Stressed and need an idea

Does anyone know a good stress reliever i can do at work while working. I work at a grocery store and have had high stress so I don't know what to do normaly when I'm very stressed i go walk on the treadmill at the gym but cant do that at work. My second resort is read&listen to my music but i still cant do that i cook samples of food on sale or new at my store so if that helps explain part of my problem. Any suggestions?