Switching to this mode before bedtime has been suggested as a way to help promote sleep.
Times,Sunday Times
If all that doesn't work, there's a special pillow on hand with inserted speakers that play sounds designed to relax the brainwaves and promote sleep.
The Sun
Has also been known to promote sleep.
The Sun
Evidently his nuits blanches have their creative moments, for he's just launched a €7 million campaign to promote sleep.
Times, Sunday Times
Keeping the bedroom cool can help the body release hormones that promote sleep.
The Sun