/sci/ - Science & Math

What are some safe, well-tested means of boosting brainpower?

There's a lot of bullshit floating around about how to boost IQ, but that's not what I'm interested in. I'm more curious about daily habits that increase the amount of intellectual output a person is capable of. Some questions:

How much caffeine is too much?

What's the best time of day for productivity?

Does exercise really improve mental performance?

Any opinions on sleep cycles, concentration drugs, or mental exercises such as n-back?

Links to studies would be great.