Coach potatoes may one day be able to reap the benefits of exercise by popping a pill.
Being active is good for both mental and physical health; lowering the risk of heart disease, depression and even cancer.
It is also increasingly coming to light that working out may keep us cognitively sharp into old age, with the NHS recommending people be active to reduce their risk of Alzheimer’s.
For those who loathe working up a sweat, scientists from the University of California in San Fransisco are optimistic the benefits of exercise may one day be available in a pill.
This comes after a study in ageing mice found the more active rodents had a higher level of the enzyme Gpld1 in their blood, which has been linked to a sharper brain.
The elderly mice who received Gpld1 via a transfusion reaped the same memory benefits as the active rodents, suggesting the enzyme could be given artificially.
“If there were a drug that produced the same brain benefits as exercise, everyone would be taking it,” said study author Dr Saul Villeda.
“Now our study suggests at least some of these benefits might one day be available in pill form.”
The scientists previously found biological factors in the blood of young mice can rejuvinate an ageing rodent’s brain.
To learn more, they gave a group of sedentary mice blood transfusions from rodents who had exercised consistently for seven weeks.
After a month of transfusions, the mice showed “dramatic improvement” to their ability to remember and learn new things.
Brain analysis also revealed the formation of new nerve cells in the hippocampus, the region associated with memory.
Read more: Jogging could ward off this form of dementia
To test whether taking the enzyme offers the same benefits as exercise, the scientists genetically engineered the mice’s livers, where Gpld1 is made, to overproduce it.
They then measured the animals’ performance in multiple tests assessing cognition and memory.
Just three weeks of the treatment produced similar effects to six weeks of regular exercise, alongside nerve cell growth.
The scientists were “completely floored” by the results, published in the journal Science.
“To be honest, I didn’t expect to succeed in finding a single molecule that could account for so much of the benefits of exercise on the brain,” said Dr Villeda.
“It seemed more likely that exercise would exert many small, subtle effects that add up to a large benefit, but which would be hard to isolate.
“When I saw these data, I was completely floored.”
A corresponding study found Gpld1 was elevated in elderly adults who exercised regularly.
The results may particularly benefit people who struggle to be active, like the elderly or those with disabilities, according to the scientists.
They were also surprised an enzyme produced in the liver could have such a potent effect on the brain.
“Through this protein, the liver is responding to physical activity and telling the old brain to get young,” said Dr Villeda.
“This is a remarkable example of liver-to-brain communication that, to the best of our knowledge, no one knew existed.
“It makes me wonder what else we have been missing in neuroscience by largely ignoring the dramatic effects other organs might have on the brain, and vice versa.”
The scientists are working to better understand how Gpld1 interacts with other systems to produce its brain-boosting effects.
This may enable them to identify targets for drugs that could one day provide many of the protective benefits of exercise.