Is the tension of your busy life keeping you from getting the rest you need? Research on stress and your circadian rhythm shows why anxiety leads to sleepless nights.

If you feel that your life is too stressful, you are not alone. The American Psychological Association has warned that people are living with more stress than ever before and suffering extreme physical and emotional harm as a result. Stress does not just put you at risk for long-term disease; it can also interfere with your circadian rhythm and leave you feeling exhausted on a daily basis.

The Physiology of Stress

The feeling of being stressed is familiar to many of us. Your eyes dilate to allow you to become more aware of your surroundings. Your heartbeat rises and becomes stronger, perhaps giving you the sensation of pounding in your temples. Your skin may become flushed and even sweaty. You may feel shaky or dizzy as your blood supply shunts to your muscles. This response is caused by a variety of factors, with the sympathetic nervous system and cortisol playing major roles. When your brain perceives a threat, your hypothalamus secretes corticotropin-releasing hormone, or CRH. In turn, this stimulates your pituitary gland to release adrenocorticotropic hormone (ACTH), which sends a message to your adrenal glands that your body needs more cortisol, the hormone associated with stress responses.

Because mankind arose out on the savannas, this was once a very healthy response. People who are stressed are more able to perceive visual threats and respond quickly. Their muscles are primed to run rapidly away from danger. However, in the modern world this is not always a beneficial response. Our threats are usually more complex, less deadly and less likely to require a fight or flight response. Over time, stress can cause weight gain, cardiovascular stress and a variety of ill effects. Scientists specializing in circadian biology believe that insomnia and circadian rhythm disruption are two of these ill effects.

The Link Between Stress and Your Circadian Rhythm

Like many hormones, cortisol plays a variety of roles in the human body. When we are chronically stressed, it is released in higher amounts throughout the day. The early light of morning cues the release of ACTH and thus the release of cortisol. Cortisol, in turn, causes ACTH production to shut down, along with giving us an energy boost that is much-needed when we are getting ready to start our day. When people are constantly stressed and producing high levels of cortisol throughout the day, this can cause this negative feedback loop to break down. Even when cortisol levels are high, ACTH production continues, creating yet higher cortisol levels throughout the day that can make it difficult to sleep.

However, this is not the only link between stress and your circadian rhythm. Cortisol also affects circadian genes in liver and adrenal cells. Constant triggering of these genes at random times of day in response to stress can make it so your body never knows exactly what time it is. This can lead to circadian dysregulation in which your body does not release hormones at the right times of the day to support a normal sleep-wake cycle.

What Kinds of Stress are Bad for Your Circadian Rhythm?

Psychological stress is not the only kind of stress that releases cortisol. People also release this hormone when they are under physiological stress, such as when they are at high altitudes, exposed to extreme temperatures or chronically ill. Studies in chronobiology have found that even people who go to space experience this stress and the resulting circadian dysregulation. In addition, people who engage in shift work, working odd or changing hours also are under physiological stress and thus release high levels of cortisol. Stress and your circadian rhythm interact similarly regardless of the source of your tension, which means that people who are emotionally on an even keel but under physical stress will suffer the same effects.

Reducing Stress in Your Life

If you are trying to maintain a healthy sleep-wake cycle, reducing stress is a good step. There are several ways you can reduce stress of all kinds including:

• Engaging in yoga or meditation
• Listening to soothing music
• Taking relaxing baths
• Eating foods rich in antioxidants such as fruits and vegetables
• Taking deep, cleansing breaths

Taking steps to reduce your stress will not only make you feel calmer but allow you to sleep easier as well. While modern life is full of stressors, finding ways to tone down its effects will help you sleep and feel better.