Final answer:
Dehydration and slow, gradual acceleration reduce the body's G-force tolerance, while proper training and wearing a G-suit enhance tolerance.
Step-by-step explanation:
The factors that reduce the body's G-force tolerance are dehydration and slow, gradual acceleration. Proper training and conditioning, and wearing a G-suit, are actually factors that can enhance G-force tolerance. Dehydration can impair physiological responses and decrease blood volume, reducing the body's ability to withstand high G-forces. Moreover, while slow, gradual acceleration might seem less intense, it provides a prolonged exposure to G-forces, which can be more taxing on the body compared to a short burst of higher G-force.