3 types of thinking you can do without

Attitude could play a role in your health and longevity.

While you are the master of your own attitude, you also could have a positive effect on other people's attitudes. A Harvard Medical School study found that one person's happiness triggers a chain reaction that benefits not only his friends, but his friends' friends, and his friends' friends' friends. And the effect lasts for up to a year!

Sadness does not spread through social networks as robustly. There are certain negative thoughts that have been shown to adversely affect health, and just by changing your own thoughts, you can have a positive effect on your health.

Here are three thoughts to lose for better health:

1. Worry. Research has shown that excessive worrying can be hazardous to your health. Studies reveal that workplace stress can increase the chances of heart disease and high blood pressure as well as compromise the immune system. A study of almost 700 Israeli workers found that the people with the most job-related stress were almost twice as likely to develop Type 2 diabetes.

2. Nervousness. High anxiety can have an effect on your brain. A study that compared mellow yet outgoing people with high-strung individuals showed that the mellower people were less likely to develop dementia. The five-year study followed more than 500 elderly people and found the risk of dementia was 50 percent lower for the calmer, outgoing extroverts.

3. Hostility. People who tend to be cynical or harbor hostility toward others may have an increased risk of developing heart disease, according to scientists. The stress brought on by these types of thoughts can cause spikes in an immune system protein called C3 that has been linked to numerous diseases. In a study of Vietnam veterans who were healthy at the beginning of the research, the ones with the highest levels of hostility were about 25 percent more likely to develop heart disease and had the highest levels of the C3 protein.

So, as the Bobby McFerrin song says, "Don't worry, be happy," and enjoy a healthier life.