Newsletter #317: Active Navigation & Brainpower 🏃♂️
Satellite-based navigation systems have become indispensable tools in our daily lives, effortlessly guiding us from one location to another. However, this convenience comes at a subtle cost.
Increasing reliance on GPS technology may be eroding the parts of our brain that handle navigation and which build mental representations of our surroundings. For instance, greater usage of GPS over time is associated with steeper declines in hippocampal-dependent spatial memory. You might not think this is particularly relevant in the world now, since we’ve all got smartphones anyway, but the value of spatial memory capacity extends far beyond simply finding your way around. It is thought that spatial memory offers a sort of scaffold for episodic memory (also known as scene construction theory), and the deterioration of these spatial scaffolds seems to play a role in age-related memory impairment.
On the other hand, research also suggests that cultivating navigation skills can combat this trend, and quite literally change the structure of the brain in the process. When scientists examine brain images of licensed taxi drivers and compare them to controls, they see differences in brain volume in the hippocampus, reflecting local changes in the brain to accommodate vast spatial representations of the environment. Furthermore, when novice cab drivers memorize the layout of the center of London, their hippocampus will have increased in size after their training is completed.
But here is where things get really interesting. There is compelling evidence suggesting that physical activity can support this process. As we’ve discussed previously, exercise increases production of brain-derived neurotrophic factor (BDNF), a protein that plays a role in neurogenesis, or the generation of new neurons (which is necessary for learning and memory). The fate of these baby neurons may be influenced by cognitive challenges experienced close to the exercise bout. So, the way this works is exercise drives proliferation of newborn neurons in the brain. Then, cognitive training helps with the survival and maturation of these brain cells. For this reason, combined physical and cognitive training seems to improve brainpower more than either intervention by itself, and there are good evolutionary reasons for why this might be the case.
That brings us to orienteering. Orienteering is a sport that involves using a map to navigate through unfamiliar terrain and find a series of checkpoints as fast as possible. So, orienteering is a great example of what I just described — an activity that taxes both the body and the mind at the same time.
As one researcher said, "The closest surrogate to hunter-gather activity is the sport of orienteering, which naturally and simultaneously combines high-intensity interval exercise with navigation."
To that end, some recent studies have examined how orienteering affects the brain, and a new trial actually tests the impact of an acute bout of orienteering on spatial memory performance. Let’s take a look at what the researchers found, and how it might be useful for us.
This Week’s Research Highlight
Combining running with active navigation boosts spatial memory.
In a prior analysis of cross-sectional data, researchers at McMaster University in Canada compared cognitive results from 158 people with varying levels of experience in orienteering. They found that elite and advanced orienteers showed advantages in spatial processing and spatial memory.
However, this type of observational study tends to come with a major chicken-or-the-egg problem: it's tough to say whether orienteering actually boosts these dimensions of brainpower, or if instead individuals who had greater spatial abilities have been self-selecting into this form of activity because they're good at it.
To figure out whether the experience of orienteering itself could improve human cognition, the same Canadian research team recruited 63 healthy young people. These volunteers were reasonably fit, and they had no previous experience with orienteering.
Before the intervention, subjects visited the lab to provide blood samples and underwent cognitive testing. Then, they were split into three groups.
Two intervention groups navigated a course on the university campus — one group running (vigorous orienteering) and the other group walking (moderate orienteering). Meanwhile, a control group ran through the course at a pace that matched that of the vigorous orienteering group, but did not engage in navigation. This was done in order to isolate the effects of orienteering from the natural boost associated with exercise in general. Everyone was equipped with heart rate monitors, and were instructed to maintain their pace to keep their intensity in the correct range for their group.
After the session, the participants' memory was tested again, and they submitted more blood samples, which were tested for lactate and brain-derived neurotrophic factor (BDNF).
Let’s start with the blood work, then we’ll move to the effects on mental performance.
Lactate is a byproduct of intense physical activity, and is responsible for the acute “burn” you feel in your muscles when you’re working really hard. So, as you would expect, peak levels of lactate were significantly higher in both running groups (control and intervention) compared to the group that walked while navigating. This is a good sign, because it means the study managed to achieve a meaningful contrast in exercise intensity.
Both running groups also saw significant increases in BDNF. Exercise, in general, increases BDNF, but vigorous activity has a much greater impact, so again this finding makes a lot of sense. It has been suggested that lactate may mediate the effects of BDNF, and indeed higher peak lactate was associated with elevated BDNF in this study.
Okay, now for the most important result: memory.
The researchers had the foresight to test the participants on multiple forms of memory. Some types of memory were responsive to exercise in general. For example, vigorous orienteering and vigorous running, but not moderate orienteering, elicited improvements in high-interference memory.* This makes sense as prior research has shown that intense physical activity enhances performance on tests of high-interference memory, through its impact on BDNF and in turn on synaptic plasticity.
However, when the researchers tested spatial learning and memory, the vigorous orienteering group showed the greatest improvement, showing that engaging in active navigation does indeed have unique benefits for this specific form of cognition.
More broadly speaking, I think there are three main takeaways here:
- Combining physical activity with some sort of cognitive challenge has synergistic effects;
- Intense exercise, as opposed to moderate activity, amplifies the benefits by upregulating growth factors in the brain;
- To some extent, the specific cognitive processes that you engage in will influence the subsequent performance improvements.
So, there are a few different ways you can take advantage of this phenomenon, apart from the specific sport of orienteering.
One thing that I like to do is run through a park, especially one that I'm not super familiar with, and try to find my way based on park signage (just be careful not to get too lost!). An augmented reality game, like Pokémon Go, can make these kinds of explorations extra rewarding, and incentivize you to pay more attention to features in the surrounding area than you otherwise might.
If you just want to enhance learning and memory overall, you can achieve this by combining studying with exercise, or just performing the two in close temporal proximity. One thing that I sometimes do is listen to some kind of audio content (lecture, podcast, whatever) while engaging in easy-moderate aerobic activity for an hour or so. Then, I'll do my harder interval training, and switch to some energizing music (HIIT is not really compatible with careful studying in my experience).
Finally, you can leverage spatial memory to help you remember content that isn't directly spatial. Like, I have found that I often remember where I was walking when I heard about a particular research finding in a podcast I was listening to, and this anchoring effect seems to be much greater if I was somewhere novel (like at a park I've never been to before), rather than someplace mundane (like the same treadmill at the same gym that I always go to).
*High-interference memory refers to a type of memory where recall is hindered by the presence of other similar information, like for instance if you were learning Italian and French vocabulary at the same time and then being quizzed on the words.
Random Trivia & Weird News
🧭 Insects navigate using compass cues.
Long ago, before we had satellites, humans navigated by looking to the stars. Many bugs also rely on the sky to stay on course — and they can even do so at night, when the best and brightest celestial cue (the sun) is no longer available to guide the way.
The humble dung beetle is a great example. They have to roll balls of animal droppings for a considerable distance at night while maintaining a straight line. Interestingly, they are able to do this even on a moonless night. When researchers placed these beetles inside of a planetarium under various different celestial configurations, they found that the insects were no longer able to orient themselves when the Milky Way was omitted — suggesting that the arms of our galaxy are a critical celestial cue for dung beetles, and perhaps for other creatures.
Photo credit: Emily Baird; adapted from M. Dacke et al., Current Biology, 23 (2013)
Podcasts We Loved This Week
- Michael Leon: Sniffing pleasant smells to improve memory. Via Live Long & Master Aging.
- Graham Burnett: Your mind is being fracked. Via Ezra Klein Show.
Products We Like
Meta Quest 2
If you’re not crazy about the idea of getting lost in real life, virtual reality may be a surprisingly suitable substitute.
Past research has shown that playing video games which force you to navigate through a 3-dimensional space can enhance spatial processing and memory. And VR that involves spatial navigation, especially when combined with aerobic exercise, can elicit changes in cortical brain structure and ward off age-related changes in the hippocampus.
Meta Quest offers a huge array of games that you can immerse yourself in, either socially via multiplayer or on your own solo adventures. We have found it to be crazy addictive. Some of the games also offer a formidable physical workout, too!
humanOS Catalog Feature of the Week
Daily Performance and Physical Activity
In this course, we review:
🧠 Effects of exercise on the brain
💡 How physical activity within the day can improve your thinking
🏋️ Strategies to integrate more movement into your day
Wishing you the best,
