Tick Tock. Off Your Clock?

Circadian rhythms control acute health episodes

10 a.m. heart attacks? It’s no coincidence. Our internal body clocks are governed by circadian rhythms, where over a period of roughly 24 hours, our bodies generate physiological processes to determine periods of sleeping, eating, and much more.

Diurnal mammals experience clear patterns of brain wave activity, hormone production, and cell regeneration based on sunlight and temperature. This activity occurs in the hypothalamus, located just above the cross point of the optical nerves in the brain.

Whether you’re a “lark” or a “night owl,” your circadian rhythms have been genetically set since birth. They may vary slightly over the span of a lifetime, but we cannot change our chronotype. This makes working the night-shift very difficult for larks, and explains the real causes of jet lag. Melatonin, the hormone produced after darkness, causes drowsiness. When sunlight hits our eyelids in the morning, light-induced signals travel through the brain to turn off melatonin production.

Because [shift workers’] work schedules are at odds with powerful sleep-regulating cues like sunlight, they often become uncontrollably drowsy during work, and they may suffer insomnia or other problems when they try to sleep. Shift workers have an increased risk of heart problems, digestive disturbances, and emotional and mental problems, all of which may be related to their sleeping problems. The number and severity of workplace accidents also tend to increase during the night shift. Major industrial accidents attributed partly to errors made by fatigued night-shift workers include the Exxon Valdez oil spill and the Three Mile Island and Chernobyl nuclear power plant accidents. One study also found that medical interns working on the night shift are twice as likely as others to misinterpret hospital test records, which could endanger their patients. It may be possible to reduce shift-related fatigue by using bright lights in the workplace, minimizing shift changes, and taking scheduled naps. -NIH, National Institute of Neurological Disorders and Stroke

People who suffer from sleep disorders attempt to offset their body clocks by light therapy or increasing melatonin in the form of drug therapy, with some temporary success.

The image indicates which acute disease states coincide with time of day. Many health conditions are regulated by these rhythms. For example, lung function is at its optimal level around 4 p.m. Conversely, it is at its weakest around 4 a.m., the time of day when most asthma attacks occur. Heart problems and strokes escalate during the time that our blood pressure is highest, generally between 9 a.m. and 11 a.m. Deaths from all causes generally occur around 6 a.m.

According to the Centers for Disease Control and Prevention, 30% of all adult employed Americans get no more than 6 hours of sleep, when they really need 7-9 hours. Women sleeping 5 hours per night or less are three times more likely to suffer a heart attack.

6 “Good Sleep” Tips to Maintain Your Circadian Rhythms

• Regulate the amount of sleep by setting a bedtime and wake time, allowing for the recommended 7-9 hours. Try to make it the same 7-9 hours each night.
• Follow your mother’s advice and get in at least 2-3 of those hours before midnight.
• Reduce intake of stimulants 4-6 hours before bedtime. That nightcap is likely to cause sleep disturbances, and choose decaf for your after-dinner coffee. Nicotine has a calming effect, but remember that it’s really a stimulant.
• Keep the bedroom dark by installing light-blocking window shades. This allows for continuous production of melatonin during the sleep hours.
• Relax before bedtime with a hot bath, light reading, aromatherapy, or whatever you find calming. Watching TV, having emotional discussions, and even a cluttered bedroom are likely to subconsciously invoke anxiety in that room over time.
• Eat to sleep. Like turkey, milk contains tryptophan, an essential amino acid related to relaxation and restfulness. Other sleep-enhancing foods are shrimp, tuna, halibut, pumpkin, bananas, peaches, apricots, avocados, artichokes, asparagus, almonds and walnuts, oats and eggs.

Ready to get back on the clock now? Sweet dreams.

Related Study: Why the Circadian Rhythms Affect Health