Circadian Rhythms Keep Us On Beat
Every body comes with its very own metronome to help us keep time, called circadian rhythm. Signals are sent from the brain to the body indicating when during a 24-hour period we should be awake, and when we should be asleep. When this beat is disrupted due to things like a change of time zone or working night shifts, so are your natural rhythms. Circadian rhythm has been observed in humans, plants, animals and fungi. But why do we need this internal timekeeper?
The story of circadian rhythms begins in the hypothalamus, which is the control center. This control center considers a number of factors, including when it’s light outside and when it’s dark, local environment, and temperature before establishing circadian rhythms. The goal of the hypothalamus is to set the internal clock to capitalize on environmental resources, or to help us get the light and food we need to thrive.
For people with daytime patterns, the body activates cortisol early, triggering an alert state. These levels dip midday, which is why many early risers crave a post-lunch nap. Once it’s dark outside, cortisol declines and melatonin levels rise, and this chemical adjustment makes the body tired. Night owls, on the other hand, have different circadian rhythms that translate dusk as the time for increased output, and very late at night or dawn as the time to consider rest. Night owls often struggle with standard 9-5 office jobs and conventional school schedules because they profoundly disrupt their circadian rhythms. All varieties of circadian rhythms work best when they’re consistent, with set times for going to bed and waking each day.
So what happens when these rhythms are disrupted? A term many people are familiar with is jet lag, and the fatigue, confusion, and insomnia that come along with it. Jet lag occurs when travel to another time zone disrupts established rhythms. A clock in a different time zone might read 10am, but if your circadian rhythms believe it’s 9pm, you’re in for a difficult day. Thankfully, rhythms can adjust once the brain understands when the day has the fullest light, but for many people this process takes multiple days.
Disruptions are also common with night shift workers naturally inclined towards daytime schedules. A study published by The International Journal of Obesity reveals that eating times directly inform development of metabolic syndrome, and hypertension. High fat intake in the evening had an especially pronounced impact on weight gain. Shift-work that demands irregular eating times also leads to altered insulin sensitivity, higher body mass, and chronic inflammation.
In order to remain healthy, we must develop a consistent relationship with our natural rhythms, whether day people or night people. This means maintaining set times for sleeping, eating, and waking up. Listen to your body’s music and enjoy a better mood, a more active mind, and great physical health.