Why does shift work cause sleep problems? Your body is designed to sleep at night and be awake during the day. But people who do shift work often have to try to sleep when there is light outside. These changes in your normal sleeping patterns can make it hard to fall asleep, stay asleep throughout the night, or wake up feeling refreshed. You may find it hardest to adjust when your schedule first changes or if you return to a typical daytime schedule after working a non-traditional shift, such as nights or evenings. Even if you’ve been working non-traditional hours for years, these disruptions can affect your health.