Your house

Start making it dark in your house or apartment earlier in the evening than you normally do.
Avoid a quick spell in the gym doing five hundred press ups, or a couple of hours playing the latest 'Axe-Murdering-Car-Jacker III' computer game just before your bed-time.

· Think about how our ancestors got ready to go to sleep - they finished their working day, they had some grub and maybe did a little gentle frolicking in the hay, it got dark, and then they went to sleep.

· These patterns are built into our DNA. If you divert from them you will not be following or satisfying your body's natural urges. Think about your lifestyle, especially what you do as bed-time approaches.