Researchers from the Athletic Performance Centre at KU Leuven subjected 27 moderately trained participants to a so-called Sprint Interval Training, which took the form of three short but intense cycling sessions per week. To assess the participants’ performance in different conditions, the researchers included both workouts in normal oxygen conditions and workouts in low oxygen conditions like the ones found at high altitudes (ca. 2,750m). Before each workout, they gave the participants a nitrate supplement or a placebo.
Only five weeks into the experiment, the researchers already observed changes in the muscle fibre composition in all participants. However, the increase in the so-called fast-oxidative muscle fibres was more pronounced in participants who had been taking nitrate supplements and training in low oxygen conditions.
“This is probably the first study to demonstrate that a simple nutritional supplementation strategy can impact on training-induced changes in muscle fibre composition,” says Professor Peter Hespel from the Athletic Performance Centre.
The findings are particularly interesting for athletes competing in conditions with limited amounts of oxygen. In fact, exercising at high altitudes – and therefore in low oxygen conditions – has become a popular training strategy among athletes, despite the uncertainties about such methods.
Performing intense workouts in low oxygen conditions requires a high input from specific muscle fibres to sustain the power. Could enhancing these muscle fibre through nutritional intake boost exercise performance?
“That is actually still a question mark,” says Professor Hespel. “In any case, we don’t recommend a consistent high-dose nitrate intake combined with training until we’re absolutely sure that it’s safe.”
Research into how dietary supplements may give athletes that much-wanted competitive edge is still in the early stages. “Further research will have to show whether adding nitrate-rich vegetables to athletes’ daily diet can help improve their exercise performance in the long run,” Professor Hespel concludes.