Cordyceps Boosts Oxygen Uptake and Reaction Times

A single 1-gram dose of Cordyceps militaris extract taken before exercise significantly improved post-exercise reaction time and increased resting oxygen consumption in a new randomized trial. The study, published in *PLoS One*, offers a direct look at how this popular fungus might provide an acute cognitive and metabolic edge.

How the Cordyceps Study Was Conducted

Researchers Hamidreza Farzan and Maryam Koushkie Jahromi from Shiraz University designed a rigorous test. They recruited 12 recreationally active young men and had them perform two maximal cycling tests to exhaustion. The trials were separated by a 7-day washout period.

In a double-blind, crossover design, each participant took either 1 gram of a standardized Cordyceps militaris extract or a cornstarch placebo 30 minutes before the test. The order was randomized. The team measured cognitive performance using a Stroop test—a common measure of reaction time and mental focus—both before and 3 minutes after the exhaustive exercise. They also tracked physiological markers including oxygen uptake (VO₂), blood glucose, blood pressure, and heart rate.

Faster Reactions After Exercise, Higher Resting Metabolism

The most striking finding was in cognitive performance. While both groups saw improved reaction times from pre- to post-exercise—a known effect of acute exercise—the Cordyceps group finished with a clear advantage. Post-exercise reaction times were 963.92 milliseconds for the Cordyceps group versus 1034.33 milliseconds for the placebo group. This 70-millisecond difference was statistically significant (p=0.042) and represented a large effect size (d=0.88). Accuracy was near-perfect in both groups.

Separately, the supplement triggered a pronounced increase in resting metabolism. Before exercise, resting oxygen consumption was 0.37 liters per minute in the Cordyceps condition compared to 0.24 L/min with placebo—a 54% relative increase. This suggests the fungus prompted a state of elevated metabolic activity even before the physical challenge began.

What Didn’t Change

Importantly, the supplement did not act as a stimulant or performance-enhancer in the traditional sense. It did not alter peak VO₂ during the maximal test. Blood glucose, blood pressure, and heart rate responses were also indistinguishable from placebo. This points to a specific, targeted effect on cognitive speed and basal metabolic rate, rather than a broad systemic stimulation.

The authors note in their conclusion: “This suggests CM exerts an acute cognitive benefit independent of exercise modulation.” The benefit appears to be a direct effect on brain function, not a secondary result of improved physical output.

Practical Implications for Endurance Athletes

For the informed fitness enthusiast, this study offers actionable insights. The acute use of Cordyceps militaris could be considered for scenarios requiring sharp mental focus immediately following hard training—such as making quick tactical decisions in a race environ (iron bisglycinate)ment, or needing to maintain concentration for skill work after a fatiguing session.

The elevation in resting VO₂ is also intriguing. While the study did not explore the mechanism, a higher resting metabolic rate could be linked to improved cellular energy production. This aligns with the broader interest in mitochondrial health and metabolic efficiency that underpins effective zone 2 training. Whether this acute metabolic spike translates to chronic adaptations or improved efficiency during low-intensity exercise remains an open question.

It is critical to note the study’s limitations: a small sample of young, recreationally active men, and a single, high dose. The effects of chronic supplementation, different dosing, or use in other populations are unknown. The cognitive test was also administered post-exercise, not during the activity itself.

A Targeted Tool, Not a Magic Bullet

This research, available in full via its PubMed entry (PMID: 42455764) or DOI: 10.1371/journal.pone.0351725, clarifies the potential role of Cordyceps militaris. It is not a substitute for foundational training methods proven to build endurance and metabolic health, such as the structured approaches discussed in our analyses of HIIT versus moderate-intensity exercise.

Instead, it may serve as a specific, acute intervention for moments where mental clarity after physical exertion is paramount. The combination of faster reaction times and a higher resting metabolic rate, without cardiovascular stimulation, presents a unique profile. For athletes focused on the fine margins, this evidence-based nuance could be a valuable addition to their toolkit.