Restarting iphone 5s itself

I have been using Iphone 5s for 2 years, now like a about 2 month ago it started restarting itself, i thought it was me doing it but then like 10 days later it even restarted while booting, i have the latest version of ios and tried to restore, but as result i dosent help still 😟. When im playing Geometry dash then Iphone isnt restarting, But then some minutes later after playing Geometry dash it starts again. Some people said it could be because my old battery? If my Iphone keeps restarting, i can't call, make pictures and other stuff 😢. If someone could help i would say thank you. 🙂