Why is Listening to Your Body Clock Important? A HealthCentral Explainer

What is the body clock?

The body clock is our internal genetic mechanism that regulates our functions on a 24-hour cycle—including our sleep patterns and metabolism. Researchers are discovering that disruptions to our circadian clocks can cause health issues, such as insomnia, obesity, metabolic issues, and immune system problems.

In modern society, ignoring our body clock to stay up later, particularly while using devices, such as iPads, smartphones and laptops, are contributing to disruptions to our natural sleep cycles. One study calls this phenomenon “social jet lag,” and not only is it causing people to be chronically sleep-deprived, it also could be contributing to the obesity epidemic.

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How are sleep and the body clock connected?

Our biological clock is set by daylight and nighttime darkness to provide us with the best window for sleeping and waking. As we stay up later, not only is the body clock disrupted, but the people who do this are more likely to smoke and drink more alcohol and caffeine. Researchers who have compiled a database on human sleep behavior have been seeing trends for the past 10 years. Their analysis shows that people who have severe social jet lag are more likely to have higher body mass indices (BMIs).

Interestingly, the relationship between social jet lag and BMI was not connected to duration of sleep, but rather when they slept. This suggests that it is not about the amount of sleep you get, but instead about being out of sync with your body clock.

What about our metabolism?

As with sleep, when you eat may be more important than what you eat. A study, published in Cell Metabolism, looked at two groups of mice on high-fat diets. One group was restricted to eating for eight hours a day, while the other group was allowed to eat around the clock. Researchers found that while both groups ate the same amount of food, the group on the restricted eating plan was less likely to suffer obesity and metabolic issues.

Researchers say this suggests that eating out of sync with our body clocks is partially responsible for poor health. For instance, every organ in our body has a certain amount of time per day at which it works at peak efficiency, according to the lead researcher. The rest of the time it is in a far less active state. The metabolic cycles are important for several processes, such as breaking down cholesterol and producing glucose, which should be “turned on” during meal times and “turned off” when not eating. This cycle can be disrupted when people regularly eat throughout the day and night.

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Is our immune system affected by our body clock?

The immune system is also potentially affected by disruptions in body clock cycles, according to a study published in Immunity. Researchers at Yale University suggest that body clock disruptions could leave our bodies more vulnerable to disease.

The study, using mice, found that the circadian clock controls the activity of an important gene in the immune system, called Toll-like receptor 9 or TLR-9. This gene reacts to the DNA from bacteria and viruses. They found that the mice’s ability to resist infection were greatest when TLR-9 was at its highest level. The same was true for the mice’s immune response to vaccination. The findings suggest that body clock disruptions, such as jet lag could cause illness and that there may be better times to get vaccinated. This could lead to new ways to prevent and treat diseases, with therapies designed to optimize the immune response.


Alice G. Walton. (2012, May 23). “Not Getting Consistent, Adequate Sleep is Still Really Bad For You.” The Atlantic Monthly Group. Retrieved from http://www.theatlantic.com/health/archive/2012/05/not-getting-consistent-adequate-sleep-is-still-really-bad-for-you/257369/

Cell Press. (2012, May 12). "Hazardous To Health - Social Jet Lag." Medical News Today. Retrieved from

Grace Rattue. (2012, May 22). "When You Eat Is As Important As What You Eat." Medical News Today. Retrieved from http://www.medicalnewstoday.com/articles/245709.php.

Catharine Paddock PhD. (2012, February 18). "Disrupted Body Clock Weakens Immunity." Medical News Today. Retrieved from http://www.medicalnewstoday.com/articles/241863.php.

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