The meaning of the verb subscribe is to write underneath, to sign. This word is often seen online, where websites and companies invite their audience to subscribe to their channels, newsletters, blogs, etc - in other words, to arrange to receive something. In these cases, subscribing implies writing your email address.
Answer: give them more options for extracurricular activities, let them go out, have them walk to school, etc. it’s not hard to keep our young people healthy :)