Working out regularly can boost the mood of those with chronic pain and illnesses such as back pain, cancer and heart disease. A study published in the Archives of Internal Medicine analysed 90 previous studies of exercise and mood correlation.

Feeling perky in the mornings, but slightly morose by the end of the day? Researchers at Cornell University in New York monitored the mood rhythms of 2.4 million people in 84 countries using Twitter, a social networking website.