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Carbon monoxide supplementation: evaluating its potential to enhance altitude training effects and cycling performance in elite athletes.

PMID 39236115 (2024): altitude — VO₂max, Time-trial performance (study note for endurance athletes).

Last updated/Feb 23, 2026, 10:34 PM

Study note • PMID 39236115

Carbon monoxide supplementation: evaluating its potential to enhance altitude training effects and cycling performance in elite athletes.

Journal of applied physiology (Bethesda, Md. : 1985)2024 • DOI 10.1152/japplphysiol.00469.2024
Evidence C60/100
Action 2: Consider

Worth trying if it fits your goal and context.

ELI5

In plain language

Altitude training is a cornerstone for endurance athletes for improving blood variables and performance, with optimal effects observed at approximately 2,300-2,500 meters above sea level (m.a.s.l.). (controlled study; elite cyclists).

The abstract doesn’t indicate a clear change in VO₂max, Time-trial performance under the tested conditions. Treat this as a signal, not a guarantee; confirm methods and context in the full paper.

Takeaways

What the abstract suggests

  • Study question: Altitude training is a cornerstone for endurance athletes for improving blood variables and performance, with optimal effects observed at approximately 2,300-2,500 meters above sea level (m.a.s.l.).
  • The abstract doesn’t indicate a clear change in VO₂max, Time-trial performance under the tested conditions.
  • Population: elite cyclists.
  • Protocol cues (title/abstract): 100 m.

Protocol

Protocol (as reported)

  • Intervention/exposure: altitude (vs comparison group).
  • Dose/time/duration cues in abstract/title: 100 m.
  • Outcomes: VO₂max, Time-trial performance.
  • Replication note: abstracts often omit adherence and timing; confirm details before changing training or supplementation.

Fit

Who it helps, and who should skip it

Who it helps

  • Athletes similar to the study population (elite cyclists) working on altitude.
  • Athletes who can measure VO₂max, Time-trial performance with a repeatable workout or time-trial effort.

Who should skip

  • If you have symptoms or conditions that make the intervention risky, get professional guidance.
  • If you’re near race day and can’t safely test, defer the experiment.

Methods

What the study actually did

  • Design: controlled study.
  • Population: elite cyclists.
  • Comparator: comparison group.
  • Outcomes measured: VO₂max, Time-trial performance.
  • Protocol cues mentioned: 100 m.
  • Source: PubMed PMID 39236115 (2024) — Journal of applied physiology (Bethesda, Md. : 1985).

Results excerpt

What the abstract reports

Cycling performance determinants improved more with CO inhalation at moderate altitude compared to sea-level training, whereas there were no differences in submaximal and maximal performance measures compared to moderate-altitude training alone.

Note: excerpts are short; for full context, read the paper.

Limits

Limitations & bias

  • Abstract-only summaries can miss critical details (population, protocol, adherence, and context).
  • Single studies often don’t generalize to your event, history, and training load; treat results as a starting point.
  • If your context differs (elite vs recreational; cycling vs running), adjust expectations and be conservative.
  • This is performance information, not medical advice.

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Sources