Breathing air with less oxygen through a mask (simulated altitude) makes your muscles get less oxygen during exercise than being at real high altitude, even when the oxygen level in the air is the same.

Scientific Claim

Normobaric hypoxia (FiO₂ = 15.9%) induces a moderate to very large reduction in muscle oxygenation (SmO₂) compared to hypobaric hypoxia at equivalent altitude (2,320 m), with effect sizes of 0.79–2.26, suggesting impaired muscle reoxygenation despite identical inspired oxygen levels.

Original Statement

“Compared to HH, NH showed a moderate reduction in the inter-set rest-HR (ES > 0.80), maxLac (ES > 1.01) and SmO₂ (ES > 0.79) at both rest intervals. ... moderate to very large reductions in SmO₂T were observed in NH during both training sessions.”

From study:Inter-set rest configuration effect on acute physiological and performance-related responses to a resistance training session in terrestrial vs simulated hypoxia

Evidence Quality Assessment

Claim Status

appropriately stated

Study Design Support

Design supports claim

Appropriate Language Strength

definitive

Can make definitive causal claims

Assessment Explanation

The RCT design with direct, objective measurement of SmO₂ via NIRS and large effect sizes supports definitive causal claims about the differential impact of hypoxia types on muscle oxygenation.

Evidence from Studies

Supporting (1)

Inter-set rest configuration effect on acute physiological and performance-related responses to a resistance training session in terrestrial vs simulated hypoxia

Randomized Controlled Trial

Human

2022

Even though both types of low-oxygen environments have the same amount of oxygen in the air, the study found that breathing low-oxygen air at normal pressure (normobaric) made muscles less oxygenated than being at high altitude (hypobaric), meaning muscles had a harder time recovering between sets.

Contradicting (0)

No contradicting evidence found

Source Study

Inter-set rest configuration effect on acute physiological and performance-related responses to a resistance training session in terrestrial vs simulated hypoxia

Score: 49

DOI: 10.7717/peerj.13469

Similar Assertions

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