What if you woke up and looked at your phone and saw a text you don’t even remember sending? Well phenomena such as “sleep-texting” and “sleep-emailing” are happening right along with sleepwalking.
According to professors at the New York University, our phones have become so integrated in our lives that it’s crossing the boundary between being asleep and being awake.
The kind of messages being sent varies by the sleep-texter; some people send incoherent or just badly spelled messages, and others text as fluently as when they’re awake. A likely factor of this is stress and exhaustion.
I got this information from here and here