We’re well aware that sports enhance blood circulation. Our brain requires this blood flow full of oxygen to garner energy and function optimally. Hence, it’s only logical to assume that sports, by potentially boosting blood flow to the brain, are beneficial for our brain’s health. The sensation of clarity and refreshment you feel after exercising might be attributed to the rush of oxygen-rich blood to your brain.

But can we objectively measure the increase in blood flow to the brain caused by exercise? More specifically, can we use easily accessible consumer-grade wearable neurotech devices, rather than expensive laboratory-grade ones?

I recently gained access to a wearable device that measures blood oxygenation in the prefrontal cortex using fNIRS (functional near-infrared spectroscopy) technology. This device, called Mendi, is marketed as a neurofeedback tool, the effectiveness of which I remain highly sceptical about.

Nevertheless, the prospect of affordable, portable fNIRS devices at home is intriguing, and I’m eager to explore what they can measure. Compared to wearable EEG, wearable fNIRS provides less noisy data; even a simple blink can introduce artifacts that may compromise the reliability of your EEG data.

As of now, the manufacturer only provides the numbers displayed in the app, with no access to raw data. The Mendi app shows a score called “Resilience,” which can serve as an indicator of the level of activation (or oxygenation) in your prefrontal cortex due to a specific mental state or activity.

Thus, I’m curious: if I use the Mendi device while engaging in a simple low-impact exercise like indoor stationary biking (chosen for convenience since wearing the device during outdoor exercise would be awkward), would I observe a higher “Resilience” score?

Here are the “Resilience” scores I obtained during different activities, each lasting 15 minutes:

• Mindlessly scrolling through social media while sitting on the couch: 1418
• Taking a nap: 1784
• Low-impact stationary biking (at a very slow and relaxed pace): 6394
• Solving a tangram puzzle: 5246
• Simple coding in Python: 4396
• Writing my thesis (which demands enormous willpower): 7814

The data suggest that engaging in physical activity—even if it’s only slow leg movements—does indeed increase oxygenation in the prefrontal cortex, particularly in comparison to sedentary activities such as scrolling through Instagram. Tasks requiring significant mental effort, like writing an academic text or solving a puzzle, also demand more energy, prompting an increase in blood and oxygen flow to the prefrontal cortex.

If your goal is to maintain a healthy brain, you’ll want it to have ample access to blood and oxygen. So, engage in mentally challenging tasks to “exercise” your brain, and pursue physical activities to stimulate that vital blood flow to your brain!