Brain waves above 12 Hz in frequency; associated with normal waking consciousness. These waves are considered to be “fast” and usually begin in the left hemisphere of your brain. beta waves are present when you get stressed, use our logical thinking skills and when your body tenses up. The most alert or anxious you tend to be, the more beta waves you produce (this is considered a healthy form of wave for typical adults).
People who produce a lot of betas are extremely social, can think on the fly, get excited, are drive to achieve their goals (and tend to perform at their best levels when trying to reach them), can focus easily, are positive thinkers and in general, have more energy (they also have a higher IQ).
This site talks about the dangers of too many beta waves and if you don’t have enough of them, how to produce more: http://4mind4life.com/blog/2008/02/09/beta-brain-waves/