Subspace stress
Subspace stress was a possible effect of traveling at high warp speed. It could affect objects and lifeforms.

In 2372, prior to his warp 10 flight, The Doctor detected an enzymatic imbalance in Tom Paris' cerebellum that had a small chance of causing a brain hemorrhage under subspace stress. ()

Despite the simulation of this warp 10 flight in which the subspace stress did not affect the nacelles, Harry Kim and B'Elanna Torres later learned that the stress was affecting the ship's body not the nacelles. The solution was the creation of a depolarization matrix around the fuselage. ()

When a group from the Trill Science Ministry conducted experiments on the Bajoran wormhole to create an artificial wormhole, the  launched a probe into the wormhole. At first, the subspace field stress was within normal parameters but later went up to 15%. ()

Subspace phenomena