About 320,000 people have been treated for sleeping disorders last year, the Health Insurance Review and Assessment said Monday.The figure is a 73 percent jump from 180,000 in 2007, the state insurance-auditory body said.About one-third of the patients were in their 40s and 50s. According to HIRA, the factor behind the spiraling cases of sleep disorders is extreme stress from work. The fact that they suffer from obesity, hypertension and other illnesses stemming from an unbalanced diet and lack of exercise have contributed to the growing number of patients as well, it added.The National Health Insurance Corporation advised people to set a regular time to wake up and refrain from consuming caffeinated drinks and food.“Keeping smartphones and other electronic gadgets away before sleep could help, too,” an NHIC official said.By Bae Ji-sook ( baejisook@heraldcorp.com