Chlorella, blood lactate and oxygen pulse in young cyclists
What it found
In 20 young healthy adults, 2 days of 6 g/day chlorella lowered blood lactate and raised O2 pulse during cycling, but did not improve maximal oxygen uptake or peak work rate.
The trial compared chlorella with a placebo in the same people.
What they found
Studies in people
Blood lactate lower
During submaximal cycling, average blood lactate was lower after chlorella (2.67 mmol/L) than after placebo (3.05 mmol/L). After the maximal test, lactate was also lower with chlorella (11.56 mmol/L) than placebo (12.79 mmol/L).
O2 pulse higher
O2 pulse was higher after chlorella during submaximal cycling (13.1 vs 12.6 mL/beat) and at maximal intensity (17.2 vs 16.7 mL/beat).
No change in VO2max
There was no difference between chlorella and placebo in maximal oxygen uptake or maximal work rate. Oxygen consumption and respiratory exchange ratio during submaximal cycling also did not differ.
Heart rate
Heart rate during submaximal cycling was slightly lower with chlorella (131 b/min) than placebo (134 b/min), but this difference was not statistically significant.
Side effects
One participant reported a grassy taste when burping after chlorella. All participants reported complete adherence to the supplementation.
What the authors conclude
“The novel findings of this study indicate that 2 days of 6 g/day chlorella supplementation significantly reduces the blood lactate response and increases O 2 pulse during a 20 min submaximal cycle and V ˙ O 2 max .”
Also in their conclusions
- They conclude that 2 days of 6 g/day chlorella supplementation lowers the blood lactate response and increases O2 pulse during submaximal and maximal cycling, but does not improve maximal oxygen uptake or maximal work rate.
- They say future research should investigate chlorella supplementation in an athlete population and focus on the mechanisms behind the changes in blood lactate and O2 pulse.
How it was done
Chlorella has been reported to improve maximal oxygen uptake after longer supplementation periods, but little was known about its effects at submaximal exercise intensities or after shorter supplementation. The authors wanted to see whether a shorter, 2-day loading period could still have an effect.
Twenty young healthy adults (16 males, 4 females, average age 22) took 6 g/day of chlorella or a placebo for 2 days each, in a randomised, double-blinded, cross-over design with a one-week washout between trials. After each supplementation period they did a 20-minute submaximal cycle at 40% of their maximal work rate, followed by an incremental test to fatigue. Blood lactate, heart rate, oxygen consumption, O2 pulse, respiratory exchange ratio and maximal work rate were compared between conditions.
What it can’t tell you
- The study lasted only 2 days, so it cannot show what would happen with longer supplementation.
- The participants were young, healthy and mostly students, not trained cyclists, so the results may not apply to other groups.
- The researchers did not measure vasodilation or nutritional status, so they cannot say why the changes occurred or whether they would appear in people with different nutrient levels.
Who paid
- Conflicts
- The authors declare no conflict of interest.
- Authors work at
- University College London, UK
The paper
- Title
- Chlorella Supplementation Reduces Blood Lactate Concentration and Increases O 2 Pulse during Submaximal and Maximal Cycling in Young Healthy Adults
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Licence
- CC BY. Words in quotation marks are the authors’; the rest is our summary.
- Cite
- White H, Gurney T (2024). Chlorella Supplementation Reduces Blood Lactate Concentration and Increases O 2 Pulse during Submaximal and Maximal Cycling in Young Healthy Adults. Nutrients. doi:10.3390/nu16050697Free full textPubMed 38474825DOI
Summary written 29 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error