Crying makes a person feel tired for a variety of reasons, the most significant being the powerful emotions and natural release of tension that comes as a result of shedding tears. Scientists believe that crying releases stress hormones and toxins from the body, according to WebMd.
Physical effects of crying include the unpleasant experience of an increased heart rate and sweating as well as the more calming effect of slower breathing, according to ScienceDaily.com. The calming effect tends to linger longer than the unpleasant effects, however, which is why most individuals report feeling better after crying. People with anxiety or mood disorders are less likely to experience the benefits of crying.