People might get hypnic jerks when doing this
However, 
many people have noticed that hypnic jerks might subside by... [DOC] [TLE] Body Jerks, But Awake - Neurology - MedHelp [PAR] My wife has (from what I've researched) hypnic jerks while falling asleep and ... 
She might be reading, walking, writing, talking, or pretty much any activity.