Sodium phosphate loading and cycling performance in trained men
What it found
Taking sodium phosphate twice improved peak oxygen use more than taking it once, in nine trained male cyclists.
Power output during a cycling test also rose after the second round.
What they found
Studies in people
Cycling time-trial speed
Ride times ranged from 55.3 to 56.5 minutes. Times were about 60 to 70 seconds shorter after sodium phosphate, but this was not clearly different from baseline or placebo.
Power output while cycling
After the second sodium phosphate round, riders produced more power than with the placebo at the 250-kJ and 500-kJ marks of the cycling test.
Peak oxygen uptake
Peak oxygen use rose by 3.5 to 4.3% after the first sodium phosphate round compared with baseline and placebo. It rose further, by 7.1 to 7.7%, after the second round.
What the authors conclude
- They conclude that taking sodium phosphate again, either 15 or 35 days after the first round, can add to its effect on peak oxygen use.
- The authors suggest it may also improve cycling time-trial performance.
How it was done
Earlier work on sodium phosphate supplements had not looked at what happens when people take repeated rounds of it. The authors wanted to see if extra doses added any benefit for cycling speed and oxygen use.
Nine trained male cyclists took either 50 mg per kg of fat-free mass each day of tribasic sodium phosphate or a sugar and salt placebo for six days. They completed a 1,000-kJ cycling test and an oxygen test before and after each phase. A 14-day break separated the phases, with two sodium phosphate rounds and one placebo round done in mixed order.
What it can’t tell you
- We summarised it from the abstract only.
- Only nine men took part, so the results may not apply to women or casual exercisers.
- The study measured short-term sports performance, not long-term health effects of sodium phosphate.
Who paid
- Authors work at
- University of Western Australia, Australia
The paper
- Title
- Effect of repeated sodium phosphate loading on cycling time-trial performance and VO2peak
- Type
- Study
- Evidence
- Studies in people
- Summarised from
- Abstract only
- Cite
- Brewer CP, Dawson B, Wallman KE, Guelfi KJ (2013). Effect of repeated sodium phosphate loading on cycling time-trial performance and VO2peak. International journal of sport nutrition and exercise metabolism. doi:10.1123/ijsnem.23.2.187PubMed 23114686DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error