That happens often if we lay down and meditate, that we fall asleep, but this is also having benefits for our health by relaxing us.. The book that first got me mediateing was called Mind Calm, and it referred to them as a Meep (meditation and sleep lol).. like its still worth doing even if one falls asleep! Open eye exercises are good like watching the space in a circle for example or letting the eyes wonder around a room whilst simple nameing the shape of the thing you look at..
Many ways ☺ I have tried walking a few times but only for short periods