HCR Update from Mark Sanna: Circadian rhythms enforce a 24-hour cycle on our bodies and are often mentioned in conjunction with jet lag. In our modern lives, there are many people whose circadian rhythms are disrupted on a regular basis. Shift workers, for example - including nurses, doctors, firefighters and policemen - have regularly disrupted patterns. Other people have 'social jet lag,' a lifestyle pattern that leads them to maintain a normal schedule on weekdays, but then stay up late and sleep in on the weekends. Researchers from the Rush University Medical Center in Chicago have found that when these rhythms are disrupted and combined with a high-fat, high-sugar diet, they could contribute to inflammatory bowel disease and other conditions.