Take a quick walk
Take a few brisk laps in the office hallway or even go outside. This will not only rev up your body, but also your brain--so you can go back to your work more focused and refreshed.
Did you know that dehydration can make you tired? Fill up your water bottle in the morning and keep sipping throughout the day. Drinking water has another benefit: It can help curb your hunger.
Eat a balanced lunch
Choose foods that are low in fat and sugar so your blood sugar levels don't spike--and then crash in a few hours. While you shouldn't overeat, do include a complex carbohydrate, such as brown rice, whole wheat bread or crackers. This will help you feel full and fuel your brain.
Eat a healthy snack
Snacking is fine in small amounts since it helps you to stay alert, provided you stay away from the candy machine. The best healthy snacks include almonds, string cheese or fresh fruit.
Stand up and stretch
Just standing up and stretching at your desk for a minute or two can help revive you. Be sure to breathe in and out deeply so you send oxygen to your brain.
Talk to someone
Getting up and interacting with co-workers can refresh you by engaging both your body and mind.
Have a cup of coffee or tea
Caffeine is a proven and time-honored way to invigorate your brain, and the antioxidants in tea are an added health bonus. Just don't drink so much you get the shakes.