According to a recent study, people "hanging" on the Internet or sending messages within 2 hours before bedtime, stress levels in the body more than those, who otherwise spends his evening.
Interestingly, sending emails and watching TV do not have such a negative impact as physical exercise and reading. In any case, such a connection is not established.
Earlier the same researchers found that "walking" on the Internet, e-mails and messages will increase the risk of insomnia. They say that sleep disturbances can be caused by the light that emanates from the computer screen and phone. It inhibits the production of the "sleep hormone" melatonin.
Moreover, the same SMS on the phone, and e-mail make a person concentrate, and if it happens before bed, then it's harder for him to relax and fall asleep.