Whenever I feel overwhelmed by work or study commitments, my go-to way to decompress is going for an evening bike ride along the canal path near my flat. It is something I try to do two or three times a week, usually just as the sun is setting, so the air is noticeably cooler and the route is relatively quiet.
I actually picked up this habit a couple of years ago during a particularly intense exam period. I found myself sitting at my desk for hours on end, feeling completely burnt out and unable to concentrate. A friend suggested getting an old secondhand bicycle just to get some fresh air, and from the very first ride, I was hooked. It quickly turned into a vital part of my weekly routine.
What makes it so effective for mental strain is really the rhythm of it. When you are cycling, you have to stay somewhat alert to steer and navigate the path, which forces your brain to shift away from whatever worries have built up during the day. It provides a proper mental reset. Besides that, being outdoors near the water, away from screen glare and notification pings, creates a sense of calm that sitting on the sofa just does not offer. By the time I pedal back home, I feel physically tired in a pleasant way, but my head feels completely clear.