According to Traditional Chinese Medicine ("TCM") the time you wake in the middle of the night may be due to an blocked or imbalanced in an organ system. Called the Chinese Organ Clock, it specifies a two hour time period for each organ system. According to WellGood the Clock show the window of "time when that particular organ and its related meridians are said to be most energized and working hardest, affecting everything from your emotions to your productivity."
The clock can be used to plan your day so that you maintain your well being and are the most productive you can be. The WellGood article goes on to state that "TCM practitioners believe that your daily dips and spikes in vitality can give you valuable information into your hidden health imbalances."
The two hour period indicated on the clock is when the organ system is at it's strongest and most productive. The two hour period opposite each organ’s time slot is when it is at its weakest, energetically. Take a look at this chart from the Wellness Principle.
More simply the time slots are as follows:
1 a.m. to 3 a.m. is liver
3 a.m. to 5 a.m. is lung
5 a.m. to 7 a.m. is large intestine
7 a.m. to 9 a.m. is stomach
9 a.m. to 11 a.m. is spleen
11 a.m. to 1 a.m. is heart
1 p.m. to 3 p.m. is small intestine
3 p.m. to 5 p.m. is urinary bladder
5 p.m. to 7 p.m. is kidney
7 p.m. to 9 p.m. is pericardium
9 p.m. to 11 p.m. is triple burner time (associated with the thyroid and adrenals)
11 p.m. to 1 a.m. is gall bladder
Waking up in the middle of the night could be a clue as to an issue or issues that need to be rectified. The most common time period for people to to inexplicably wake is from 1 to 3 am. This two hour window is the time of the Liver system. The Liver is hard at work removing toxins from your system. Toxins can be substances, such as alcohol or drugs, or the effects of a less than perfect diet, or high levels of stress or even pent up emotions, specifically holding onto anger, frustration and/or rage. If this process doesn't work properly it may cause you to wake.
Keeping a daily diary of physical and psychological issues, along with the times you become aware of them, and comparing these reflections to the TCM Organ Clock, can go along way to resolving many of the issues in your life.