Circadian Rhythm’s Impact on Body Weight

circadian rhythm impact on body weight

Circadian Rhythm’s Impact on Body Weight

Circadian Rhythm: We all have an ‘internal clock’ which regulates our body’s functioning by using environmental signals.  If you find yourself naturally more alert at certain times of the day (10am) and more sluggish at other times, you have experienced your own circadian rhythm.  The problem; however, comes when daily tasks throw off this internal clock.  During the summer months, we might be more likely to tamper with our circadian rhythm. This can be by staying up late with friends or to study, increase in travel to other countries or time zones or doing shift work.

Research has shown that disruption to our circadian rhythm can wreck havoc on our natural sleep-wake cycle which is responsible for releasing hormones that impact our immunity, digestive function, mood and energy.  Shift workers are at higher risk for cardiovascular disease (CVD) due to increased incidence of elevated blood pressure, elevated blood sugars, high blood fats and abdominal obesity.  Seeing that approximately 1 in 3 Canadians work shifts and considering that we live in a chronically sleep deprived society, tampering with our circadian rhythm is a significant health concern.

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How does Circadian Rhythm Work?

Our ‘internal clock’ works by coordinating our bodily processes so we can work at peak performance.  Therefore, every morning to help us awaken, the production of sleep hormone (melatonin) stops.  With sunlight, our brain sends signals to our body to increase our body temperature and produce a stress hormone (cortisol) which promotes hunger and alertness.  In the evening we experience our highest levels of the sleep hormone (melatonin) known as the ‘darkness hormone’ since it is secreted during periods of darkness to promote sleepiness.


Why Increased Risk for Weight Gain?    

Those with disruptions to their circadian rhythm are at a greater risk for weight gain due to poor food choices (junk foods), irregularity in eating, generally increased caloric intake, decrease in digestion and decrease in physical activity.  While awake in the evening our body also produces a stress hormone (cortisol). Which increases blood sugar level and increases another hormone (insulin) responsible for lowering blood sugar.  Over time, tampering with our natural circadian rhythm can lead to a higher risk to developing diabetes.

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Bottom Line:

Sleep is vital for weight control. I am sure you have heard about it on the news or read about it in the newspaper; but now you can think about the power of your circadian rhythm role in weight management!   To stay in tune with your internal clock, aim for a regular and consistent bedtime and 7-8 hours of sleep each night.  First thing in the morning, be sure to eat a substantial b-fast when your hunger hormones are the highest. Decrease your caloric intake during the day when our digestive processes slow down.  Also, be sure to turn off electronics, TV and bright lights in the evening so that your sleepy hormone (melatonin) can work its magic.