass at Age 16 a Predictor for National Team Membership at Age 25 in Cross-Country Skiers and Triathletes?

2021 ◽  
Vol 3 ◽  
Author(s):  
Jon Peter Wehrlin ◽  
Thomas Steiner
Keyword(s):  
Carbon Monoxide ◽  
Body Weight ◽  
Endurance Performance ◽  
Important Predictor ◽  
Endurance Athletes ◽  
Young Athletes ◽  
High Performing ◽  
National Team ◽  
Cross Country ◽  
Hemoglobin Mass

We recently measured the development of hemoglobin mass (Hbmass) in 10 Swiss national team endurance athletes between ages 16–19. Level of Hbmass at age 16 was an important predictor for Hbmass and endurance performance at age 19. The aim was to determine how many of these young athletes were still members of Swiss national teams (NT) at age 25, how many already terminated their career (TC), and whether Hbmass at ages 16 and 19 was different between the NT and TC group. We measured Hbmass using the optimized carbon monoxide re-breathing technique in 10 high-performing endurance athletes every 0.5 years beginning at age 16 and ending at age 19. At age 25, two athletes were in the NT group and eight athletes in the TC group. Mean absolute, body weight-, and lean body mass (LBM) related Hbmass at age 16 was 833 ± 61 g, 13.7 ± 0.2 g/kg and 14.2 ± 0.2 g/kg LBM in the NT group and 742 ± 83 g, 12.2 ± 0.7 g/kg and 12.8 ± 0.8 g/kg LBM in the TC group. At age 19, Hbmass was 1,042 ± 89 g, 14.6 ± 0.2 g/kg and 15.4 ± 0.2 g/kg LBM in the NT group and 863 ± 109 g, 12.7 ± 1.1 g/kg and 13.5 ± 1.1 g/kg LBM in the TC group. Body weight- and LBM related Hbmass were higher in the NT group than in the TC group at ages 16 and 19 (p < 0.05). These results indicate, that Hbmass at ages 16 and 19 possibly could be an important predictor for later national team membership in endurance disciplines.

scholarly journals Effect of high-fat and high-carbohydrate diets on pulmonary O2 uptake kinetics during the transition to moderate-intensity exercise

2014 ◽  
Vol 117 (11) ◽  
pp. 1371-1379 ◽  
Author(s):  
J. A. Raper ◽  
L. K. Love ◽  
D. H. Paterson ◽  
S. J. Peters ◽  
G. J. F. Heigenhauser ◽  
...  
Keyword(s):  
Blood Flow ◽  
Time Constant ◽  
Phase Ii ◽  
Tricarboxylic Acid Cycle ◽  
Microvascular Blood Flow ◽  
Moderate Intensity ◽  
High Fat ◽  
Moderate Intensity Exercise ◽  
Oxidation Rates ◽  
High Carbohydrate

Mitochondrial pyruvate dehydrogenase (PDH) regulates the delivery of carbohydrate-derived substrate to the mitochondrial tricarboxylic acid cycle and electron transport chain. PDH activity at rest and its activation during exercise is attenuated following high-fat (HFAT) compared with high-carbohydrate (HCHO) diets. Given the reliance on carbohydrate-derived substrate early in transitions to exercise, this study examined the effects of HFAT and HCHO on phase II pulmonary O2 uptake (V̇o2p) kinetics during transitions into the moderate-intensity (MOD) exercise domain. Eight active adult men underwent dietary manipulations consisting of 6 days of HFAT (73% fat, 22% protein, 5% carbohydrate) followed immediately by 6 days of HCHO (10% fat, 10% protein, 80% carbohydrate); each dietary phase was preceded by a glycogen depletion protocol. Participants performed three MOD transitions from a 20 W cycling baseline to work rate equivalent to 80% of estimated lactate threshold on days 5 and 6 of each diet. Steady-state V̇o2p was greater ( P < 0.05), and respiratory exchange ratio and carbohydrate oxidation rates were lower ( P < 0.05) during HFAT. The phase II V̇o2p time constant (τV̇o2p) [HFAT 40 ± 16, HCHO 32 ± 19 s (mean ± SD)] and V̇o2p gain (HFAT 10.3 ± 0.8, HCHO 9.4 ± 0.7 ml·min−1·W−1) were greater ( P < 0.05) in HFAT. The overall adjustment (effective time constant) of muscle deoxygenation (Δ[HHb]) was not different between diets (HFAT 24 ± 4 s, HCHO 23 ± 4 s), which coupled with a slower τV̇o2p, indicates a slowed microvascular blood flow response. These results suggest that the slower V̇o2p kinetics associated with HFAT are consistent with inhibition and slower activation of PDH, a lower rate of pyruvate production, and/or attenuated microvascular blood flow and O2 delivery.

Failure of Low Dose Carbohydrate Feeding to Attenuate Glucoregulatory Hormone Responses and Improve Endurance Performance

1991 ◽  
Vol 1 (4) ◽  
pp. 338-352 ◽  
Author(s):  
William A. Burgess ◽  
J. Mark Davis ◽  
William P. Bartoli ◽  
Jeffrey A. Woods
Keyword(s):  
Plasma Glucose ◽  
Perceived Exertion ◽  
Low Dose ◽  
Endurance Performance ◽  
Moderate Intensity ◽  
Carbohydrate Feeding ◽  
Glucoregulatory Hormones ◽  
Flavored Water ◽  
Hormone Responses ◽  
And Performance

The effects of ingesting a low dose of CHO on plasma glucose, glucoregulatory hormone responses, and performance during prolonged cycling were investigated. Nine male subjects cycled for 165 min at ≈67% peakfollowed by a two-stage performance ride to exhaustion on two occasions in the laboratory. Every 20 min during exercise, subjects consumed either a flavored water placebo (P) or a dilute carbohydrate beverage (C). Blood samples were collected immediately before, every 20 min throughout, and immediately after exercise. Plasma was analyzed for glucose, lactate, free fatty acids (FFA), and various glucoregulatory hormones., RER, heart rate, perceived exertion, and exercise performance were also measured. Lactate, FFA, epinephrine, norepinephrine, ACTH, cortisol, and glucagon increased with exercise whereas glucose and insulin decreased (p≤05). Except for a small difference in glucose at 158 min of exercise and at exhaustion, no significant differences were found between drinks for any of the variabfes studied (p≥ 05). Ingestion of 13 g carbohydrate per hour is not sufficient to maintain plasma glucose, attenuate the glucoregulatory hormone response, and improve performance during prolonged moderate intensity cycling.

Dietary Carbohydrate as an Ergogenic Aid for Prolonged and Brief Competitions in Sport

1995 ◽  
Vol 5 (s1) ◽  
pp. S13-S28 ◽  
Author(s):  
Janet Walberg-Rankin
Keyword(s):  
Body Weight ◽  
Blood Glucose ◽  
Weight Control ◽  
Moderate Intensity ◽  
Dietary Carbohydrate ◽  
High Quality ◽  
Quality Performance ◽  
High Carbohydrate ◽  
Carbohydrate Depletion ◽  
Body Weight Control

Reduction of body stores of carbohydrate and blood glucose is related to the perception of fatigue and the inability to maintain high-quality performance. This has been clearly shown with aerobic, endurance events of moderate intensity of over 90 min duration. Carbohydrate intake may also have relevance for athletes involved in short, high-intensity events, especially if body weight control is an issue. Prevention of carbohydrate depletion begins with a high-carbohydrate training diet of about 60-70% carbohydrate. If possible, carbohydrate beverages should be consumed during the event at the rate of 30-70 g/hr to reduce the chance of body carbohydrate depletion. Finally, replacement of body carbohydrate stores can be achieved most rapidly if 40-60 g of carbohydrate is consumed as soon as possible after the exercise and at repeating 1-hr intervals for at least 5 hr after the event.

Effects of diet on muscle triglyceride and endurance performance

1997 ◽  
Vol 82 (4) ◽  
pp. 1185-1189 ◽  
Author(s):  
Raymond D. Starling ◽  
Todd A. Trappe ◽  
Allen C. Parcell ◽  
Chad G. Kerr ◽  
William J. Fink ◽  
...  
Keyword(s):  
Endurance Performance ◽  
Cycling Performance ◽  
Moderate Intensity ◽  
High Fat ◽  
Fasting Period ◽  
High Carbohydrate ◽  
Triglyceride Concentration ◽  
Significant Difference ◽  
Before And After ◽  
Muscle Triglyceride

Starling, Raymond D., Todd A. Trappe, Allen C. Parcell, Chad G. Kerr, William J. Fink, and David L. Costill. Effects of diet on muscle triglyceride and endurance performance. J. Appl. Physiol. 82(4): 1185–1189, 1997.—The purpose of this investigation was to examine the effects of diet on muscle triglyceride and endurance performance. Seven endurance-trained men completed a 120-min cycling bout at 65% of maximal oxygen uptake. Each subject then ingested an isocaloric high-carbohydrate (Hi-CHO; 83% of energy) or a high-fat (Hi-Fat; 68% of energy) diet for the ensuing 12 h. After a 12-h overnight fast, a 1,600-kJ self-paced cycling bout was completed. Muscle triglyceride measured before (33.0 ± 2.3 vs. 37.0 ± 2.1 mmol/kg dry wt) and after (30.9 ± 2.4 vs. 32.8 ± 1.6 mmol/kg dry wt) the 120-min cycling bout was not different between the Hi-CHO and Hi-Fat trials, respectively. After the 24-h dietary-fasting period, muscle triglyceride was significantly higher for the Hi-Fat (44.7 ± 2.4 mmol/kg dry wt) vs. the Hi-CHO (27.5 ± 2.1 mmol/kg dry wt) trial. Furthermore, self-paced cycling time was significantly greater for the Hi-Fat (139.3 ± 7.1 min) compared with the Hi-CHO (117.1 ± 3.2 min) trial. These data demonstrate that there was not a significant difference in muscle triglyceride concentration before and after a prolonged moderate-intensity cycling bout. Nevertheless, a high-fat diet increased muscle triglyceride concentration and reduced self-paced cycling performance 24 h after the exercise compared with a high-carbohydrate diet.

Relationships Between Pacing Parameters and Performance of Elite Male 1500-m Swimmers

2016 ◽  
Vol 11 (2) ◽  
pp. 159-163 ◽  
Author(s):  
Patrycja Lipinska ◽  
Sian V. Allen ◽  
Will G. Hopkins
Keyword(s):  
Web Sites ◽  
Endurance Performance ◽  
Substantial Effect ◽  
Mean Value ◽  
Endurance Athletes ◽  
Time Variability ◽  
Performance Time ◽  
Scatter Plots ◽  
And Performance ◽  
Large Improvement

Purpose:Pacing has a substantial effect on endurance performance. The authors characterize pacing and identify its parameters for optimal performance in 1500-m freestyle swimming.Methods:Web sites provided 50-m lap and 1500-m race times for 330 swims of 24 elite male swimmers. Pacing for each swim was characterized with 7 parameters derived from a general linear model: linear and quadratic coefficients for the effect of lap number; reductions from predicted time for first, second, penultimate, and last laps; and lap-time variability. Scatter plots of race time vs each parameter for each swimmer were used to identify optimum values of parameters.Results:Most scatterplots showed only weak relationships between the parameter and performance, but one-third to one-half of swimmers had an optimum value of the parameter that was substantially different from their mean value. A large improvement in performance time (1.4% ± 0.9%, mean ± SD) could be achieved generally by reversing the sign of the linear parameter to make the slowest lap occur earlier in the race. Small to moderate improvements might also accrue by changing the quadratic parameter, by making the first and second laps slower and the penultimate and last laps faster, and reducing lap-time variability.Conclusions:This approach to analysis of pacing may help improve performance in swimmers and other endurance athletes in sports with multiple laps, but data from many competitions are required.

Well-Trained Endurance Athletes’ Knowledge, Insight, and Experience of Caffeine Use

2007 ◽  
Vol 17 (4) ◽  
pp. 328-339 ◽  
Author(s):  
Ben Desbrow ◽  
Michael Leveritt
Keyword(s):  
Body Weight ◽  
Standard Deviation ◽  
Side Effects ◽  
Endurance Performance ◽  
Cross Sectional Study ◽  
Endurance Athletes ◽  
Sectional Study ◽  
Journal Articles ◽  
Cross Sectional ◽  
Food Items

This descriptive cross-sectional study assessed the perceptions, knowledge, and experiences of caffeine use by athletes competing at the 2005 Ironman Triathlon World Championships. Questionnaires were distributed to 140 athletes (105 men and 35 women, 40.3 ± 10.7 y old) representing 16 countries during prerace registration. A large proportion (73%) of these endurance athletes believe that caffeine is ergogenic to their endurance performance, and 84% believe it improves their concentration. The most commonly reported positive caffeine experiences related to in-competition use of cola drinks (65%) and caffeinated gels (24%). The athletes’ ability to accurately quantify the caffeine content of common food items was limited. The most popular sources of caffeine information were self-experimentation (16%), fellow athletes (15%), magazines (13%), and journal articles (12%). Over half the athletes (53%) could not identify an amount of caffeine required to improve their triathlon performance. Mean (± standard deviation) suggested doses were 3.8 (± 3) mg/kg body weight. Few side effects associated with taking caffeine during exercise were reported.

Warm-Up Strategy and High-Intensity Endurance Performance in Trained Cyclists

2015 ◽  
Vol 10 (3) ◽  
pp. 353-360 ◽  
Author(s):  
Peter M. Christensen ◽  
Jens Bangsbo
Keyword(s):  
Exercise Intensity ◽  
High Intensity ◽  
Performance Test ◽  
Recovery Period ◽  
Endurance Performance ◽  
Moderate Intensity ◽  
Peak Power Output ◽  
Moderate Intensity Exercise ◽  
Warm Up ◽  
Subsequent Performance

Purpose:To evaluate the influence of warm-up exercise intensity and subsequent recovery on intense endurance performance, selected blood variables, and the oxygen-uptake (VO2) response.Methods:Twelve highly trained male cyclists (VO2max 72.4 ± 8.0 mL · min−1 · kg−1, incremental-test peak power output (iPPO) 432 ± 31 W; mean ± SD) performed 3 warm-up strategies lasting 20 min before a 4-min maximal-performance test (PT). Strategies consisted of moderate-intensity exercise (50%iPPO) followed by 6 min of recovery (MOD6) or progressive high-intensity exercise (10–100%iPPO and 2 × 20-s sprints) followed by recovery for 6 min (HI6) or 20 min (HI20).Results:Before PT venous pH was lower (P < .001) in HI6 (7.27 ± 0.05) than in HI20 (7.34 ± 0.04) and MOD6 (7.35 ± 0.03). At the same time, differences (P < .001) existed for venous lactate in HI6 (8.2 ± 2.0 mmol/L), HI20 (5.1 ± 1.7 mmol/L), and MOD6 (1.4 ± 0.4 mmol/L), as well as for venous bicarbonate in HI6 (19.3 ± 2.6 mmol/L), HI20 (22.6 ± 2.3 mmol/L), and MOD6 (26.0 ± 1.4 mmol/L). Mean power in PT in HI6 (402 ± 38 W) tended to be lower (P = .11) than in HI20 (409 ± 34 W) and was lower (P = .007) than in MOD6 (416 ± 32 W). Total VO2 (15–120 s in PT) was higher in HI6 (8.18 ± 0.86 L) than in HI20 (7.85 ± 0.82 L, P = .008) and MOD6 (7.90 ± 0.74 L, P = .012).Conclusions:Warm-up exercise including race-pace and sprint intervals combined with short recovery can reduce subsequent performance in a 4-min maximal test in highly trained cyclists. Thus, a reduced time at high exercise intensity, a reduced intensity in the warm-up, or an extension of the recovery period after an intense warm-up is advocated.

scholarly journals Effect of Moderate-Intensity Exercise on Plasma C-Reactive Protein and Aortic Endothelial Function in Type 2 Diabetic Mice

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Nada Sallam ◽  
Majid Khazaei ◽  
Ismail Laher
Keyword(s):  
Body Weight ◽  
Endothelial Function ◽  
Moderate Intensity ◽  
Low Grade ◽  
C Reactive Protein ◽  
Moderate Intensity Exercise ◽  
Necrosis Factor Alpha ◽  
Reactive Protein ◽  
Low Grade Inflammation ◽  
Aortic Endothelial

The aim of this study was to evaluate the effects of moderate-intensity exercise on plasma levels of C-reactive protein (CRP) and tumor necrosis factor-alpha (TNF-α) as markers of low-grade inflammation and endothelial function in diabetic (db/db) mice. Control and db/db mice were divided into sedentary and exercised groups. Aortic endothelial function was evaluated after two- and six-week exercises using a wire myograph. Plasma CRP levels were measured at baseline, and after two and six weeks of exercise. Baseline plasma CRP levels were significantly higher in db/db mice compared to control (P<.05). After two weeks of exercise, aortic endothelial function was significantly improved without affecting body weight or plasma CRP levels. Six weeks of exercise not only improved endothelial function, but also significantly reduced body weight and plasma CRP levels in db/db mice. Thus short-term exercise has beneficial effect on endothelial function without reducing low-grade inflammation while more prolonged exercise periods are required to reduce inflammatory markers.

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