Shift-work or chronic jet-lag have profound consequences on circadian and metabolic events in the body. Animals that are forced to eat during their resting period show increased body mass and altered expression of clock and metabolic genes.[medical citation needed] In humans, shift-work that favors irregular eating times is associated with altered insulin sensitivity and higher body mass. Shift-work also leads to increased metabolic risks for cardio-metabolic syndrome, hypertension, inflammation.