Maximal exercise at high altitude does not exacerbate inflammation in the human brain

Area of Science:

• Exercise Physiology
• Neuroinflammation
• High Altitude Physiology

Background:

• The impact of high altitude (HA) on neuroinflammation and how exercise affects this response remain unclear.
• Previous research has yielded equivocal findings regarding neuroinflammation at HA.

Purpose of the Study:

• To investigate whether maximal exercise at HA exacerbates the neuroinflammatory response.
• To determine the effect of acclimatization to HA on brain cytokine exchange during maximal exercise.

Main Methods:

• Healthy adults (n=12) underwent maximal exercise tests at sea level and HA (3800m).
• Trans-cerebral cytokine exchange was assessed using arterial and internal jugular venous blood sampling.
• Blood flow was measured to calculate cytokine uptake/release by the brain at rest and post-maximal exercise.

Main Results:

• Resting cerebral cytokine exchange was similar between sea level and HA.
• Maximal exercise increased systemic leucocytes at both altitudes.
• A net release of interleukin-6, interleukin-8, monocyte chemoattractant protein-1, and macrophage inflammatory protein-1 beta from the brain occurred post-exercise, independent of altitude.

Conclusions:

• Partial acclimatization to 3800m does not alter the physiological release of cytokines from the brain in response to maximal exercise.
• The adaptive physiological response to maximal exercise involves net cytokine release from the brain, irrespective of HA exposure or systemic inflammation.