When it comes to health and happiness, either one can be the cause or effect. Research shows that when we feel happy, we're more likely to be healthy and stay healthy [source: University of Kansas]. The improving effect of happiness on health has been found in both industrialized and impoverished regions of the world. While being happy won't cure us of an ailment, it does have preventive qualities that are as important to our health as factors such as smoking, age and exercise [source: Center for the Advancement of Health].
Exercise has a positive effect on our body as well as our mental health. Exercise prompts the pituaritary gland to produce and release endorphins, neurotransmitters that bind themselves to opiate receptors in the brain, diminishing our perception of pain. Additionally, the presence of endorphins prompts our bodies to release additional sex hormones such as norepinephrine into our systems, which enhance our mood and sense of well-being.
The exercise doesn't need to be intense. Walking, for instance, increases your energy and improves your mood. Research shows that the number of steps we take each day directly affects our happiness, self-esteem and even conscientiousness about our health and diet [source: Gloady].
Intriguingly, although mental fatigue doesn't affect the functioning of the heart or muscles, our physical performance and endurance decrease when we begin working out following a period of mental exertion [source: American Physiological Society]. This may partly explain why we're less inclined to exercise when we feel stressed out or depressed, even though our emotional well-being would benefit from it.
And it's not just about exercise -- increased happiness may be just a sound night's sleep away. Poor sleep patterns have long been viewed as a product of poor mental health, but much like the two-way cause-and-effect street that links health and happiness, it seems that poor sleep may also be a strong contributing factor to depression and ADHD. In fact, sleep disorders -- and their effects on mood, cognitive ability, and behavior -- are often mistaken for other mental illnesses [source: Young].
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