From William Reville, here is a speculation:
Finally, here is a “guaranteed” way to lengthen your life. Childhood holidays seem to last forever, but as you grow older time seems to accelerate. “Time” is related to how much information you are taking in – information stretches time. A child’s day from 9am to 3.30pm is like a 20-hour day for an adult. Children experience many new things every day and time passes slowly, but as people get older they have fewer new experiences and time is less stretched by information. So, you can “lengthen” your life by minimising routine and making sure your life is full of new active experiences – travel to new places, take on new interests, and spend more time living in the preset.
Like some kinds of sharks that need to keep moving to live, I’ve always felt that we need to keep learning to survive. That’s also why boredom is one of the worst feelings in the world — it’s the cerebral equivalent of being buried alive.