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Epidemiological data has shown that working shifts is bad for your health. Shift workers are more prone to diabetes, obesity and hypertension when compared to their counterparts who work during regular morning hours. Even shocking is that in some animal models repeated changes in the sleep wake cycle resulted in premature death. To find out the mechanism behind the increased risk for cadiometabolic diseases in shift workers, 10 human volunteers were subjected to live a 28 hour day (instead of the 24 hour day) for 10 days and various parameters were regularly monitored.

Major Findings

1. There was an increase in the blood glucose level despite an increase in the insulin levels, signifying insulin resistance. More importantly, 3 of the 10 participants with normal glucose levels before study reached pre-diabetic stage during the study. 
2. There was a systematic decrease in leptin. Decrease in leptin can increase the appetite and conserve energy in the body which leads to obesity over a long period of time.
3. There was a 3 mmHg increase in the mean arterial pressure in the study participants in the ten day period. This effect may possibly be responsible for the increased incidence of hypertension in shift workers.
4. The sleep efficiency was decreased, which is an independent risk factor for depression, increased stress, obesity, hypertension and heart disease.

Implications
The results are significant as even a 10 day changes in the sleep wake cycle produces marked alteration in the metabolic functions and hence individuals chronically exposed to such changes are more prone for cardiometabolic disease including diabetes, hypertension and obesity. Shift workers should be aware of their increased risk for obesity, hypertension and diabetes and should undergo regular medical evaluations. They should follow healthy lifestyle practices including regular exercise, healthy diet, cessation of smoking, reduction of weight etc.

Reference: Proceedings of the National Academy of Sciences (PNAS)
For more information visit http://www.pnas.org