As KathrynP says above if your quality of sleep at night is not good you may nod off in the day. Hopefully not when you are driving.
My husband popped home one lunchtime and as it was a beautiful day opened the patio doors wide. He sat down to make some phonecalls whilst waiting for a timed delivery. Next thing he knew he was being shaken by a huge tattooed man of about 20 stones. 😱
Turned out he was the delivery driver who had been ringing both door bells to no avail then came round to the side garden and saw my husband slumped in the chair. He called to him, banged on the open glass doors and as he got no response came in as he thought he had died. He very nearly had a heart attack when he found this big bloke in our lounge shaking him!🤣🤣
He falls asleep on planes, trains, ferries, buses, cinemas, even on a rowing machine at a gym.