The Over Sleeping.

To sleep beyond the time for waking, usually sleeping time is 8-9 hours at night in excess of it is over sleeping.

Sometimes over sleeping is not good to our body, it loose our energy, the result is indisposed, it make us to sleep more and stay at the bed, that’s fine if we have no work, but if we have, we forget it because of lack of energy. Oversleeping are also a signed of medical problems, such as, diabetes, heart disease, and increased risk of death. it also has a link to two factors like depression and low socioeconomic status, people who of lower socioeconomic status may have less access to health care and therefore more undiagnosed illnesses, that may cause oversleeping.

How much do we have to sleep?

Its varies significantly over the course of your lifetime. It depends on your age, level of activity, your general health and lifestyle habits. Like for example if you are stress or you have an illness, you may feel you need for sleep. But experts recommend that adults should sleep between seven and nine hours each night.

Other reason why People Sleep Too Much.

Not getting enough sleep sometimes by choice like Working at night and sleeping long sleeping during the day taking drug, alcohol, or cigarette use, lack of physical activity and the use of certain medications.

Hypersomnia, this is the people who suffer from extreme sleepiness throughout the day, even they nap it did not relieve their sleepiness, people also with hypersonic experience anxiety, low energy, and memory problems that resulted to almost constant need for sleep.
Obstructive sleep apnea, a disorder that causes people to stop breathing momentarily during sleep, it lead them increased their need for sleep. Because of disruption of their normal sleep cycle.

Restless legs syndrome (RLS) is a disorder is an unpleasant sensation in the legs and a strong urge to move them it gets worse while you’re at rest or sleeping that can greatly interrupt your sleep and lead to sleepiness.

What the effect of over sleeping?

• Sleeping too long or not enough each night can increase the risk for diabetes.
• Sleeping too much or too little can make you over weigh or obsess, if you are sleeping nine or 10 hours every night you were 21% more likely to become obese over a six-year period than were people who slept between seven and eight hours.
• Sleeping longer than usual on a weekend or vacation can cause head pain or headache this is due to the effect oversleeping has on certain neurotransmitters in the brain, including serotonin.
• Lying on the bed all day will give you back pain.

 How to stop or treat over sleeping?

• If you have certain medical problems follow your doctor advices.
• Reset your time frame of sleeping. Change your sleeping pattern by simply going to bed at the same time every night and getting up at the same time every morning.
  Your body will naturally and habitually wake up at this time.
• Don't worry about any lack of sleep from the night before. Always focus on the night ahead
• Tell yourself to wake up on time. So that this decision enters your subconscious mind and becomes a choice to get up on time. 
• Find a reason to get up on time every day a morning routine like For example, you might like to read for half an hour or write in your journal. Or perhaps this is a great time for a jog, walk with the dog or an exercise routine.
• Reduce your level of hours spent sleeping gradually.
• Don't overwork yourself. Take short breaks when necessary, organize your workload, and go outside for fresh air if you start to feel tired.
• Take a nap if possible during the day, it helps you to refresh and energize your body for working in the afternoon.
• Exercise, it helps to regulate sleep cycles as well, and it boosts your mood and lifts your energy, more reasons to help you to seek less sleep.
• Don't exercise too close to bedtime. This can cause you to not fall asleep as you're over-energized, thereby risking sleeping in when you do finally fall asleep.
• Take a cold shower. This will help you to wake up more easily.

Try this method see if you stop your over sleeping if not you have more serious problem,  maybe medical problem like obesity you must go to your doctor for professional advice.

Reference:
http://www.wikihow.com/Stop-Oversleeping
http://www.webmd.com/sleep-disorders/guide/physical-side-effects-oversleeping