Liver and Muscle Glycogen Use During Exercise. Clinical Trial
| Verified date | August 2015 |
| Source | Northumbria University |
| Contact | n/a |
| Is FDA regulated | No |
| Health authority | United Kingdom: Research Ethics Committee |
| Study type | Interventional |
Carbohydrate is stored in the body as glycogen, which is mainly found in the liver and
muscle. During endurance exercise, muscle glycogen is used as fuel for the working muscles
and liver glycogen is broken down to provide glucose to maintain blood glucose (sugar)
levels. Both liver and muscle glycogen are important for the ability to perform
intense/prolonged endurance exercise. Therefore, nutritional strategies which can maximise
the availability of glycogen in muscle and liver can benefit endurance exercise capacity.
The carbohydrates typically found in sports drinks are glucose and sometimes fructose. If
glucose only is ingested during exercise, then the maximum rate at which can be absorbed
from the intestine into the blood stream is ~1 g/min. However, if different sources of
carbohydrate (fructose) are used, which are absorbed through a different pathway, absorption
of carbohydrate can be up to ~1.8 g/min. With more carbohydrate available as a fuel, this
translates into an improvement in performance.
Sucrose is a naturally occurring sugar that is made up of a single glucose and single
fructose molecule. Therefore, theoretically, this can use the two different pathways of
absorption and also maximise carbohydrate delivery. It is not yet known however, what impact
this has on our liver and muscle glycogen stores during exercise. Therefore the aim of this
study is to assess whether sucrose ingestion influences liver and muscle glycogen depletion
during endurance exercise.
| Status | Completed |
| Enrollment | 14 |
| Est. completion date | April 2015 |
| Est. primary completion date | September 2014 |
| Accepts healthy volunteers | Accepts Healthy Volunteers |
| Gender | Male |
| Age group | 18 Years to 35 Years |
| Eligibility |
Inclusion Criteria: - Healthy - Male - 18 - 35 years of age - Endurance trained cyclist/triathlete - VO2 max = 50 ml/kg/min Exclusion Criteria: - Use of medication - Smoking - Metabolic disorders |
Allocation: Randomized, Intervention Model: Crossover Assignment, Masking: Double Blind (Subject, Investigator, Outcomes Assessor), Primary Purpose: Basic Science
| Country | Name | City | State |
|---|---|---|---|
| United Kingdom | Northumbria University | Newcastle upon Tyne | Tyne and Wear |
| Lead Sponsor | Collaborator |
|---|---|
| Javier Gonzalez, PhD | Maastricht University, Sugar Nutrition, UK, University of Newcastle Upon-Tyne |
United Kingdom,
| Type | Measure | Description | Time frame | Safety issue |
|---|---|---|---|---|
| Primary | Change in liver glycogen concentration | The change in liver glycogen concentration will be determined pre-to-post 3 h of exercise using 13C magnetic resonance spectroscopy. | 3 hours | No |
| Secondary | Plasma glucose concentration. | Plasma glucose concentrations will be determined every 30 min during 3 h of exercise. | 3 hours | No |
| Secondary | Plasma lactate concentration | Plasma lactate concentrations will be determined every 30 min during 3 h of exercise. | 3 hours | No |
| Secondary | Plasma non-esterified fatty acid concentration | Plasma non-esterified fatty acid concentrations will be determined every 30 min during 3 h of exercise. | 3 hours | No |
| Secondary | Indirect calorimetry | Measurements of oxygen consumption, carbon dioxide production and respiratory exchange ratio through indirect calorimetry measured every 30 minutes during exercise. | 3 hours | No |
| Secondary | Muscle glycogen concentration | The change in muscle glycogen concentration will be determined pre-to-post 3 h of exercise using 13C magnetic resonance spectroscopy. | 3 hours | No |
| Secondary | Change in intramyocellular lipid concentration | The change in intramyocellular lipid concentration will be determined pre-to-post 3 h of exercise using 1H magnetic resonance spectroscopy. | 3 hours | No |