Which of the following factors can reduce tolerance to +Gz?

The correct answer is that all of the mentioned factors can reduce tolerance to +Gz.

Tolerance to +Gz, which refers to the ability of the body to withstand positive gravitational forces, is influenced by multiple factors that can compromise physiological function and overall resilience during high-G maneuvers. Fatigue, for instance, can impair cognitive and physical performance, weakening the body's capability to manage the stress experienced during increased G-forces. When a pilot or aviator is fatigued, their reaction times and decision-making processes can be adversely affected, leading to a drop in Gz tolerance.

Tactical dehydration can also significantly impact Gz tolerance. Dehydration results in decreased blood volume and, consequently, lower blood pressure. During +Gz scenarios, blood pooling in the lower extremities is already a concern, and if the body is dehydrated, it has reduced capacity to maintain adequate blood circulation to the brain. This can lead to a rapid onset of G-induced loss of consciousness.

Medical illnesses further complicate the situation. Conditions that affect the cardiovascular system, respiratory function, or even the nervous system can severely restrict the body's ability to respond appropriately under G-loads. For example, heart conditions may reduce the heart's ability to pump blood effectively