And now, a confusing new study suggests reduced brain activity might lead to longer human lives.

A controversial and preliminary study from the Harvard Medical School suggests limiting one's brain activity might actually promote a longer life span and work as a natural life extender. This conclusion isn't only counterintuitive; it almost verges on crazy. But there's solid science behind it.

This is because a protein we all have called REST (RE1-Silencing Transcription factor) seems to play an outsize role in how long we live. REST inhibits neural activity, thereby reducing brain excitement.

This study indicates more REST is directly associated with long human life span. The expression or manifestation of REST has been shown to correlate with increased longevity. The study found REST levels are highest in the brains of individuals that lived to be 90 to 100 years old. Persons that died in their 70s or 80s had lower levels of REST.

The study said these puzzling outcomes might be because REST represses genes that promote cell death. REST also protects neurons from oxidative stress that can degrade them. Extending life spans is also due to REST’s ability to reduce "neural excitement" by blocking the expression of neural genes.

The study led by scientists Joseph Zullo and Derek Drake from Harvard Medical School found this unexpected link between reduced brain activity and increased longevity. It suggests REST is higher in individuals with longer life spans.

The study proved this by testing the theory on roundworms. It found neural activity increased with aging and interventions that reduced neural excitement worked to extend roundworm life spans.

The same result appeared to be true in mice, which researchers also studied. Researchers were also able to test their findings on donated brains from deceased humans. The study said mice lacking REST were more likely to display neural excitation.

What this study suggests is that maintaining a proper balance in brain activity might prevent age-related neurological diseases and improve longevity in humans. The study shows differences in brain activity can be linked to longevity, and found overactivity isn’t good for the brain.

That's because neurons or brain cells constantly firing off because of increased brain activity takes a physical toll on the brain. More regions of the brain are activated when people engage in harder tasks. This fact is particularly worrisome for older adults who activate more brain circuits than younger individuals.

Scientists don’t know for sure why this happens. It might be because brains of older people are less efficient and overcompensate due to that inefficiency.

Old people
In Japan, people have the second-highest life expectancy and live to an average age of 84.7 years old. Photo courtesy of Getty Images/Chung Sung-Jun