Gaby
Circadian rhythms — our biological clocks — regulate nearly every process in the human body. U.S. researchers say these rhythms shape physical and mental health and may even slow aging. To get that benefit, we need to reassess daily habits and follow a few simple guidelines so our clocks run more efficiently.
When the Internal Clock Goes Awry
Since the 1990s, scientists have known humans have an internal molecular clock that follows a daily cycle and regulates vital functions like sleep, appetite, and metabolism.
Circadian rhythms operate in nearly every cell and tissue. The master clock — the suprachiasmatic nucleus in the hypothalamus — sits in the brain.
The bad news is that as we age, our circadian rhythms drift out of sync. A recent Northwestern University study compares this to living in a house full of old clocks chiming at different times: the systems that regulate body and brain functions stop operating together the way they did when we were younger.
Researchers link this desynchronization to serious health problems, including cardiovascular disease, obesity, type 2 diabetes, and cancer.
Disrupted Circadian Rhythms Impair Brain Function
Research from Cleveland State University found that a malfunctioning biological clock affects more than sleep and appetite. The team showed circadian rhythms control the body’s DNA repair systems and autophagy — the process that clears damaged cells from the brain. When aging throws these rhythms off, cognitive function declines.
Researchers found circadian rhythms are ‘significantly disrupted’ in people with Alzheimer’s and Parkinson’s diseases. In experiments on rodents with dementia-like symptoms, scientists reset the animals’ clocks by putting them on a consistent daily schedule. The animals’ cognition improved and they lived longer, according to the Daily Mail.
Meal Timing Synchronizes Circadian Rhythms
Dr. Itun Huan, the lead author of the Northwestern study, emphasized that meal timing affects our biological clocks. Eating at odd hours — especially at night — can be harmful. Nighttime meals send unexpected signals when the brain is preparing to rest and can throw rhythms off balance.
The researcher says breakfast helps trigger metabolism and align circadian rhythms at the start of the day.
Other studies show that food timing and calorie reduction can help synchronize internal clocks, particularly when daily intake is cut by about one-third. Some experts recommend reducing calories from roughly 2,000 to 1,400 per day for women and from 2,500 to 1,750 per day for men.
Fruit fly studies found reducing daily food to about 70 percent of normal extended lifespan by roughly 40 percent. Researchers attribute this effect to calorie restriction improving biological-clock function.
Our Habits Need to Adapt as We Age
Researchers also highlighted a problem common in older adults: circadian rhythms become less sensitive to changes in daylight.
As we get older, the eye’s lens loses clarity and the number of light-sensitive cells in the retina decreases. That makes us less responsive to shifts in light levels.
Experts recommend getting morning natural light outdoors to help reset the internal clock.
Researchers have also linked poor sleep in older adults to failing internal clocks. There’s little point in longing for the deep sleep of our 20s and 30s. Accept the changes and adapt daily habits to match your current age.
