According to the book “You: The Owner’s Manual, by Michael Roizen, M.D. If you want to know how your brain is working? This is what you need to do, close your eyes and lift one foot off the ground. The longer you can stand on one leg without falling, the better your brain is functioning. (Twenty-eight seconds is good for men ages 20 to 30; 23 seconds for ages 31 to 40; 15 seconds for ages 41 to 60).
