Exercise maintains 'rhythm of life'

Exercising at a regular time of day may help to ward off mental health conditions by protecting the body’s natural circadian rhythms, research suggests.

In tests with mice, a team of scientists in Liverpool, Manchester, Exeter and Bristol have shown how scheduled exercise can alter animal behaviour as well as electrical, chemical and genetic activity in the brain to stabilise abnormal body clock function.

The research, published today (18 June, 2021) in the journal Communications Biology, raises the likelihood that physical exercise may be useful in the treatment of conditions associated with weakened biological timekeeping, such as bipolar disorder and a plethora of negative health indications related to shift-work.

Dr Alun Hughes, a senior lecturer in vertebrate physiology at Liverpool John Moores University, said: “Mammals have evolved internal body clocks that organise the timing of their physiology and behaviour. Disruption to the function of these clocks is detrimental to health and is a common factor in human ageing and a wide variety of illnesses, including mental health disorders. 

Preserve health

“Exercise may well be one way to counter these imbalances and preserve health and wellbeing.”

The activity of these internal body clocks can be altered by a range of factors, including light, food and physical activity. In this project, we sought to answer the question ‘Can regular exercise fix a broken body clock?’.”

Dr Hughes and colleagues used a range of transgenic mouse models that exhibit disrupted daily body clock function and recapitulate some features of ageing. 

These mice, along with ‘normal’ mice as controls, were allowed scheduled exercise in a running wheel at the same time every day for some weeks, and their body clock function was assessed. 

Enhanced brain signals

They found that scheduled exercise restored daily body clock function, leading to improvements in brain activity as well as daily rhythms in gene expression and behaviour. 

The researchers further assessed the activity of GABA, the main inhibitory chemical in the brain, and found that regular exercise increased GABA signalling in ‘normal’ mice, but reduced it in the transgenic animals. 

“Our observations around this neurotransmitter raise the possibility that drugs acting on the central body clock in the brain may be useful for ameliorating age-related decline in daily biological rhythms,” added Dr Hughes.

Profesor Hugh Piggins, Head of Physiology, Pharmacology and Neuroscience at Bristol University commented: “The findings of this research add to our growing understanding of the importance of regular physical exercise on many body and brain systems. Further it shows that the period of the body clock is flexible and not set in stone.”