Middle-age laziness might shrink your brain later in life

Can exercising at 40 slow cognitive decline?

We all have our lazy days. I’m sporty and active yet sometimes you’ll find me on a sofa surrounded by food in the midst of a Netflix binge. It’s good to take it easy now and then as long as you remember to balance it with exercise. It’s no secret that health problems can arise when people have a primarily sedentary lifestyle, and now a recent study in the journal Neurology has hinted that your brain size in later life could be affected by how lazy you are when middle-aged.

A team of researchers from the Boston University School of Medicine investigated changes to brain volume in 60-year-olds having already measured their fitness levels at the age of 40. Middle-aged participants performed peak VO2 tests using treadmills; the researchers measured how long the participants could run until their heart rate reached a certain point.

Twenty years later, the participants’ brain volumes were measured using MRI. It’s normal for our brains to lose volume as we age but this study hints that the rate of the reduction might be associated with fitness earlier in life. The participants that could run for longer at 40 hadn’t lost as much brain volume by the age of 60. Indeed, there was a correlation showing that the worse the fitness, the more the brain had shrunk.

The study only had 1583 participants, which is enough to make this an interesting study worth consideration for future work. However, the researchers can’t say for certain that there really is a connection. The study is limited by the low number of participants and the fact that they were all Caucasian. It’s also important to note that only at the 20-year follow up did they have access to MRI scanners. Future studies could use the same technology at both time points and give a better idea of what’s happening to participants’ brains, especially identifying which regions are being affected by volume loss.

The researchers also found evidence of an association between high blood pressure and later brain shrinkage. Having heart disease also appeared to increase the rate at which participant’s brains had shrunk. This could be an important result as it would mean exercise is more important than ever for people with heart disease.

As limited as the study is, it’s worth keeping in mind during your next Netflix binge. Keeping fit helps us feel better in the short term but also improves our later lives. We can’t be sure if fitness directly affects brain size later, but suddenly I feel like going for a jog tonight.


Main image © iStock/PenelopeB