Sometimes completely forget to do anything. I had 3 breaks in the Cardschat 888 tournament earlier, first one forgot to do anything, next two had a cup of tea.
Sometimes I could be in another tournament that doesn't break at the same time
Make a cup, or pot of coffee and use the restroom. clear my head a moment, may look at how far I am from last or how close I am to first chip wise, then pick my music that I will be listening to after the break.
Look at the tv and start watching a movie then forget about the tournament or if I want to finish the movie I keep calling if I know I'm going to lose just so I don't get bothered from poker
Really depends on the situation, if i'm in the late stages of the tournament I really like to use the time to go through some previous hands to refresh myself on the other players' playstyle.
Take a look at tournament lobby see how many orbits people have. See the texture of the stacks. See how many chips there are in play. Look for juicy tournaments go to bathroom and drink plenty of water.
Usually during the five minute break I like to run to the bathroom, refill my drink or let my dog outside if he needs to go lol. Mostly just whatever needs to be done that can be done in five minutes.
For me, 5 minutes break, it's not much, but I have enough to go to the toilet to smoke and make tea with sandwiches, but sometimes it's not enough for me 5 minutes, it would be better to do 10-15 minutes break in tournaments!
Get up, walk around to get the blood flowing again, get something to drink, if i have time to spare i literally move my body and jump up and down because 55min sitting is a long time.