Studies of workers' IQ levels show they rise and fall throughout the day depending on a variety of factors and events. Are you operating at your peak? Here are six ways to boost your mental acuity:Don't be a slave to technology: In more than 80 clinical trials, Dr. Glenn Wilson, a psychiatrist at King's College London University, found that workers distracted by phone calls, e-mails and text messages suffer a greater loss of IQ than if they'd smoked marijuana. The IQ of those juggling messages and work fell by an average of 10 points -- equivalent to missing a whole night's sleep and more than double the four-point fall seen after smoking pot. The drop in IQ was even more significant in men.To keep sharp, resist the urge to check messages continually. Instead, schedule blocks of time throughout the day to retrieve and respond to them.Get eight hours of sleep: Lack of sleep also results in reduced productivity and increased errors. A National Sleep Foundation study found that half of all workers in the United States say sleepiness interferes with the amount of work they get done -- and nearly 20 percent say it causes them to make mistakes. Sometimes those mistakes are tragic. Government investigations of human error in the space shuttle Challenger explosion and Exxon Valdez oil spill cited sleep deprivation as a "direct cause" of those accidents."The brain keeps an exact accounting of how much sleep it is owed," says Dr. William C. Dement, a Stanford University sleep expert who says we all need to get one hour of sleep for every two hours we're awake. "If you sleep one hour less each day then you're supposed to, you will acquire 'sleep debt.' ""Everyone should block out eight hours of sleep," Dement adds. "Consider it an appointment that can't be broken."Get high on brain food: Studies from Switzerland, Hawaii and Boston, Massachusetts, support the memory and cognitive benefits of a diet rich in antioxidants (vitamins C, E and beta carotene) and B vitamins.If you have an important morning meeting, Douglas Kalman, director of clinical research at Peak Wellness, suggests eating a high protein breakfast to help raise your serotonin levels, which produces hormones that make you feel alert.If you're feeling sluggish midday, boost your serotonin with a small dose of carbohydrates, such as fruit or an energy bar. Also, drink lots of water. A craving for sugar can be the initial stages of dehydration.Work out: Exercise boosts circulation and bolsters brain-nurturing chemicals that improve your creativity, reaction time and retention. Researchers at Middlesex University found that participants scored higher on a creativity test after engaging in 25 minutes of aerobic exercise. Likewise, a University of Illinois study found that inactive individuals increased their memory and ability to multitask by more than 15 percent after participating in a walking program.Do mental gymnastics: Mental exercise is important, too. Using your brain to learn a new language, master a new hobby or engage in friendly debate stimulates blood flow and strengthens the connections (synapses) between nerve cells in the brain. A Washington University study found that memorization techniques also encourage the brain to work more efficiently and may reduce age-related memory loss.Dr. Robert Goldman, author of "Brain Fitness," suggests reading challenging books, doing puzzles -- even combing your hair and brushing your teeth with your other hand.Or check out some of the "brain gyms," such as Mybraintrainer.com, which has proven so effective that the testing company Kaplan Inc. offers the service to high school and college students preparing for entrance exams.Think positive, loving thoughts: Finally, a decade of research at the W.M. Keck Laboratory for Functional Brain Imaging and Behavior led by neuroscientist Richard Davidson found that choosing specific thoughts and emotions can permanently change the working of the brain. When participants practiced feeling love and compassion, their brains went into action -- connecting and building new circuitry at high speed. Davidson has concluded that emotions play a strong role in mental acuity and that spending just 10 minutes a day focusing on feeling loving and kind can make you smarter -- and happier.