I always have a hard time switching to Daylight Savings time. Even though it is only 1 hour difference, I still have a hard time adjusting. While the light dark rhythm is the central master clock in our brain, every tissue and organ contain peripheral clocks outside of the brain that are synchronized through the master clock. Peripheral clocks coordinate the function of every organ. These clocks regulate hormones, metabolism and more. ¹ To have energy, deep sleep, balanced hormones and to decrease the risk of illness, keep your clocks in sync.

If you are struggling to sleep, lose weight, have energy dips, hormone imbalances and have or at risk of developing diabetes, heart disease, or cancer, your peripheral clocks might not be in sync. 

Metabolic tissues, such as the liver, skeletal muscle, brown fat, and white fat have receptors on the nucleus of the cell that are influenced by the peripheral clock rhythm. The peripheral circadian clocks and energy metabolism are coupled, and they must be coordinated for overall health.²

These intrinsic rhythms are sensitive to external cues, such as changes in light, temperature, and eating. Light directly entrains the master clock, the suprachiasmatic nucleus (SCN) which lies in the hypothalamus of the brain and is responsible for synchronizing internal rhythms.³ Overall health is influenced by the synchronization of the master clock with the peripheral clocks. Just like a car wash, they must work in the right sequence in order to sparkle and shine!

These clocks not only regulate sleep and wakefulness, they also regulate our hormones as well as our body’s sensitivity to these hormones. Cortisol wakes us up in the morning and light shuts down melatonin production.  Melatonin is released when it is dark and cool at night enabling sleep. Insulin and cortisol are affected by light/dark and feed/fast rhythms. These are the most well-known hormones affected by circadian rhythms.

Rhythmic Hormones 

However, there are many more hormones that peak at night and fluctuate throughout the day and are subject to a circadian rhythm.⁴

• Growth hormone is released in small amounts during the day; however, it peaks at night. This hormone is responsible for blood sugar regulation and has some anti-aging and longevity effects. It reduces body fat, can repair DNA damage, reduces triglycerides in the liver (fatty liver), it promotes the regeneration and survival of nerve and brain tissue and preserves cognitive function. ⁴ Growth hormone improved symptoms of hardening of the arteries, enhanced bone density and bone remodeling, and reduced the risk of fracture. Studies show that growth hormone leads to increased muscle strength, fat metabolism, bone density, and skin thickness. It also led to more energy, emotional stability, and sexual function in middle-aged and elderly people. ⁵ Sleep is important for regeneration and repair and release of this hormone which is governed by the master clock and its own peripheral clock.
• Thyroid hormone is responsible for metabolism, energy, temperature regulation, fertility, growth and development and mental function. Thyroid Stimulating Hormone (TSH) also has a clock rhythm. In people with hyperthyroidism (too much thyroid hormone) or hypothyroidism (too little thyroid hormone, the TSH or releasing hormone that regulates production of thyroid hormone is often disrupted. Shift work, travel across time zones or irregular sleep-wake cycles might be a risk factor for disturbances in thyroid hormone secretion and may increase the susceptibility of high or low thyroid hormone and even thyroid cancer. 
• Leptin acts as a strong appetite inhibitor. However, in obese people Leptin signaling is generally disrupted and leads to leptin resistance. Jet lag and eating at night also leads to leptin resistance and leptin resistance from circadian clock disruption may be the link to obesity. ⁶

How to Sync Your Clocks

• Go to bed and wake up at the same time.
• Get light and movement in the daytime.
• Dim the lights at night and sleep in a cool dark room.
• Stop eating at least 3 hours before bedtime.
• Block blue light at night with software programs on tablets, phones or computers (twilight for Android and Night Shift for Apple) or wear blue/green light blocking glasses.
• Do not do vigorous exercise before bedtime, instead to some gentle stretching, yoga or tai chi.
• Give you mind a mental break by choosing relaxing, less stimulating endeavors at night and avoid gripping, disturbing movies or reading. 

Sleep is key to synchronizing your central and peripheral clocks as well as balancing hormones and slowing the aging process and the development of chronic conditions. Get some deep restful sleep and reach out if you need help.

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