New Study Links Chronic Jet Lag To Weight Gain, Early Breast Cancer Onset

Anyone who’s flown across the country knows jet lag can be unpleasant. But a growing body of research suggests that subjecting yourself to jet lag on a regular basis can also have major consequences for your health: weight gain, impaired memory — and, according to one new study, even a higher risk for cancer.

To produce this last finding, a team of researchers from the Netherlands raised female mice that were genetically predisposed to breast cancer in an environment that simulated chronic jet lag, in which the timing of light and dark, and warm and cool, were swapped once a week.

“Imagine that you were flying from Amsterdam to Australia one week, and then flying back the next week, for your entire life,” said Harry van Steeg, a researcher at National Institute of Public Health in the Netherlands, and one of the authors of the study. “That’s actually more or less the exposure we did.”

They found that the mice living in this time-shifted environment developed breast cancer far more quickly than those in a control group, who were raised in a normal environment. The time-shifted mice developed tumors in an average of 42 weeks, while the control mice developed them in an average of 50 weeks. The jet-lagged mice also gained significantly more weight than the control group, even though they didn’t eat any more food.

Though the mechanisms behind these adverse health effects still aren’t fully understood, Erasmus University professor Bert van der Hoorst, another co-author on the paper, said the most likely explanation was that they stemmed from problems in the mice’s circadian system, the “internal clock” that can be found in virtually every organism on earth and that control bodily functions as crucial as breathing, digestion and sleep.

The circadian system in mammals is made up of two basic —> Read More