Every form of life has a ‘body clock’ that allows synchronisation of various bodily functions, such as sleeping and eating, to the 24-hour light-dark cycle of the day.
In mammals, the clock, or suprachiasmatic nucleus (SCN), is located deep in the brain in the hypothalamus and is directly connected to the optic nerve. It regulates the circadian rhythms by expressing different proteins and hormones.
As organisms age, the circadian rhythms of the body clock often become less synchronised which can result in poor sleep patterns, weakened immune function and general cognitive decline.
Researchers at the University of Glasgow were able to see how important circadian rhythms are by ‘resetting’ the internal body clock of mice through advancing their light/dark cycle by eight hours.
They then observed how long it took for the mice’s body clocks to synchronise again. They found that young mice were able to quickly adapt to the new schedule whereas older mice struggled more.
However, when the older mice were given access to a running wheel, they showed stronger activity in the SCN and synchronised more quickly compared to those older mice without a wheel. The research is published in the journal Age.
Professor Stephany Biello of the Institute of Neuroscience & Psychology, said: “Ageing can impact the daily circadian rhythms leading to impaired sleep and activity cycles.
“Older adults show reduced amplitude of rhythms, manifested most obviously as disrupted sleep. In addition, ageing of the internal clock affects mood and memory.
“Rodents also show significant changes in circadian function with age making them a good model to study the mechanism of age-related changes.
“Synchronisation is key to a healthy immune function, metabolism and mood. Evidence suggests that animals that are more strongly synchronised live healthier and longer lives.
“Our study demonstrates that voluntary exercise has an impact on circadian rhythms and this has implications for the health of older people living with environmentally-induced circadian disruption. It is also indicates another health benefit to regular exercise.”