Whether you are a busy person or not, you can still increase your brain power. There are simple activities, believe it or not, that could help your brain to maintain its performance, or even improving it.
People in this modern world usually didn't have the time or simply didn't care about increasing their brain power. And most people still believes that IQ is static and can't change. However, your general intelligence, which is measured by IQ, is dynamic and changing in between some range.
No, I can't guarantee that by doing these things you will improve your IQ to 180. What I know for sure is that you can improve a few points by doing all these simple things. All you need is to be consistent and do it every day.