"I eat and travel alone, stop and go everywhere, read and write letters alone and talk to myself." A San's Leaves has aroused the hearts of many introverts. Since even talking and heart-to-heart are competing with each other, everyone can do it himself, let alone exercise and fitness. DIY-at home-a training environment, get some barbells, yoga mats, teaching CDs and so on. No one will rob your equipment or bother you. Practice as much as you want. It's okay to have a nude exercise when you are happy. I think this is the most relaxing and comfortable way to exercise. However, a study by Princeton University in the United States shows that long-term exercise alone produces loneliness, which is not good for your health. The team led by researcher Elizabeth Gould published an article in the journal Nature Neuroscience, saying that studies on mice show that normal running has many benefits, including the birth of new brain cells. However, if the mouse runs alone, it will not be able to produce new brain cells, and running for a long time will increase the stress of the experimental mouse and increase the corticosterone in its body. However, due to the abnormal proliferation of brain cells, the level of corticosterone, an emergency hormone, will also increase in lonely mice under stress, which is not only harmful to their health, but also leads to their physical and psychological "withdrawal symptoms". In other words, loneliness can make normally beneficial activities useless-at least in mice.