There’s a theory that being out in nature is good at reducing stress. I’m not sure why anyone had to do a scientific study on this, as anyone who’s been out in nature knows it’s very peaceful and calming.
When you’re doing a PhD it’s hard to take a break. This is especially true if you’re doing it part-time and also working or raising a family (or both!) There are only so many hours in the day, as you’ve all learned. But taking those breaks and actually getting away from it all can be a very good thing.
I still relish the opportunity to get out of the house and go for long walks. So many people underestimate walking as a form of exercise, but it’s easy on your body and also burns a lot of calories, if you keep a good pace and walk far enough. And it also means you can get out in nature. I’ve been very lucky in that everywhere I’ve lived there have been places nearby to go and walk in nature. I enjoyed day hiking while in England, and I’ve started doing so again now that I’m back in Southern Ontario. Most people don’t realize, but we have hundreds of kilometres of public hiking trails in this part of the province. In fact the longest hiking trail in Canada literally crosses the road on which I live.
You may not have a trail so close, but if you have sidewalks or parks then make use of them. Take an hour off and go for a walk. Take a whole day and go for a long walk around the city in which you live. It’s an entirely different way of seeing the world and it’s very relaxing. And if you can get close to trees/grass/flowers/etc then do so, because it will calm your mind and lower your stress levels, and that’s very important while you’re doing a PhD.