Metabolic and performance responses during endurance exercise after high-fat and high-carbohydrate meals

1998 ◽  
Vol 85 (2) ◽  
pp. 418-424 ◽  
Author(s):  
Helena A. Whitley ◽  
S. M. Humphreys ◽  
I. T. Campbell ◽  
M. A. Keegan ◽  
T. D. Jayanetti ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Oxygen Uptake ◽  
Endurance Exercise ◽  
Maximal Oxygen Uptake ◽  
Time Trial ◽  
Substrate Oxidation ◽  
High Fat ◽  
High Carbohydrate ◽  
And Performance ◽  
Fat Meal

We studied the effects of preexercise meal composition on metabolic and performance-related variables during endurance exercise. Eight well-trained cyclists (maximal oxygen uptake 65.0 to 83.5 ml ⋅ kg−1 ⋅ min−1) were studied on three occasions after an overnight fast. They were given isoenergetic meals containing carbohydrate (CHO), protein (P), and fat (F) in the following amounts (g/70 kg body wt): high-carbohydrate meal, 215 CHO, 26 P, 3 F; high-fat meal, 50 CHO, 14 P, 80 F. On the third occasion subjects were studied after an overnight fast. Four hours after consumption of the meal, subjects started exercise for 90 min at 70% of their maximal oxygen uptake, followed by a 10-km time trial. The high-carbohydrate meal compared with the high-fat meal resulted in significant decreases ( P < 0.05) in blood glucose, plasma nonesterified fatty acids, plasma glycerol, plasma chylomicron-triacylglycerol, and plasma 3-hydroxybutyrate concentrations during exercise. This was accompanied by an increase in plasma insulin ( P < 0.01 vs. no meal), plasma epinephrine, and plasma growth hormone concentrations (each P < 0.05 vs. either of the other conditions) during exercise. Despite these large differences in substrate and hormone concentrations in plasma, substrate oxidation during the 90-min exercise period was similar in the three trials, and there were no differences in performance on the time trial. These results suggest that, although the availability of fatty acids and other substrates in plasma can be markedly altered by dietary means, the pattern of substrate oxidation during endurance exercise is remarkably resistant to alteration.

scholarly journals Effects of fat adaptation and carbohydrate restoration on prolonged endurance exercise

2001 ◽  
Vol 91 (1) ◽  
pp. 115-122 ◽  
Author(s):  
Andrew L. Carey ◽  
Heidi M. Staudacher ◽  
Nicola K. Cummings ◽  
Nigel K. Stepto ◽  
Vasilis Nikolopoulos ◽  
...  
Keyword(s):  
Endurance Exercise ◽  
Power Output ◽  
High Fat Diet ◽  
Respiratory Exchange Ratio ◽  
Time Trial ◽  
Fat Oxidation ◽  
Significant Benefit ◽  
High Fat ◽  
Competitive Athletes ◽  
And Performance

We determined the effect of fat adaptation on metabolism and performance during 5 h of cycling in seven competitive athletes who consumed a standard carbohydrate (CHO) diet for 1 day and then either a high-CHO diet (11 g · kg−1 · day−1 CHO, 1 g · kg−1 · day−1 fat; HCHO) or an isoenergetic high-fat diet (2.6 g · kg−1 · day−1 CHO, 4.6 g · kg−1 · day−1 fat; fat-adapt) for 6 days. On day 8, subjects consumed a high-CHO diet and rested. On day 9, subjects consumed a preexercise meal and then cycled for 4 h at 65% peak O2 uptake, followed by a 1-h time trial (TT). Compared with baseline, 6 days of fat-adapt reduced respiratory exchange ratio (RER) with cycling at 65% peak O2 uptake [0.78 ± 0.01 (SE) vs. 0.85 ± 0.02; P < 0.05]. However, RER was restored by 1 day of high-CHO diet, preexercise meal, and CHO ingestion (0.88 ± 0.01; P < 0.05). RER was higher after HCHO than fat-adapt (0.85 ± 0.01, 0.89 ± 0.01, and 0.93 ± 0.01 for days 2, 8, and 9, respectively; P < 0.05). Fat oxidation during the 4-h ride was greater (171 ± 32 vs. 119 ± 38 g; P < 0.05) and CHO oxidation lower (597 ± 41 vs. 719 ± 46 g; P < 0.05) after fat-adapt. Power output was 11% higher during the TT after fat-adapt than after HCHO (312 ± 15 vs. 279 ± 20 W; P = 0.11). In conclusion, compared with a high-CHO diet, fat oxidation during exercise increased after fat-adapt and remained elevated above baseline even after 1 day of a high-CHO diet and increased CHO availability. However, this study failed to detect a significant benefit of fat adaptation to performance of a 1-h TT undertaken after 4 h of cycling.

Effect of High-Fat, High-Carbohydrate, and High-Protein Meals on Metabolism and Performance during Endurance Cycling

2002 ◽  
Vol 12 (3) ◽  
pp. 318-335 ◽  
Author(s):  
David S. Rowlands ◽  
Will G. Hopkins
Keyword(s):  
Oxidation Rate ◽  
Peak Power ◽  
Time Trial ◽  
Fat Oxidation ◽  
High Protein ◽  
High Fat ◽  
High Carbohydrate ◽  
Competitive Cyclists ◽  
And Performance ◽  
Meal Composition

The effect of pre-exercise meal composition on metabolism and performance in cycling were investigated in a crossover study. Twelve competitive cyclists ingested high-fat, high-carbohydrate, or high-protein meals 90 min before a weekly exercise test. The test consisted of a 1-hour pre-load at 55% peak power, five 10-min incremental loads from 55 to 82% peak power (to measure the peak fat-oxidation rate), and a 50-km time trial that included three 1-km and 4-km sprints. A carbohydrate supplement was ingested throughout the exercise. Relative to the high-protein and high-fat meals, the high-carbohydrate meal halved the peak fat-oxidation rate and reduced the fat oxidation across all workloads by a factor of 0.20 to 0.58 (p = .002–.0001). Reduced fat availability may have accounted for this reduction, as indicated by lower plasma fatty acid, lower glycerol, and higher pre-exercise insulin concentrations relative to the other meals (p = .04–.0001). In contrast, fat oxidation following the high-protein meal was similar to that following the high-fat meal. This similarity was linked to evidence suggesting greater lipolysis and plasma fat availability following high-protein relative to high-carbohydrate meals. Despite these substantial effects on metabolism, meal composition had no clear effect on sprint or 50-km performance.

A scientific nutrition strategy improves time trial performance by ≈6% when compared with a self-chosen nutrition strategy in trained cyclists: a randomized cross-over study

2012 ◽  
Vol 37 (4) ◽  
pp. 637-645 ◽  
Author(s):  
Kuno Hottenrott ◽  
Erik Hass ◽  
Manon Kraus ◽  
Georg Neumann ◽  
Martin Steiner ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
Endurance Exercise ◽  
Maximal Oxygen Uptake ◽  
Sodium Intake ◽  
Time Trial ◽  
Endurance Performance ◽  
Bicycle Ergometer ◽  
Time Trial Performance ◽  
Trial Performance ◽  
Nutrition Strategy

We investigated whether an athlete’s self-chosen nutrition strategy (A), compared with a scientifically determined one (S), led to an improved endurance performance in a laboratory time trial after an endurance exercise. S consisted of about 1000 mL·h–1 fluid, in portions of 250 mL every 15 min, 0.5 g sodium·L–1, 60 g glucose·h–1, 30 g fructose·h–1, and 5 mg caffeine·kg body mass–1. Eighteen endurance-trained cyclists (16 male; 2 female) were tested using a randomized crossover-design at intervals of 2 weeks, following either A or S. After a warm-up, a maximal oxygen uptake test was performed. Following a 30-min break, a 2.5-h endurance exercise on a bicycle ergometer was carried out at 70% maximal oxygen uptake. After 5 min of rest, a time trial of 64.37 km (40 miles) was completed. The ingested nutrition was recorded every 15 min. In S, the athletes completed the time trial faster (128 vs. 136 min; p ≤ 0.001) and with a significantly higher power output (212 vs. 184 W; p ≤ 0.001). The intake of fluid, energy (carbohydrate-, mono-, and disaccharide), and sodium was significantly higher in S compared with A (p ≤ 0.001) during the endurance exercise. In the time trial, only sodium intake was significantly higher in S (p ≤ 0.001). We concluded that a time trial performance after a 2.5-h endurance exercise in a laboratory setting was significantly improved following a scientific nutrition strategy.

Exercise training enhances leg vasodilatory capacity of 65-yr-old men and women

1990 ◽  
Vol 69 (5) ◽  
pp. 1804-1809 ◽  
Author(s):  
W. H. Martin ◽  
W. M. Kohrt ◽  
M. T. Malley ◽  
E. Korte ◽  
S. Stoltz
Keyword(s):  
Blood Flow ◽  
Body Weight ◽  
Exercise Training ◽  
Oxygen Uptake ◽  
Endurance Exercise ◽  
Maximal Oxygen Uptake ◽  
Statistical Significance ◽  
Tissue Loss ◽  
Leg Blood Flow ◽  
Endurance Exercise Training

To determine whether extremity vasodilatory capacity may be augmented in older persons by endurance exercise training, lower leg blood flow and conductance were characterized plethysmographically at rest and during maximal hyperemia in 9 men and 10 women aged 64 +/- 3 (SD) yr before and after 31 +/- 6 wk of walking and jogging at 70-90% of maximal oxygen uptake for 45 min 3-5 days/wk. Maximal oxygen uptake expressed as milliliters per kilogram per minute improved 25% in men and 21% in women (P less than 0.01). Maximal leg blood flow and conductance increased in all nine men by an average of 39 +/- 33 (P less than 0.001) and 42 +/- 44% (P less than 0.004), respectively. Results were more variable in women and achieved unequivocal statistical significance only for maximal blood flow (+33 +/- 54% for blood flow and +29 +/- 55% for conductance; P less than 0.02 and P = 0.05, respectively). Body weight and skinfold adiposity declined in both sexes (P less than 0.05). Enhancement of vasodilatory capacity was related to weight loss in men and adipose tissue loss in women (r = 0.61 and 0.51, respectively; P less than 0.05). There were no significant changes in exercise capacity, body weight, or maximal blood flow in four male and three female controls aged 66 +/- 4 yr. Thus adaptability of the lower limb circulation to endurance exercise training is retained to at least age 65 yr.

Polarized Versus High-Intensity Multimodal Training in Recreational Runners

2019 ◽  
Vol 14 (1) ◽  
pp. 105-112 ◽  
Author(s):  
Andrew J. Carnes ◽  
Sara E. Mahoney
Keyword(s):  
Body Composition ◽  
Oxygen Uptake ◽  
Endurance Training ◽  
Maximal Oxygen Uptake ◽  
High Intensity ◽  
Time Trial ◽  
Lower Volume ◽  
High Zone ◽  
Multimodal Training ◽  
Recreational Runners

Purpose: This study longitudinally compared changes in running performance (5-km time trial) and fitness (maximal oxygen uptake [VO2max] and body composition [BC]) between polarized training and CrossFit Endurance (CFE) in recreational runners. Methods: Participants (N = 21) completed 12 wk of CFE or polarized endurance training (POL). Both groups trained 5 d·wk−1. POL ran 5 d·wk−1, whereas CFE ran 3 d·wk−1 and performed CrossFit 3 d·wk−1 (run + CrossFit 1 d·wk−1). Intensity was classified as low, moderate, or high (zone 1, 2, or 3) according to ventilatory thresholds. POL was prescribed greater volume (295 [67] min·wk−1), distributed as 85%/5%/10% in Z1/Z2/Z3. CFE emphasized a lower volume (110 [18] min·wk−1) distribution of 48%/8%/44%. Results: POL ran 283 (75.9) min·wk−1 and 47.3 (11.6) km·wk−1, both exceeding the 117 (32.2) min·wk−1 and 19.3 (7.17) km·wk−1 in CFE (P < .001). The POL distribution (74%/11%/15%) had greater total and percentage Z1 (P < .001) than CFE (46%/15%/39%), which featured higher percentage Z3 (P < .001). Time trial improved −93.8 (40.4) s (−6.21% [2.16%]) in POL (P < .001) and −84.2 (65.7) s (−5.49% [3.56%]) in CFE (P = .001). BC improved by −2.45% (2.59%) fat in POL (P = .02) and −2.62% (2.53%) in CFE (P = .04). The magnitude of improvement was not different between groups for time trial (P = .79) or BC (P = .88). Both groups increased VO2max (P ≤ .01), but with larger magnitude (P = .04, d = 0.85) in POL (4.3 [3.6] mL·kg·min−1) than CFE (1.78 [1.9] mL·kg·min−1). Conclusions: Recreational runners achieved similar improvement in 5-km performance and BC through polarized training or CFE, but POL yielded a greater increase in VO2max. Extrapolation to longer distances requires additional research.

scholarly journals The Validity of Functional Threshold Power and Maximal Oxygen Uptake for Cycling Performance in Moderately Trained Cyclists

Sports ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 217 ◽  
Author(s):  
Arne Sørensen ◽  
Tore Kristian Aune ◽  
Vegar Rangul ◽  
Terje Dalen
Keyword(s):  
Oxygen Uptake ◽  
Maximal Oxygen Uptake ◽  
Local Level ◽  
Cycling Performance ◽  
Threshold Power ◽  
Mountain Bike ◽  
Mean Power ◽  
Valid Test ◽  
The Mean ◽  
And Performance

Cycling is a popular sport, and evaluation of the validity of tests to predict performance in competitions is important for athletes and coaches. Similarity between performance in sprints in mass-start bike races and in the laboratory is found, but, to our knowledge, no studies have investigated the relationship between laboratory measurements of maximal oxygen uptake (VO2max) and functional threshold power (FTP) with performance in official mass-start competitions. The purpose of this study was to evaluate the validity of a 20 min FTP test and VO2max as predictors for performance in an official mountain bike competition. Eleven moderately trained male cyclists at a local level participated in this study (age: 43 ± 5.1 years; height: 183.4 ± 5.4 m; weight: 84.4 ± 8.7 kg; body mass index: 25.1 ± 2.1). All subjects performed a 20 min FTP test in the laboratory to measure the mean power. In addition, the subjects completed an incremental test to exhaustion to determine VO2max. These two laboratory tests were analyzed together with the results from a 47 km mass-start mountain bike race, with a total elevation of 851 m. A significant relationship was found between the mean relative power (W/kg) for the 20 min FTP test and performance time in the race (r = −0.74, P < 0.01). No significant correlation was found between VO2max and cycling performance for these subjects (r = −0.37). These findings indicate that a 20 min FTP test is a more valid test for prediction of performance in mass-start bike races than a VO2max test for moderately trained cyclists.

scholarly journals A randomised four-intervention crossover study investigating the effect of carbohydrates on daytime profiles of insulin, glucose, non-esterified fatty acids and triacylglycerols in middle-aged men

2003 ◽  
Vol 89 (2) ◽  
pp. 207-218 ◽  
Author(s):  
Audrey E. Brynes ◽  
C. Mark Edwards ◽  
Mohammed A. Ghatei ◽  
Anne Dornhorst ◽  
Linda M. Morgan ◽  
...  
Keyword(s):  
Risk Factors ◽  
Fatty Acids ◽  
High Fat Diet ◽  
Assessment Model ◽  
High Fat ◽  
Middle Aged ◽  
High Carbohydrate ◽  
Esterified Fatty Acids ◽  
Sucrose Diet ◽  
Postprandial Insulin

Postprandial concentrations of glucose, insulin and triacylglycerols (TG) correlate to risk for CHD. Carbohydrates affect many metabolites that could have a potential effect on cardiovascular risk factors. The objective of the present study was to examine, using a randomised prospective study, the acute (day 1) and ad libitum medium-term (day 24) effects of four diets: a high-fat diet (HIGH-FAT; 50 % fat, >34 % monounsaturated fatty acids); a low-glycaemic index (GI) diet (LOW-GI; high-carbohydrate, low-GI); a high-sucrose diet (SUCROSE; high carbohydrate increase of 90 g sucrose/d); a high-GI diet (HIGH-GI; high-carbohydrate, high-GI). Daytime profiles (8 h) (breakfast, lunch and tea) of lipid and carbohydrate metabolism were completed during day 1 and day 24. Seventeen middle-aged men with one or more cardiac risk factors completed the study. There was no change from day 1 or between diets in fasting glucose, lipids or homeostatic assessment model (HOMA) on day 24. The HIGH-FAT compared with the three high-carbohydrate diets was associated with lower postprandial insulin and glucose but higher postprandial TG and non-esterified fatty acids (NEFA). There was a significant increase in the 6 h (15.00 hours) TG concentration (day 1, 2·6 (SEM 0·3) MMOL/L v. DAY 24, 3·3 (sem 0·3) mmol/l; P<0·01) on the SUCROSE diet. Postprandial HOMA (i.e. incremental area under the curve (IAUC) glucose (mmol/l per min)×IAUC insulin/22·5 (mU/l per min)) median changes from day 1 to day 24 were −61, −43, −20 and +31 % for the HIGH-FAT, LOW-GI, SUCROSE and HIGH-GI diets respectively. The HIGH-GI percentage change was significantly different from the other three diets (P<0·001). Despite being advised to maintain an identical energy intake there was a significant weight change (−0·27 (sem 0·3) kg; P<0·02) on the LOW-GI diet compared with the SUCROSE diet (+0·84 (sem 0·3) kg). In conclusion the HIGH-FAT diet had a beneficial effect on postprandial glucose and insulin over time but it was associated with higher postprandial concentrations of TG and NEFA. Conversely the HIGH-GI diet appeared to increase postprandial insulin resistance over the study period.

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