With long workdays and fully-booked nights, it's no surprise that sometimes a solid eight hours of sleep is just not an option for many. According to the National Sleep Foundation's 2012 "Sleep in America" poll, about one in ten Americans say they are likely to fall asleep at an inappropriate time -- like during a work meeting. With some jobs, falling asleep at inopportune times is simply embarrassing, but in other lines of work, falling asleep is very dangerous. Try these to relieve fatigue and stay productive: Get up and go. Studies from the American Heart Association say that movement increases the flow of blood to the brain, which, in turn, helps you feel more alert. Incorporating more activity into your day can give you a mood boost, too. A study of 210 UK workers, most of them with sedentary jobs, found that exercising during the workday made them feel more forgiving of their coworkers' mistakes and more confident in their own abilities, as well as increased their work performance. Take a short walk outside the office, or inside if the weather isn't cooperating, and take the stairs instead of the elevator. Stand while talking on the telephone, and take regular breaks for stretching. Pack some protein. A 2011 study published in the journal Neuron found that protein stimulates orexin cells in the brain, which send electrical impulses that keep us alert and awake. A carbohydrate-rich snack, on the other hand, boosts blood sugar and then lowers it just as quickly, which can cause that drowsy, dragging feeling. Quick, work-friendly, high-protein bites include a hard-boiled egg, a cup of Greek yogurt, a handful of pumpkin seeds, or almonds. Give in to your caffeine craving. The reliable favorite, caffeine, undoubtedly works to keep your eyes open, but what's the healthiest way to get it into your system, and how much is enough? Experts consider 200 to 300 milligrams of caffeine per day a moderate amount. So to avoid jitters or insomnia later in the day, limit yourself to three eight-ounce cups of coffee. By comparison, according to the Mayo Clinic, black tea can have up to 61 milligrams per eight ounces. Coffee and tea are a better choice than sugary and sodium-filled energy drinks and sodas but should still be sipped in moderation. Let the light in. Does your work environment feel like a cave? With no indicators of time of day or weather conditions, fluorescent lighting, and bleak surroundings, it's easy to feel sleepy. If you don't work in proximity to windows, studies have shown that having a live plant can be just as effective. A study recently conducted at Washington State University showed that having plants around a work area can greatly improve employees' energy level. The results showed that workers with desk plants were 12 percent more productive and less stressed than those who worked in an environment with no plants. Subject reaction time in the presence of plants was also 12 percent faster than those in the absence of plants. Keep tabs on your hydration. Water is important for your overall health and plays a part in energy levels as well. Dehydration can cause fatigue, so be sure to drink plenty of fluids. Also consider eating foods high in water, including strawberries, watermelon, cantaloupe, peaches, cucumbers, tomatoes, and zucchinis, to replenish.