Hyperventilation did not measurably improve uphill sprints

Thomas Solomon, PhD

Pre-exercise hyperventilation sounds like a simple way to change the body’s acid-base balance before a hard effort. This study tested whether that physiological trick actually helped recreational athletes perform repeated steep treadmill sprints.

Reference: Fesseler et al. The effect of pre-exercise hyperventilation on repeated high-intensity inclined sprint performance. Experimental Physiology (2026) DOI: https://doi.org/10.1113/EP093393.

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Study snapshot

A quick, practical summary for runners and coaches.

Quick answer

This randomised crossover trialA study in which a group of people is randomised to receive BOTH the treatment and the no-treatment control, and the outcome of interest is measured before and after both. The “crossover” means that all participants complete all interventions (the control and the treatment), usually with a washout period in between. tested 30 seconds of rapid, deep breathing before repeated uphill treadmill sprints in 36 recreational athletes. The breathing protocol clearly lowered carbon dioxide levels, but it did not produce a measurable performance benefit. The study was small and used a fairly unusual laboratory test.

Key takeaways

  • Hyperventilation changed the participants’ breathing physiology but did not improve sprint performance.
  • The study was well controlled, but the small sampleN is how many participants or observations are analyzed. A bigger N usually means more precise estimates and more power (ability to detect a true effect). A smaller N results in a study that is less likely to detect a true effect (false negative/type II error) and is more likely to report false positives (type I error). Of course, a badly designed study is still bad even if it has a big N. and lack of a sham breathing conditionA fake version of a treatment or test used for comparison. It helps researchers check whether the real treatment has an effect beyond people’s expectations or the study setup itself. limit confidence.
  • Runners have little reason to add this exact protocol before hard uphill efforts.

How confident should we be?

Evidence confidence: Moderate

The randomisedRandomization means assigning people to different parts of a study (e.g., groups in a randomised controlled trial) by chance, not by choice. This helps make the groups similar at the start and reduces bias, so any differences you see are more likely due to the treatment, not background differences. In a crossover study, randomization usually decides the order in which each person gets the treatments (for example, Treatment A first then B, or B first then A). This way, order effects—like learning, fatigue, or simple time passing—are less likely to skew the results. crossoverCrossover means that all subjects completed all interventions (control and treatment) usually with a wash-out period in between. design and objective measurements strengthen the result. Confidence is limited by the small sample, lack of blindingBlinding is when people in a study don’t know which treatment they’re getting. It stops expectations or beliefs (from patients or researchers) from skewing the results. “Single-blind” means participants don’t know; “double-blind” means participants and researchers don’t know; “triple-blind” means that the participants, researchers, and data analysts are kept in the dark. The goal is simple: fair tests and trustworthy findings., and indirect relevance to endurance racing.

Bottom line

This 30-second hyperventilation routine did not help the participants run farther during repeated steep treadmill sprints. It is not a convincing addition to a runner’s warm-up.

Read the deep dive below to get a practical interpretation, the wider evidence, some actionable decisions, my thoughts, my rating of perceived scientific enjoyment, and the full study details (research question, study design, participants, methods, results, and the strengths & limitations).

Running science research reviews for endurance runners

The deep dive

The details behind the headline result, including the practical meaning, full findings, limitations, and my interpretation.

Practical meaning

What does this research mean for runners and coaches?

For runners

The study provides no good reason to deliberately hyperventilate before short, hard uphill efforts.

That conclusion applies to the exact protocol tested: 30 seconds of deep breathing at 60 breaths per minute immediately before each sprint. It does not show that every breathing technique is useless.

The direct relevance to marathon and ultra running is low. The participants completed brief, severe uphill efforts in a laboratory, not long-duration road races, mountain races, or ultras.

Trail and mountain runners may see a little more resemblance because the test involved steep running. Even then, the treadmill used a fixed speed and a progressively increasing incline. There was no uneven terrain, downhill running, prolonged climbing, or technical movement.

For coaches

The study does not support teaching this protocol as a performance aid.

The useful lesson is broader. A technique can change an interesting physiological measure without improving performance. Here, carbon dioxide levels moved exactly as planned. The runners did not.

Coaches should therefore treat hyperventilation as unproven rather than as a clever shortcut hiding in plain sight.

Evidence in context

What does the wider evidence say?

Small laboratory studies suggest that pre-exercise hyperventilation can alter acid–base balance, but its effects on high-intensity performance are inconsistent. Some cycling studies reported modest improvements during Wingate tests or repeated short sprints, particularly when hyperventilation was paired with longer recovery periods (Sakamoto et al. 2014, Leithäuser et al. 2016). Others found altered energy-system contributions without better overall power output, suggesting that the response depends on the breathing and exercise protocol (Dobashi et al. 2021).

How this study fits: This randomized crossover study strengthens the less enthusiastic side of the evidence. Thirty seconds of hyperventilation clearly lowered carbon dioxide but did not improve repeated uphill sprint performance in recreational athletes. It therefore adds a relatively practical running-based test rather than overturning earlier findings.

Practical decision

Should runners change anything?

No. There is no evidence from this study that runners should replace normal pre-effort breathing with deliberate hyperventilation.

Do not overreact if

  • Your breathing naturally quickens before a hard repetition.
  • You take a few deeper breaths as part of your normal preparation.

A sensible next step

Keep the pre-effort routine simple. Breathe normally, prepare for the effort, and let the hill create the heavy breathing on its own. It is more than qualified.

TIP: Never make any major changes to your training or lifestyle habits based on the findings of one study, especially if the study is small or provides low-quality evidence. Check whether other trials confirm the findings. If there is a meta-analysisA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment. on the topic, look at the effect sizeA standardised measure of the magnitude of an effect of an intervention. Unlike p-values, effect sizes show the size of the effect and how meaningful it might be. Common effect size measures include standardised mean difference (SMD), Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients., the variability between studies, and the quality of evidence.

Expert interpretation

My thoughts

Running science from Thomas Solomon at Veohtu

This is a useful negative study.

The researchers tested a plausible mechanism using a randomised crossover design. The breathing intervention clearly worked at the physiological level: the participants expelled more carbon dioxide, and their end-tidal carbon dioxide fell sharply.

The performance result was much less dramatic. Across the 3 sprints, the average elevation gain was 83.2 metres after hyperventilation and 84.3 metres during the control condition. The average difference was just over 1 metre in favour of the control condition, and the confidence intervalA measure of uncertainty used in Frequentist statistics. The 95% confidence interval is a plausible range of values within which the true value (e.g., the true treatment effect) would be found 95% of the time if the data were repeatedly collected in different samples of people. If this range of values (the confidence interval) crosses zero, there is little confidence that the average value is the true effect. If the confidence interval does not cross zero, we can be confident that the average value is the true effect. included both a modest disadvantage and a modest benefit.

That means the study did not prove that the true effect was exactly zero. It did show that this protocol produced no clear performance advantage under the test conditions.

The study also had practical value because the participants generally disliked the breathing routine, reported feeling worse after exercise, and did not think it helped. An intervention with no detectable benefit and poor user appeal is not exactly forming an orderly queue for adoption.

Nothing to see here; move along, move along.

The most interesting next step would be a larger study using a sham breathing condition and a more familiar running test. Until then, this looks more like an interesting physiological trick than a useful running tool.

My Rating of Perceived scientific Enjoyment

owlRPsE: 6/10

I experienced moderate scientific enjoyment because the randomised crossover design, registered protocolPre-registration is when a detailed description of a study plan is deposited in an open-access repository before collecting the study data. It promotes transparency and accountability and boosts research integrity. Without preregistration, it is easier for scientists to change outcomes after seeing the data, selectively report “exciting” results, or run many analyses and only show the ones that work, which can introduce bias and weaken the trustworthiness of the findings., objective measurements, and clear reporting made this a useful negative study. The small sample, lack of blinding, and limited relevance to endurance racing kept the scientific fireworks fairly modest.

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Read on for further details about the methods, results, strengths, limitations, and conflicts of interest.

Research question

What did the researchers ask?

The authors hypothesised that a short period of controlled hyperventilation immediately before exercise would improve performance during repeated high-intensity uphill sprints.

The proposed mechanism was simple enough. Rapid breathing lowers carbon dioxide and may temporarily make the blood more alkaline. In theory, that could delay some of the acidic shift that develops during very hard exercise and contributes to fatigue.

Study design

What type of study was this?

This study was a randomised, single-centre, controlled crossover trial.

Each participant completed both the hyperventilation condition and the control condition on separate days. This allowed the researchers to compare the 2 conditions within the same person, reducing the influence of differences in fitness, body size, and training status.

A crossover trial can test whether an intervention caused a difference under the study conditions. It does not remove every source of bias. The participants knew when they were hyperventilating, and the control condition did not include a sham breathing exercise.

Participants

Who took part?

The study included 36 recreational athletes: 18 male and 18 female participants.

The participants were aged 18 to 40 years, with a mean ageThe average of a set of numbers, calculated by summing all the values and dividing by the total number of values. of 24 years. They trained at least 3 times per week, had no relevant pre-existing medical conditions, and took no regular medication.

Their mean maximal oxygen uptakeVO2max is the maximal rate of oxygen consumption your body can achieve during exercise. It is a measure of cardiorespiratory fitness and indicates the size of your engine, i.e., your maximal aerobic power, which contributes to endurance performance. was 49.4 millilitres per kilogram per minute. This suggests that the group was recreationally fit, but the paper did not describe them as trained runners or elite endurance athletes.

Methods

What did the researchers do?

Who? 36 recreational athletes
What? 30 seconds at 60 breaths per minute
How long? 2 sessions, at least 48 hours apart

Each participant completed 2 laboratory sessions separated by at least 48 hours.

The participants first warmed up for 3 minutes at 4 kilometres per hour on a treadmill set to a 10% incline.

They then completed 3 uphill treadmill sprints, with 3 minutes of seated recovery between each effort.

Each sprint started at 12 kilometres per hour on a 10% incline. The incline increased by 2 percentage points every 30 seconds until it reached 16%, where it stayed until the participant stopped or the researchers ended the test for safety.

In the hyperventilation condition, the participants breathed deeply at 60 breaths per minute for the final 30 seconds before each sprint. A metronome controlled the rhythm.

In the control condition, the participants rested without performing the hyperventilation protocol.

The researchers measured total elevation gained, elevation gained during each sprint, carbon dioxide elimination, end-tidal carbon dioxide, blood lactate, blood pH, bicarbonate, base excess, and the participants’ opinions about the breathing method.

All 36 participants contributed to the main performance analysis. Some blood and breathing outcomes had missing observations at certain time points, and the source does not report why.

Main findings

What did the study find?

Carbon dioxide Markedly reduced
Sprint performance No detectable benefit
Blood lactate and pH No clear difference

The hyperventilation protocol clearly altered carbon dioxide handling.

The participants expelled more carbon dioxide during the 30-second breathing periods. Their end-tidal carbon dioxide also fell substantially before each sprint. These changes confirmed that the protocol successfully induced marked hypocapnia, meaning unusually low carbon dioxide levels.

The physiological change did not translate into a detectable performance benefit.

Across all 3 sprints, the participants gained:

  • 83.2 metres after hyperventilation.
  • 84.3 metres during the control condition.

The mean difference was 1.1 metres in favour of the control condition. The result was not statistically significantEvidence that a result is unlikely to be due to chance under a “no effect” model (or null hypothesis). Statistical significance is often judged by a p-value below 0.05 to flag that “something” is going on, but not how big or important that “something” is. One statistically significant result doesn’t mean proof; replication is needed. And, a statistically significant result doesn’t necessarily indicate clinical significance., and the confidence interval included both a modest disadvantage and a modest benefit.

No statistically significant difference was detected during any individual sprint. The estimated differences were small.

The researchers found a modest correlation between the condition difference in end-tidal carbon dioxide and cumulative elevation gain. This relationship did not appear during any individual sprint, so the authors treated it cautiously.

The amount of carbon dioxide expelled was not associated with sprint performance.

Blood lactate rose to about 12 millimoles per litre after sprint 1 and about 16 to 18 millimoles per litre after sprints 2 and 3.

Hyperventilation did not significantly change post-sprint blood lactate or blood pH. Bicarbonate was also similar between conditions.

Base excess was slightly lower during recovery after hyperventilation. The practical importance of that small difference is unclear.

The researchers did not measure blood pH immediately after the breathing period. They may therefore have missed a short-lived alkaline shift before each sprint.

The participants generally rated the routine poorly. They found it fairly easy to perform, but they did not like it, did not want to use it again, reported feeling worse after exercise, and would not recommend it to other athletes.

The authors concluded that this short, practical hyperventilation protocol did not improve repeated inclined sprint performance and should not be recommended for comparable real-world use.

What helps my confidence in the findings?

The strengths

  • The randomised crossover design allowed every participant to act as their own control.
  • The study included equal numbers of male and female participants.
  • The researchers objectively confirmed that the participants followed the breathing protocol.
  • The statistical model accounted for repeated measurements within each participant.
  • The trial was prospectively registered in the institution’s clinical trial registry.
  • The methods, outcomes, and statistical results were reported clearly.

What limits my confidence in the findings?

The limitations

  • The study included only 36 participants, and the paper does not report a prospective power calculationA power calculation is a way to figure out how many people or data points you need in a study so you can reliably spot a real effect if it exists. It balances four things: the size of the effect you care about, how much random variation there is, how strict you are about false alarms, and how likely you want to be to detect the effect. In plain terms: it helps you avoid running a study that’s too small to be useful or so big that it wastes time and money..
  • The participants and researchers could not be blinded, and the control condition did not include a sham breathing exercise.
  • The treadmill test was bespoke and does not closely match road racing, trail racing, or ultramarathon performance.
  • The participants were young recreational athletes rather than confirmed competitive runners.
  • The study tested only 1 breathing protocol.
  • The researchers did not measure blood pH immediately after hyperventilation.
  • Several blood outcomes had missing observations, particularly later in the protocol.
  • The study examined a short laboratory response rather than training adaptation or race performance.

Funding and conflicts

Who funded the study?

The study received funding from the German Aerospace Center and the German Federal Ministry for Economic Affairs and Climate Action.

Open-access publication was partly supported by Charité Universitätsmedizin Berlin.

The authors declared no conflicts of interestA conflict of interest happens when a person or group has a personal, financial, or professional interest that could influence their judgment. It does not always mean they did something wrong. But it can create bias or make others question whether the decision or result is fully fair and trustworthy.. The paper did not report funding from a company selling breathing equipment or the intervention being tested.

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