The Hormesis of Cognition

There’s a saying in toxicology that goes “the dose makes the poison.” Even the most lethal toxins, at a small enough quantity, are harmless. And even the safest substances, to excess, are toxic.

In modern pharmacology, we strive for wide therapeutic windows in which a medicine is effective but not toxic. This is especially true for over-the-counter medications, where the risk of a person taking doses higher than recommended is perceived to be much higher than for prescription drugs. Tums are a great example - if the average adult takes double or even triple the recommended two tablets, they will be perfectly fine.

But not all common medications pass this test. Tylenol, the common brand name for paracetamol or acetaminophen, has been widely available since the 1950s, yet it has a narrow therapeutic window. In fact, it is the leading cause of acute liver failure in many countries, including the United States. A common scenario of this is that a person hurts more than usual, so they take a few Tylenol instead of one. Then, a few hours later, they are having trouble sleeping, so they take Tylenol PM, again, often more than one. If they had an alcohol-containing drink during this time, the risk is even higher. Yet Tylenol remains the safest medication to reduce high fever in infants, and is a powerful analgesic that, at the correct dose, is incredibly safe.

What we call a therapeutic window in pharmacology goes by another name for optimizing levels of physiological stress: hormesis. Hormesis is the idea that a small to moderate amount of physiological stress is beneficial to your health, while too much can be harmful or even fatal. Our immune systems function best when exposed to small amounts of pathogens. Running and lifting weights stress our bodies, but also make us stronger.

We know this, and many of us partake in exercise to facilitate our general well-being. Whether the goal is to feel better, look a certain way, or live longer, the general principle is the same: the body requires a minimum amount of physical activity. Today, most of us achieve this through intentional activities; whether it’s at the gym, a park, or at home, exercise is a specific activity we pursue. This is a relatively new phenomenon.

Across human history and across much of the world today, exercise as an activity is absurd to contemplate. Working a farm or hunting is arguably the ultimate functional training, or at least it used to be.

But animals pulling a plow represented a major shift in the physical labor of farming; riding tractors represented another shift. Today, some tractors are operated remotely from a computer in an air-conditioned office.

Similarly, the only commonality between hunting with a spear and hunting with a rifle is that sometimes the animal gets away, and sometimes the animal is killed. Sure, they both require practice to achieve proficiency. But the physique of the average American hunter today doesn’t bear much resemblance to that of the spear-wielding hunters.

The simple truth is that technology has radically changed our daily lives. En masse, we have recognized that we must compensate somehow for our penchants to drive everywhere, send a message to the person down the hall, and have our groceries delivered to our door without once standing up. And thus exercise gyms and fitness classes have become the norm. Whether you prefer pilates or a boot camp style class is a mere difference of flavor.

The more years you accumulate, the more important it is to maintain physical fitness. Not merely the strength to move your body but the coordination to do so without falling. Loss of physical mobility is one of the leading fears about aging, I suspect because it’s understood to represent a loss of autonomy.

And so here we are. A society that recognizes the risks and consequences of our generally sedentary lifestyles, and in response has created a new class of daily activity called exercise. We grant it a status somewhere between work and leisure; you’re allowed to treat it as mandatory, like showing up to work, but you’re also allowed to do it for fun and all weekend long.

While I find a loss of physical autonomy to be terribly annoying (the recent birth of my daughter being a reminder of just how much I prefer being able to do things myself), I fear the loss of cognitive autonomy far more. I know the fallacy of it, yet still struggle to understand my identity without my cognition. If I’m really being honest, I prefer my decision-making to that of most others. Yet much of our cognitive activity is being solved for by technology, too. Not just AI, everything from how we get around in the world to knowing what meetings I’m attending have been solved for by technology for decades.

I increasingly find myself asking, what is the hormesis of cognition?

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At various times across my adult life, I’ve found myself wondering if I should use the highly convenient tool (like navigation apps) or continue to rely on my brainpower. Should I use my grocery list in the store, or should I take the practice of going from memory? Should I have calendar reminders sent to my digital watch, or should I practice awareness of the time and my schedule? Should I attempt to pick a route from my memory of the streets, or should I check the maps app for an optimized route?

Each time, it has felt as though taking the technology option would not only increase ease but also increase performance. If I use my list in the grocery store, I’ll never need to make a second trip. If I get reminders on my wrist, I’ll never miss a meeting. If I use the navigation app, I’ll always get there by the fastest route. Those all feel like performance improvements, but…are they? What performance am I optimizing? The performance of the quotidian of daily life, or the performance of a critical organ?

A recent study found that taxi and ambulance drivers have lower rates of Alzheimer’s disease, even compared to bus drivers and airplane pilots. That last point - the comparison to other transit operators - is what made this study so interesting to me. While other transit operators use fixed routes, taxi and ambulance drivers have to plan and navigate different routes every trip. Even the perceived higher complexity of flying a plane does not compensate for the dynamic nature of route planning and execution.

Considering the age of the study participants, all of whom must have been later in life to observe the incidence of Alzheimer’s, this study does not capture the effect of lifelong use of navigation apps such as Google Maps. In a future version of this study, what will be the relative risk to rideshare drivers who are always following instructions from a map? My suspicion is that they will have the same risk as bus drivers. This is based on studies that have found that the use of navigation apps decreases the development of spatial maps in the brain, which in turn decreases the ability to self-navigate later.

Or to put it another way, the more we use navigation maps, the less capable we are to navigate without them. We become very good at executing the prescribed turns, but cease to problem-solve. I cannot help but wonder, what is the population-level effect of so many switching to using navigation apps day-to-day?

Maps are just one example of cognitive offloading. Others include digital calendars to keep track of scheduled events, pop-up notifications to remind us when a scheduled event is about to occur, snoozing messages or emails to when we think we’d rather address them, live translation that obviates the need to learn a language, meal plans that come with the aggregated shopping list, hell I even wonder about the cognitive impact of notifications telling me to look at an app rather than relying on my own memory that I sent a message I’m awaiting a reply to.

We call our devices phones, but how many people’s phone numbers do you actually know without opening your contacts?

A core principle of hormesis is that, while there is a benefit from a certain amount of stress, there is such a thing as too much. Too much physical stress is deleterious, and the same is certainly true for too much cognitive stress. I don’t believe the answer is to skip all technology, nor is that a realistic solution for my career path that I hold so dear. If not using a digital calendar will result in my ruminating over my schedule, then I lose the opportunity to engage in more complex cognitive tasks. On the other hand, relying entirely on notifications puts me in a situation of constant task hopping and multitasking, both of which are known to be bad for cognition.

While data remains scant about the cognitive side, we do know a few things. First, the more you develop your cognitive abilities, the longer it will take to notice cognitive decline. A crude way to think about this would be that we only really notice will we fall below a certain performance threshold; the higher above the threshold you begin, the longer it takes to reach that threshold of noticing. This is likely why activities like learning to play a musical instrument or learning an additional language consistently have a protective effect in studies about cognition and aging.

Second, sleep matters. A lot. Consistently getting quality sleep is far more impactful than any supplement or medication. Since sleep also impacts your cognition now, optimizing it is a win-win for today and the future. Implementing technology in a way that helps me to fall asleep more quickly and to sleep more soundly - for example, by knowing I won’t forget to complete an important errand the next day - seems to me a healthy choice.

And of course, physical activity. As I’ve written before, the interplay between systems is a hallmark of biological organisms. It’s no surprise that being in good physical health and engaging in exercise also improves cognitive performance, again, both now and as you age.

There’s not a lot of data to say what technologies will or won’t result in worse cognitive decline later in life. And that type of data, by default, takes a long time. There is, after all, only one timeline for truly knowing the impact of using a technology for thirty years. But we do have clues.

For example, the study I cited earlier helps us to understand that the problem-solving of figuring out a new route through the city is better than executing a series of turns without thought for the route. We also know that learning to play a musical instrument or speak another language has benefits. Building and using diverse neural pathways seems to be a safe bet.

There is also abundant data about the impact of physical activity on healthy aging and longevity. As biological patterns repeat themselves, we can draw some reasonable insights from what we know about physical activity to help guide our early efforts in preserving cognitive activity.

Variety in your training is critical. In terms of physical exercise, this means cardiovascular, resistance, balance, and flexibility training. Training each of those individual areas gives some benefit: cardiovascular exercise is protective against cardiovascular disease, and resistance training ensures you can get up and down the sidewalk and lift heavy pots and pans. Even better is to train across all of those areas. This is when you begin to gain synergistic effects, such as being less likely to fall because of your combination of strength, balance, and resistance to fatigue. Or that when you do fall, your bones are stronger to survive the impact, and you have the coordination to get back off the floor.

In terms of timing, it’s never too late to start, but beginning earlier in life is better. For example, a 70-year-old woman beginning resistance training for the first time will see health benefits. But there are even bigger benefits to the twenty-five year old woman; she will be less likely to develop osteoporosis in the first place. And if she does develop osteoporosis, it’s typically less severe. There’s another benefit to beginning earlier: you have more time to train yourself to a higher level. And the higher the level of training you achieve, the higher your starting point for age-related decline. This difference matters because most people retain a high quality of life until their daily activities are severely impacted. Starting from a higher level gives you more time in the cycle of age-related decline before your quality of life is impacted.

But perhaps most of all, consistency is key. People often get distracted by fixating on which exercise they should start with. Or worse, attempt to force themselves to do a form of exercise they hate, convinced that it’s good for them. Countless studies yield countless results, but the answer on the individual level is actually quite simple: the best exercise is the one you will do consistently. Consistent exercise, of any type, beats the exercise you do for three weeks at the beginning of the year and then leave the gear to gather dust in your closet.

Just as technology has necessitated that we intentionally pursue physical exercise, we are at the point where we need to meaningfully prioritize cognitive engagement. As I seek to define what my cognitive training will be, the lessons I carry are the importance of variety, early intervention, and consistency.

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If the criteria for cognitive training are variety, early intervention, and consistency, what are the categories? For exercise, we use cardiovascular, resistance, balance, and flexibility. What are the parallel categories for cognitive training?

Currently, I am thinking about the ability to receive and then process information (including visual and auditory pathways), storing information (short and long term), and ultimately conveying that information back out.

To think of this in practical terms, I want to make sure that when I’m presented with new information, I’m able to quickly receive it and process it according to my needs. This could be looking at where a restaurant is located on a map and quickly planning my own route to get there. Or listening to a lecture in my area of technical expertise and strategizing how it impacts my own work.

I want to remember my friend’s girlfriend’s name later in the conversation, and the next time I see her. When reminded of something in conversation, I want to be able to specifically cite what I’m reminded of and not look it up on my phone first to confirm the details.

When it’s my turn to join a discussion, I want to be able to coherently and efficiently gather the threads of the conversation and weave them to convey my perspective with clarity.

While there are a lot of “brain training” programs, I am generally skeptical of them. For the most part, I think they ensure that your brain is good at doing one task. Perhaps you could make the case that it’s useful for benchmarking, but I prefer to keep my training in the environment of the real world. It’s similar to why I prefer free-weight squats to a squat machine; the squat machine keeps my quads strong, the free-weight squats ensure I can play with my toddler anywhere, any time, and go sprinting after him as needed. Training my cognitive faculties with real-world tasks provides a level of skill integration that a controlled environment cannot.

I’m not saying the below are the solution. I’m still figuring out what real-world implementation will look like, and it will certainly change over time as I test different tactics and new studies provide more information. But these are some key changes I’m personally implementing.

• No using navigation applications to get around town. My husband and I actually started this a while ago. If we are going somewhere new, we allow ourselves to look up its location on a map before leaving the house. If we’ve been there before, we force ourselves to go on memory alone. Sure, sometimes we have to circle back because we were off by a couple of blocks, but that’s what learning looks like.

• No more using a list at the grocery store. I still often make the list, in part to make sure that everyone in the household contributes to the planning. But once in the store, I’m making myself do it without the list. To be honest, considering the convenience of grocery delivery for any missed items, this is extremely low stakes.

• No more copy-paste of short codes for two-factor authentication. Yes, it’s convenient, but it’s also a convenient opportunity to exercise short-term memory!

• Memorizing the contact information for key people in my life, then forcing myself to actually type in the numbers instead of looking up the names. This used to be normal to me. My dad died nearly 15 years ago; in the last years of his life I called him nearly every day, and not once did I bother to open up my contacts and select to call him. It always felt easier to dial his number, since I knew it so well. Heck, I still know it. Similarly, I would never search for my best friend’s email address by typing in her name; I know that email address better than most physical addresses I’ve personally lived in. I want to get back to this level of familiarity with all of my closest people.

• Memorizing poetry. I’ve always coveted this skill and the few poems I do know by heart, I internally reference often. It’s time to grow this repertoire. I’m excluding songs from this because the melody acts as its own cue for remembering, and because I like the push to expand my breadth of cultural awareness.

• Consumption of long-form writing. Unlike short-form content, long-form journalism and books require me to store various parts of a concept and connect them. This is also an opportunity to train focus - a topic worthy of its own article.

• Writing in medium and long-form. It’s one thing to have a thought, another thing to verbally say it to somebody. And it’s a category all its own to convey it in writing. Conveying complex ideas through writing requires a clarity of thought and organization of communication that conversation does not. This is a key practice, not one to outsource to technology. It’s important to note that not everything written has to be, nor is, published.

In a sense, I’m just pursuing the stated promise of technology, that my capabilities can be amplified with my capacity intact. But just like all technology, some compensations are necessary to truly achieve this goal.

A key element of hormesis is that there is a sweet spot for physiological stress, and I’m arguing that the same is true for cognition. If doing something without technology results in a high enough level of stress, that stress itself becomes harmful. Defaulting to technology tools for every task will erode cognitive capacity, just as sitting in a chair all day erodes physical fitness.

Somewhere between those two extremes lies the promised land.