The study was designed to indirectly understand muscle
glycogen utilization during prolonged exercise when either
glucose, fructose, or water is ingested. Eight trained
adult males exercised on a cycle ergometer at 58±7% of V02
max for 2 h on 2-4 occasions. At 0 minutes of exercise and
at 30-minute intervals throughout the exercise, the
subjects ingested 200mL of fluid containing either glucose,
fructose, or plain water in a double-blind, randomized
fashion. The carbohydrate (CHO) fluid concentration was
based on each subject's body weight (BW): Ig CHO X kg⁻¹ BW
X L⁻¹ water and ranged from 5.8-9.2% (average=7.5%) of BW.
Blood samples were collected from subjects at rest and
immediately prior to fluid ingestion during exercise and
analyzed for hematocrit, hemoglobin, and plasma levels of
glucose, lactate, and pyridoxal 5'-phosphate (PLP). ANOVA
showed no significant difference among treatments at any
time of exercise for mean plasma lactate and PLP levels (p > 0.05). Although not significant, mean plasma lactate and PLP concentrations tended to be lower when glucose was
consumed as compared to fructose and water. The mean
plasma glucose level, however, uas significantly different
among treatments at specific time points of exercise (p < 0.05). During exercise, mean plasma glucose decreased, and there was a higher plasma glucose level when glucose and
fructose fluids were ingested as compared to water. At 60
minutes of exercise, this difference uas evident for both
glucose and fructose ingestion (p < 0.05). At 90 and 120
minutes of exercise, fructose ingestion produced a
significantly higher mean plasma glucose level than either
water or glucose ingestion (p < 0.05). It is hypothesized
that the higher plasma glucose levels provided a greater
blood glucose supply to working muscles, thereby sparing
muscle glycogen stores. The findings indicate that for the
long-term exerciser, consumption of a 5.8-9.2% fructose
solution may promote less muscle glycogen utilization than
either glucose or water, thereby possibly increasing
endurance. / Graduation date: 1986
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/27205 |
| Date | 17 January 1986 |
| Creators | Seitz, Julia Ann |
| Contributors | Leklem, James E. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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