Sodium phosphate and 20 km cycling performance
What it found
In 20 trained male cyclists, taking sodium phosphate for four days did not change 20 km time-trial times or responses during steady cycling.
It did raise breathing rate, respiratory exchange ratio, perceived effort and blood lactate during the time trial.
What they found
Studies in people
Steady cycling responses
During cycling at 65% V̇O2max, sodium phosphate had no effect on the physiological responses measured.
Time-trial performance
Time-trial performance was the same with sodium phosphate and placebo: 32.8 ± 2.3 minutes versus 32.8 ± 2.2 minutes.
Breathing during time trial
Compared with placebo, sodium phosphate increased minute ventilation during the time trial by an average of 3.81 L per minute.
Respiratory exchange ratio
Sodium phosphate raised the respiratory exchange ratio during the time trial by an average of 0.020 compared with placebo.
Perceived effort
Ratings of perceived exertion during the time trial were higher with sodium phosphate than with placebo, by an average of 0.39.
Blood lactate
After the time trial, blood lactate concentration was higher with sodium phosphate than with placebo, by an average of 1.06 mmol per litre.
What the authors conclude
“SP supplementation has no significant effects on submaximal physiological responses or 20 km time-trial performance.”
Also in their conclusions
- They conclude that sodium phosphate supplementation has no significant effects on submaximal physiological responses or 20 km time-trial performance.
How it was done
The authors wanted to see whether sodium phosphate supplementation affects physiological responses to submaximal exercise and 20 km cycling time-trial performance.
Twenty endurance-trained male cyclists completed two supplementation trials separated by a 14-day washout, in a randomised, double-blind, crossover design. Each trial involved 10 minutes of cycling at 65% V̇O2max followed by a 20 km time trial. For four days before each trial, they took 50 mg per kg of fat-free mass per day of either sodium phosphate or a placebo.
What it can’t tell you
- We summarised it from the abstract only.
- The study lasted only four days of supplementation, so it cannot show what longer use might do.
- It included 20 endurance-trained male cyclists, so the results may not apply to other people.
Who paid
- Authors work at
- St. Mary's University, UK
The paper
- Title
- The Effects of Sodium Phosphate Supplementation on Physiological Responses to Submaximal Exercise and 20 km Cycling Time-Trial Performance
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Abstract only
- Cite
- Brown JA, Glaister M (2019). The Effects of Sodium Phosphate Supplementation on Physiological Responses to Submaximal Exercise and 20 km Cycling Time-Trial Performance. Journal of dietary supplements. doi:10.1080/19390211.2018.1472708PubMed 29985679DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error