The primary cause of difficulty staying asleep near morning is insomnia, which is defined as difficulty falling or staying asleep, or sleep that's simply not refreshing. These awakenings may occur throughout the night, but they tend to be more frequent in the second half of the night, due to a diminishing ability to sleep toward the morning hours.
The ability to sleep is linked to two processes, one called the homeostatic sleep drive and the other being the circadian rhythm (which will be discussed more later). The homeostatic sleep drive is the gradual desire for sleep that builds the longer a person stays awake, and relates to the gradual accumulation of a chemical within the brain called adenosine. This "sleepiness signal" eventually helps to initiate sleep; during sleep, it's cleared away so that midway through the night, the desire for sleep is depleted.
Tips for falling back alseep!
1. Preserve the darkness. Keep the room dark when you wake up. Keep a small book light or mini flashlight next to your bed and use it to navigate your way to the bathroom, or put a dim night-light in the bathroom and leave the door cracked, so you can find your way there. Whatever you do, don't turn on the overhead light in the bathroom once you're inside.
2. Move the clock out of reach. Constantly checking the clock and calculating how long you've been awake only feeds your anxiety: "Oh no, now I'm only going to get five hours of sleep." Set the alarm, then move the clock where you can't see or check it.
3. Write it down, then let it go. On your bedside table, keep a notebook and pen devoted solely to nighttime "worry lists." Using a dim night-light, write down each thought that's bothering you. Then, after you write it down, make a conscious effort to cross it off the list in your mind. In the morning, transfer the action items to your to-do list. Over time, you'll develop faith in yourself that writing down your worries equates with getting them done.
4. Breathe and ease. In his book The Worry Solution, anxiety specialist Martin Rossman recommends a three-step approach to sleeplessness that really works. First, do "belly breathing," which means breathing deeply enough that your diaphragm rises and falls. Next, isolate each part of your body, from your feet up to your neck, by tensing and relaxing it. Finally, imagine yourself in a favorite place, such as lying in the sun on the beach. Use all of your senses; imagine that you're hearing the waves and smelling the salt air. If it doesn't work the first time, do all three steps again in the same order.