This works for me.
I enjoy the sun, I read, I think, I absorb, I take notes ... and fall asleep.
When I drift into consciousness I will think myself into a topic, recall an anagram or mnemonic I have made up, then pick up my notes and press on.
Does it work? It can.
You have to make and take the time.
Recoverable memories don't sit for long on the surface of the brain, they need to be embedded. Myelination needs to take place.
P.S. You also have to hope the dog doesn't get bored or get into a fight.