Cognitive Function is Unaffected during Acute Hypoxic Exposure but was Improved Following Exercise

Area of Science:

• Cognitive Neuroscience
• Exercise Physiology
• Environmental Physiology

Background:

• Cognitive function is crucial for military performance, especially under stress.
• Hypoxia, a state of reduced oxygen, can impact cognitive abilities.
• The Stroop color-word test assesses executive functions like attention and inhibition.

Purpose of the Study:

• To determine if acute hypoxic exposure affects cognitive performance using the Stroop test.
• To evaluate the impact of a demanding exercise battery on cognitive function under normoxia and hypoxia.
• To compare cognitive performance changes between normoxic and hypoxic conditions post-exercise.

Main Methods:

• 14 active participants completed the Army Combat Fitness Test (ACFT) events under normoxia and two levels of normobaric hypoxia (FiO2 16% and 14.3%).
• The Stroop color-word test was administered pre- and post-exercise to assess cognitive performance.
• Peripheral oxygen saturation (SpO2) and heart rate were monitored throughout the protocol.

Main Results:

• Stroop test performance (score and response time) was not significantly affected by acute hypoxic exposure (FiO2 16% or 14.3%).
• Participants demonstrated improved Stroop test scores and faster response times after completing the exercise battery.
• Peripheral oxygen saturation (SpO2) was significantly lower during hypoxic conditions compared to normoxia.

Conclusions:

• Acute hypoxic conditions at FiO2 16% and 14.3% do not impair cognitive performance on the Stroop color-word test.
• Physical exertion, regardless of oxygen availability, enhances cognitive function as measured by the Stroop test.
• The Stroop test may be a robust measure of cognitive function in environments with moderate hypoxia and physical stress.