As per a new study, for middle aged people, excessive time on the couch watching television instead of working out and staying active may shrink their brains.

The Boston University School of Medicine researchers discovered that less fit middle-aged adults faced loss of brain volume after two decades. The findings appeared in the journal Neurology.

Study author Nicole Spartano of Boston University School of Medicine, said, “We found a direct correlation in our study between poor fitness and brain volume decades later, which indicates accelerated brain aging”.

To conduct the study, the researchers observed more than 1,500 people from the Framingham Heart Study, or FHS, an initiative of the National Heart, Lung, and Blood Institute and Boston University. The study participants were aged 40 on average and weren’t patients of dementia or heart disease. They went through a treadmill test.

After 20 years, the researchers traced the same group, excluding the ones who suffered heart disease or high blood pressure. The group included only over 1,000 people. Thereafter, every group was given MRI brain scans.

The health of FHS participants has been monitored since 1975, with the help of information collected from FHS exams, outside clinical records, interviews of relatives, and the test of participants suspected of suffering from a neurological issue by neuropsychologists and neurologists.

In the treadmill tests, the participants had an estimated ‘exercise capacity’ also called VO2 or the highest amount of oxygen the body is can use in a minute.

The researchers estimated exercise capacity by monitoring the amount of time a subject may exercise prior to his or her heart rate crossed a threshold. They discovered that for every eight units lower performed by the subjects on the treadmill test, their brain volume after 20 years was tinnier equal to two years of accelerated brain aging.