I agree. The study seems keen to point out that there are various cycles of the brain with various lengths. They claim to have identified a 2-week cycle. It see

I agree. The study seems keen to point out that there are various cycles of the brain with various lengths. They claim to have identified a 2-week cycle. It seems likely the brain has all kinds of cycles at geometric-sequence varying frequencies. A ~100hz cycle for updating your vision. A ~20khz cycle for detecting sound pressure changes. A 90 minute sleep cycle. And now apparently, a weeklong cycle and a 15-day cycle. A bad sleep on Sunday night might dampen my whole week if I don't get a chance to make up. A paycheck only comes once every 2 weeks. My brain is a bit different a few days before receiving a check than a few days after. The rest of the article seems to be advice about "maintain healthy habits so they stick" which is nothing new.