The timing of anticipation for a painful stimulus, specifically 2 seconds or 2 minutes before, can worsen the pain experience.

“However, the timing in which that anticipation occurs is vital for this to happen. And if that timing isn't quite right, it actually can make the experience of pain far worse. So here I'm summarizing a large amount of literature, but essentially if subjects are warned that a painful stimulus is coming, their subjective experience of that pain is vastly reduced. However, if they are warned just two seconds before that pain arrives, it does not help. It actually makes it worse. And the reason is they can't do anything mentally to prepare for it in that brief two second window. Similarly, if they are warned about pain that's coming two minutes before a painful stimulus is coming electric shock or a poke or cold stimulus or heat stimulus that's pretty extreme, that also makes it worse because their expectation ramps up the autonomic arousal.”