Exercise is not only important for your heart, lungs, and muscles, but also for your brain. Research shows that exercise can help keep your mind sharp, promotes feelings of alertness and well-being, and wards off depression and anxiety. Start with 30 minutes of moderate-intensity exercise 5 days a week, such as walking, swimming, cycling, yoga, tai chi or Pilates. In addition, strength-training exercises can give your brain a boost. For an even greater mental boost try incorporating exercises in multiple directions using intricate movement patterns.