Skip the coffee. Exercise helps working memory just as well.

Do you drink coffee to "wake up" your brain? A first-of-its-kind study has found that just 20 minutes of exercise works just as well coffee to boost working memory. In addition, exercise can help with things like mood and focus just as much as caffeine. Even a brisk walk can help boost working memory and if you’re trying to get off caffeine for good, it might be worth doing some exercise to fight off the effects of withdrawal.

The research was published in Nature Scientific Reports, but you can read a summary here:

https://www.medicalnewstoday.com/articles/exercise-boosts-memory-like-caffeine#The-side-effects-of-caffeine-