 He's worked with top Hollywood celebrities, professional and Olympic athletes, and he continues to be very involved in some of today's top health concerns. Let's kind of start at the top, Dr. Pincus, and talk a little bit about what are some of the warning signs that you may be deficient in vitamin D? Okay, well, part of it is how you feel. One of the things, Chris, is being tired for no apparent reason. Okay.