Tired as he was, he went to bed early.
Since he was tired, he went to bed early.
He was tired, so he went to bed early.
Being tired, he went to bed earlier than usual.
In the meantime he went to sleep.
In the meantime, he went to sleep.
As soon as he went to bed, he fell fast asleep, for he was very tired.
He went to bed early, as was his wont.
He pointed out the importance of sleep.
Tired from the hard work, he went to bed earlier than usual.
He tried to make up for his lack of sleep by taking a nap.
He went to bed, but he couldn't get to sleep and turned from side to side [tossed and turned].
He was sleeping looking very cozy.
I was tired so I went to bed.