Happy people just don't shoot their husbands, they just don't.

Exercise gives you endorphins. Endorphins make you happy. Happy people just don't shoot their husbands, they just don't. Legally Blonde (2001)

OK, I think this is the best quote ever! I have noticed in my own life the more I exercise the more patient I am with my family. I want to play with my kids more. I want to push play on that exercise DVD. I want to go to the gym. I want to choose healthy things to eat. So, just get up of the couch, and go for a walk. You will be so glad you did!

What are Endorphins?

Exercise decreases the stress hormones such as cortisol and increases endorphins.  Endorphins are the body’s natural feel good chemicals, and when they are released through exercise, your mood is boosted naturally.  As well endorphins, exercise also releases adrenaline, serotonin, and dopamine.  These chemicals work together to make you feel good. 
Endorphins are defined as hormone-like substances that are produced in the brain and function as the body’s natural painkillers.  During exercise, these endorphins are released, and this can produce feelings of euphoria and a general state of wellbeing.  The endorphins produced can be so powerful that they actually mask pain.  Physically active people recover from mild depression more quickly and physical activity is strongly correlated with good mental health as people age.

Types of Exercise to Release Endorphins

The best type of exercise for improving your mood is cardiovascular exercises and aerobics.  This is because vigorous exercise helps to release the chemicals necessary for the mood-raising high.  Yoga is also great as it reduces tension and stress while improving the mood.  It focuses on stretching, breathing, and motion that release negative emotions in the body.

How long do you need to Exercise to Feel the Benefit?

Even if you only exercise for a short period of time, your mood will be improved.  Just ten minutes of moderate exercise is enough to improve your mood, your vigour and also decrease fatigue.  However, to obtain all the benefits from exercise, not just the mood improving aspects, you should do at least 30 minutes of moderate exercise every day.
So next time you are angry at your best friend or cranky because you didn’t sleep enough, get moving. It doesn’t have to take long for the endorphins to take effect; just push yourself and you will feel the benefits.  Try it; your body will thank you later.

Information from:

http://www.naturaltherapypages.com.au/article/Exercise_Endorphins