Stress affects circadian rhythm, increases metabolic disease risk

By Angela Betsaida B. Laguipo, BSNNov 12 2019

Stress is a normal part of life, but too much of everything isn’t healthy. Every day, people from all walks of life experience stress of various degrees. A new study found that when stress has disrupted the circadian rhythm, the body’s internal clock, it can increase the risk of developing metabolic diseases.

A team of researchers at the University of Lübeck in Germany found that stress joined with a disrupted internal body clock heighten the risk of having metabolic disorders, including type 2 diabetes and Obesity. The study, which was presented at the Society for Endocrinology annual conference in Brighton, highlights the effects of stress on the body and how it can cause various health conditions.

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Stress and disrupted circadian rhythm affect metabolism

The researchers studied mice models in the laboratory wherein they introduced genetic alterations in various parts of the circadian rhythm machinery. They also exposed the mice to social stress, wherein they exposed the male mice to an unknown and dominant male. The male mice had increased stress responses depending on the time they were exposed to the stress.

In series of experiments, the team also found that the stress responses were also dependent on the internal body clock, and body weight and food intake had been negatively affected when stress happens during their inactive phase, which is during the daytime in mouse, and night-time in humans. Therefore, they found that repeated exposure to stress negatively affected metabolism, due to long-lasting effects on stress responses.

The experiments shed light on who shift-work, chronic stress, jet lag, and lack of good sleep can lead to metabolic disorders. Today, many people are faced with metabolic diseases, including obesity. Many people who are working night shifts, or those who are constantly exposed to stress, suffer from disrupted circadian rhythm. They also experience weight gain and altered metabolism.

The circadian rhythm and stress response

The circadian rhythm or body’s internal clock is a natural 24-hour cycle that is important in the regulation of processes tied to hormones, good health, sleep and feeding. When people are exposed to external stress, the body produces a stress hormone called cortisol for the body to adapt energy metabolism to a fight-or-flight situation. The connection of stress response and circadian rhythm is not yet fully understood, not until now.

“We have shown that stress responses depend on the time of day, are affected by the internal body clock and can interact to negatively affect food intake and body weight to predispose to metabolic disorders. These data suggest that body clock rhythm may be an underestimated factor in assessing the impact of chronic stress on general health and well-being,” Prof. Henrik Oster at the University of Lübeck in Germany said in a statement.

The team wants to conduct more experiments to study the molecular targets of the body clock and stress interaction. They aim to identify the various mechanisms that can affect metabolism. Also, they plan to find ways on how they can curb the bad effects of stress and disrupted body clock on the body.

"Further investigation of this system could lead to recommendations for better timing of working hours, stressful meetings and rest that may increase productivity and enhance quality of life, reducing the financial burden of care for work-related stress,” Prof Oster added.

What is metabolic syndrome?

Metabolic syndrome is a cluster of metabolic disorders. When patients have these conditions together, they are at high risk for future cardiovascular diseases, such as heart disease and stroke. These conditions also heighten the risk of developing type 2 diabetes. The conditions include high blood sugar, high blood pressure, and abnormal triglyceride or cholesterol levels.

The American Health Association (AHA) reports that metabolic syndrome is a serious health condition, and it affects about 23 percent of adults in the United States alone. The underlying risk factors of metabolic disease are physical inactivity, being overweight or obese, advancing age, and genetics.