clear (someone's) cobwebs

Translations
освежить (чей-то) разум
A brisk walk in the fresh air will clear your cobwebs.
Быстрая прогулка на свежем воздухе освежит ваш разум.
Definitions
To refresh someone's mind or make them feel more alert, often by engaging in a stimulating activity or getting fresh air; it can also mean to help someone overcome confusion or mental sluggishness.