Do you forget things as you age?

I just read New Neurons in Aging Brains in Scientific American.

The story goes like this...

It was long thought an adult brain could not produce new neurons.

Age-related cognitive decline was inevitable.

In the 90's, though, Gage and Van Pragg, then at the Salk Institute for Biological Studies, showed that "running increased the birth of hippocampol neurons in mice”.

Aerobic exercise increases the body’s production of Brain Derived Neutropic Factor (BDNF).

BDNF promotes “neuron growth and survival”.

Including, importantly, in the hippocampus, a key memory center.

Later research on humans showed how "12 months of aerobic exercise led to…an improvement in memory in older adults".

Other researchers found a likelihood of increased connections between prefrontal cortex neurons, an area responsible for executive functioning, e.g., multitasking, planning & decision-making.

But, why?

Why would aerobic exercise change the brain?

Running or walking isn't inherently cognitively challenging, right?

Well, it used to be.

First, when honinims ("...modern humans and our relatives") first split from the lineage of chimpanzees and bonobos, they moved from all fours to bipedal movement.

Walking on two feet required more cognitive load to balance and avoid environmental obstacles.

Secondly, our ancestors were previously "...probably relatively sedentary apes who ate mostly plants".

2 million years ago, "...the planet started to cool and dry out..." 

Our ancestors were forced to hunt and gather.

Doing so requiring spacial awareness, executive function, and memory to find spots where food was previously, all while doing aerobic exercise in social groups ( i.e., walk and run, squat and climb).

Thus, it seems cognition and exercise have an evolutionary link.

Now, if studies link increased memory function & cognitive performance with aerobic exercise…

Is it enough to just do any cardio?

No.

As if it was not already hard enough to exercise…

It turns out being *cognitive challenged* while doing aerobic exercise is more important.

For example, an elliptical or treadmill takes away many of the cognitive demands of hunting/gathering behavior: 

- stable

- no environmental obstacles

- no memory of where you've been or where to go

So...do we all don VR headsets and play Supernatural?

Do we walk/run outdoors & try to remember the path home?

Forage and hike?

What do you think?

A big thank you to the authors, I hope my summary did justice to your work:

David Raichlen, Professor of Biological Sciences and Director of the Evolutionary Biology of Physical Activity Lab at University of Southern California and Gene Alexander, Professor and Director of the Brain Imaging, Behavior and Aging Lab at University of Arizona. 

Thanks for your continued support.

I help people achieve high performance and optimize their health to be happy, confident and successful. 

Reach out here or at hey@alexloveshealth.com