Daily training with high carbohydrate availability increases exogenous carbohydrate oxidation during endurance cycling.

@article{Cox2010DailyTW,
  title={Daily training with high carbohydrate availability increases exogenous carbohydrate oxidation during endurance cycling.},
  author={Gregory R. Cox and Sally A. Clark and Amanda J. Cox and Shona L. Halson and Mark Hargreaves and John A. Hawley and Nikki A. Jeacocke and Rodney J Snow and Wee Kian Yeo and Louise M. Burke},
  journal={Journal of applied physiology},
  year={2010},
  volume={109 1},
  pages={
          126-34
        }
}
We determined the effects of varying daily carbohydrate intake by providing or withholding carbohydrate during daily training on endurance performance, whole body rates of substrate oxidation, and selected mitochondrial enzymes. Sixteen endurance-trained cyclists or triathletes were pair matched and randomly allocated to either a high-carbohydrate group (High group; n = 8) or an energy-matched low-carbohydrate group (Low group; n = 8) for 28 days. Immediately before study commencement and… 

Figures and Tables from this paper

Carbohydrate dependence during prolonged simulated cycling time trials

NA impaired cycling TT performance lasting 120 min, cycling TTs lasting from 60 to 120 Min are CHO dependent, and there is an obligatory use of lipid-based fuels in TTslasting 1–2 h.

Beneficial metabolic adaptations due to endurance exercise training in the fasted state.

F is more effective than CHO to increase muscular oxidative capacity and at the same time enhances exercise-induced net IMCL degradation and prevented drop of blood glucose concentration during fasting exercise.

Effect of carbohydrate intake and physical exercise on glycogen concentration

Maltodextrin supplementation was effective in increasing skeletal muscle and kidney glycogen stores in rats submitted to aerobic exercise, as well as in blood glucose and blood lactate.

Sports Drink Intake Pattern Affects Exogenous Carbohydrate Oxidation during Running

Ingestion of a larger volume of carbohydrate solution at less frequent intervals during prolonged submaximal running increased exogenous carbohydrate oxidation rates, and neither drinking pattern resulted in increased markers of GI discomfort to a severe level.

Sustained Exposure to High Carbohydrate Availability Does Not Influence Iron-Regulatory Responses in Elite Endurance Athletes.

It appears that variations in serum ferritin concentration and ambient temperature, rather than dietary CHO, are associated with increased hepcidin concentrations 3 hr postexercise.

Performance effects of periodized carbohydrate restriction in endurance trained athletes – a systematic review and meta-analysis

  • K. GejlL. Nybo
  • Education
    Journal of the International Society of Sports Nutrition
  • 2021
It is concluded that periodized CHO restriction does not per se enhance performance in endurance-trained athletes and different approaches to CHO periodization across studies are discussed with a focus on identifying potential physiological benefits.

Dietary Manipulations Concurrent to Endurance Training

Over the past 20 years, research has suggested that strategically reducing carbohydrate availability during an athlete’s training can modify the metabolic responses in lieu of simply maintaining a high CHO diet, yet data showing a direct performance benefit is still unclear.

Carbohydrates for training and competition

Whether implementing additional “train-low” strategies to increase the training adaptation leads to enhanced performance in well-trained individuals is unclear.

The new carbohydrate intake recommendations.

  • A. Jeukendrup
  • Education
    Nestle Nutrition Institute workshop series
  • 2013
Findings resulted in new recommendations that are dependent on the duration and intensity of exercise and not only specify the quantity of carbohydrate to be ingested but also the type.

Feeding Tolerance, Glucose Availability, and Whole-Body Total Carbohydrate and Fat Oxidation in Male Endurance and Ultra-Endurance Runners in Response to Prolonged Exercise, Consuming a Habitual Mixed Macronutrient Diet and Carbohydrate Feeding During Exercise

Endurance and ultra-endurance runners can attain relatively high rates of whole-body fat oxidation during exercise in a post-prandial state and with carbohydrate provisions during exercise, despite consuming a mixed macronutrient diet.
...

References

SHOWING 1-10 OF 56 REFERENCES

The effects of carbohydrate loading on muscle glycogen content and cycling performance.

Muscle glycogen contents were similar at the end of the 3-hr trial, indicating a greater utilization of glycogen when subjects were CHO loaded, which may have been responsible for their improved cycling performance.

Carbohydrate balance in competitive runners during successive days of intense training.

When CHO intake was only approximately 50% of the energy requirements there was a marked depletion of muscle glycogen stores, particularly in type I fibers, and a concomitant decrease in running economy and increased perception of fatigue.

Skeletal muscle adaptation and performance responses to once a day versus twice every second day endurance training regimens.

While selected markers of training adaptation were enhanced with twice a day training, the performance of a 1-h time trial undertaken after a 60-min steady-state ride was similar after once daily or twice every second day training programs.

Dietary carbohydrate, muscle glycogen, and exercise performance during 7 d of training.

For cyclists and runners, consuming a moderate-carbohydrate diet over 7 d of intense training reduces muscle glycogen but has no apparent deleterious effect on training capability or high-intensity exercise performance.

Muscle metabolism during prolonged exercise in humans: influence of carbohydrate availability.

The data suggest that carbohydrate ingestion may increase endurance capacity, at least in part, by improving muscle energy balance and there was a small but significant increase in muscle inosine monophosphate levels in both trials.

Effect of training in the fasted state on metabolic responses during exercise with carbohydrate intake.

Although there was a decrease in exercise-induced glycogen breakdown and an increase in proteins involved in fat handling after fasting training, fat oxidation during exercise with carbohydrate intake was not changed and fat oxidation rates during exercise were not altered by training.

Effect of carbohydrate or carbohydrate plus medium-chain triglyceride ingestion on cycling time trial performance.

It is demonstrated that carbohydrate ingestion during exercise improves 100-km TT performance compared with a sweet placebo, but the addition of MCT does not provide any further performance enhancement.

Carbohydrate-electrolyte feedings and 1 h time trial cycling performance.

It was concluded that CHO-E consumption throughout a 1-h time trial, following a pre-exercise dietary regimen designed to optimize glucose availability, did not improve time or power output to a greater degree than P in well-trained cyclists.

Effect of timing of carbohydrate ingestion on endurance exercise performance.

Performance was improved, relative to the control trial, only when carbohydrate was ingested throughout exercise, despite increases in plasma glucose levels and plasma insulin levels similar to CHO-7.

High rates of muscle glycogen resynthesis after exhaustive exercise when carbohydrate is coingested with caffeine.

It is provided the first evidence that in trained subjects coingestion of large amounts of Caff (8 mg/kg BM) with CHO has an additive effect on rates of postexercise muscle glycogen accumulation compared with consumption of CHO alone.
...