What are typical signs of G-LOC or high-G intolerance?

• A. Euphoria and increased energy
• B. Graying out or tunnel vision, dizziness, confusion, loss of consciousness
• C. Nausea only
• D. Tingling fingers

Answer: (B)

When the body is subjected to high G-forces, blood tends to pool in the lower body, so the brain receives less oxygenated blood. This produces a recognizable sequence of signs that reflect the brain and retina becoming hypoperfused. The first clear indicator is changes in vision—graying out or tunnel vision—as blood flow to the retina and visual cortex diminishes. As cerebral blood flow drops further, you can see dizziness and confusion as more brain areas become deprived of oxygen. If the exposure continues, consciousness can be lost, resulting in G-LOC.

This pattern—visual impairment progressing to disorientation and then loss of consciousness—is the hallmark of G-LOC or high-G intolerance. The other symptoms aren’t as specific: euphoria and increased energy don’t fit the hypoperfusion picture; nausea can occur but isn’t the defining sequence; tingling fingers aren’t typical indicators of G-LOC.