Millions of Americans write about their day-to-day lives, failures, successes, and adventures in journals. Why? What about journal writing is so satisfying?

Researchers around the world have explored the impact of recording feelings and events. Here is just a selection of insights from their research:

1. Journaling restores your immune cells. A researcher from the University of Texas at Austin found that regular journaling strengthens immune cells (T-lymphocytes).

2. Journaling reduces stress. A 2010 study out of the University of Eastern Michigan found that among (stressed) college students, journaling about emotional stressors reduced anxiety significantly.

3. Journaling reduces the impact of traumatic events. People who journal about traumatic events had greater awareness of the positive aspects of their experience, according to a study from the University of Iowa. This higher awareness contributed to emotional healing and post-traumatic stress reduction.

"By writing, you put some structure and organization to those anxious feelings," said researcher James Pennebaker, PhD, of the University of Texas at Austin. "It helps you to get past them."

4. Journaling helps patients with asthma and arthritis. Writing about traumatic events has a physical impact on those suffering from arthritis and asthma. Joshua M. Smyth, Ph.D., associate professor of psychology at North Dakota State University, found that 47% of patients with asthma and rheumatoid arthritis improved after writing about traumatic events. (In the control group, who wrote about everyday topics, only 24% improved.)

5. Journaling improves the mental and physical health of cancer patients. A 2014 study in Journal of Clinical Oncology reports that “cancer patients who engaged in expressive writing just before treatment felt markedly better, mentally and physically, as compared with patients who did not.”

6. Journaling helps you “throw away” negativity. A study published in the journal Psychological Science agreed that writing thoughts down can be an effective way to clear your mind -- but the positive feelings were increased when subjects actually threw that piece of paper away.

7. Journaling release dopamine. According to Alice Flaherty, a neuroscientist at Harvard University and Massachusetts General Hospital, journal writing and blogging might trigger dopamine release, similar to stimulants like music, running and looking at art.

Journal writing, especially about important stressful events in your life, isn’t just an exercise for the literary-minded -- it has proven positive effects on your physical and emotional health. Do you have a journal?