Medical expert of the article
New publications
Fructose during exercise
Last reviewed: 12.04.2020
All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.
We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.
If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.
Some athletes take fructose tablets during exercise. Since fructose has a low glycemic index (it causes a weaker reaction of blood glucose and insulin), athletes can mistakenly consider it to be the best source of energy.
Murrey et al. Studied the physiological, sensory responses and performance indicators for taking 6% solutions of glucose, sucrose and fructose during exercise. Levels of insulin in the blood, as expected, were lower when taking fructose. But fructose was associated with large gastrointestinal disorders, stronger stress and higher levels of serum cortisol, indicating greater physiological stress than glucose and sucrose. The time shown in the bicycle race with the intake of sucrose and glucose was also significantly higher than when taking fructose.
The lower level of glucose in the blood, associated with the intake of fructose, explains why the indices are not improving. The metabolism of fructose occurs predominantly in the liver, where it is converted into glycogen. Perhaps fructose can not turn into glucose and release quickly enough to supply the working muscles with adequate energy. In contrast, blood glucose levels are maintained or increased by the consumption of glucose, sucrose or glucose polymers. It is shown that they improve performance and are the preferred carbohydrates for sports drinks.
More frequent cases of gastrointestinal disorders (bloating, spasms and diarrhea), caused by the intake of large amounts of fructose, can be explained by slower absorption of fructose compared with glucose.
[