Even if the air has the same oxygen level, being at real high altitude makes your body respond differently to weightlifting than breathing the same air through a mask—your muscles get more oxygen, you produce more lactic acid, and your heart works harder.
Scientific Claim
The acute physiological response to resistance training under normobaric hypoxia is not equivalent to that under hypobaric hypoxia despite identical FiO₂, with NH producing lower muscle oxygenation, lower lactate accumulation, and lower rest heart rate, suggesting barometric pressure independently influences metabolic and cardiovascular responses.
Original Statement
“For an equivalent FiO2, the type of hypoxia (terrestrial vs simulated) affects the physiological response to a traditional hypertrophy-oriented RT session. ... differences detected between HH and NH suggest an independent barometric pressure effect to the equated partial oxygen pressure.”
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 controlled FiO₂ and direct physiological measurements across two hypoxia types provides strong causal evidence for barometric pressure as an independent variable.
Evidence from Studies
Supporting (1)
Even when the air has the same amount of oxygen, being at high altitude (low pressure) makes your body work harder during exercise than being in a chamber that just lowers oxygen — meaning pressure itself matters, not just how much oxygen is in the air.