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A new study in PLOS One assesses the interoceptive powers of athletes. Interoception, the study explains, is “the detection and perception of stimuli originating from within the body.” I assumed this would be one of those feel-good studies—that, in addition to being smarter and happier and living longer than average, trained runners would also turn out to be masters of tuning into their body’s signals. After all, pacing yourself in a prolonged effort is a fundamentally interoceptive challenge.
But the results turned out to be more complex than I expected. In fact, they raise some interesting—albeit speculative!—questions about whether listening to your body is as important as we think, and whether it might even be counterproductive in some circumstances.
The study was led by Hayley Young, a psychologist at Swansea University in Britain. She and her colleagues compared sprinters, distance runners, and non-athletes in two separate sub-studies. The athletes were further divided into two groups: elite (meaning they were ranked in the top 100 in Britain) and non-elite.
In the first study, 213 subjects filled out an online questionnaire assessing their self-reported interoceptive awareness. This involved various distinct elements like being aware of comfortable and uncomfortable bodily sensations, being able to direct your attention to bodily sensations, and being conscious of the links between bodily sensations and emotions.
The overall results showed that athletes scored more highly than non-athletes, which you’d expect, and sprinters scored more highly than distance runners, which is more surprising given the supposed link between interoception and pacing. When you look at the individual elements of interoception, the results are even more surprising: elite athletes, for example, report lower emotional awareness, self-regulation, and body listening.
Self-reporting has its limits, of course. Maybe the elite athletes are just more conscious of their own interoceptive shortcomings. So the second study tested interoception more directly in a smaller sample of 58 subjects. They completed two tasks. One involved sitting quietly and counting heartbeats during a prescribed period of time. This sounds really easy—after all, I know how to take my pulse, and I’m very familiar with the pounding of my heart during or after exercise. But when I tried it at rest, it’s far more difficult than I expected. The problem is that it’s possible to fake a decent result without true interoception if—like most athletes—you know roughly what your resting heart rate is. The second test avoids that problem: while hooked up to an ECG, you watch a circle flashing on a screen and try to determine whether the circle is in sync or out of sync with your heartbeat.
The results, once again, were a mixed bag. Under normal conditions, the athletes and non-athletes produced similar scores on both tests—although the athletes tended to be more confident in their answers than the non-athletes. When they repeated the second test with simulated crowd noise as a distraction, the athletes did better than the non-athletes. But on the heartbeat counting test, elite athletes were once again significantly worse than non-elites.
How do we make sense of all these results? The safe conclusion is the one that Young and her colleagues go with: “Athletic populations have altered interoceptive abilities.” Something is different with athletes, but we’re not sure what or why. Still, it’s interesting to consider some possible explanations.
One option is that being hypersensitive about what your body is feeling is actually a disadvantage in endurance sports, where most of what you’re feeling is bad news. That relates to a point I first heard from Noel Brick, a sports psychologist at Ulster University who studies the cognitive strategies used by endurance athletes. In the olden days, we used to divide those cognitive strategies into two bins: recreational runners tend to “dissociate” (i.e. distract themselves) while elite runners tend to “associate” (i.e. focus intently on the task at hand and how they’re feeling). But Brick and others have found a more nuanced picture, in which runners shift between distraction and self-monitoring depending on the context—and focusing too much on how you’re feeling during a challenging run might even make the task feel harder.
There’s also a body of research from the motor learning literature that says that familiar actions run more smoothly when you don’t focus internally on the component movements. Tying your shoes on autopilot is easier than remembering the bit about the bunny going around the tree. You’ll hit more free throws by thinking about the ball going through the hoop than by thinking about keeping your elbow bent at the right angle. And you’ll run more efficiently if you’re not hyperfocused on how your limbs are moving through space. This line of thinking applies to both sprinters and distance runners, offering an explanation for why both groups might be less tuned into their bodies.
Conversely, it could be that training and competing actually interfere with interoception. Perhaps repeatedly pushing your body beyond its comfortable limits forces you to ignore all the distress signals bombarding your brain. Over time, ignoring them becomes a habit, and you’re less able to judge how you’re feeling. Or perhaps it’s only modern runners whose interoception is impaired, thanks to their reliance on external sources of feedback like GPS watches and heart rate monitors.
Of course, it’s worth asking whether sitting in a chair counting heartbeats is a relevant test of an athlete’s interoceptive abilities. The signals that endurance athletes presumably tune into are those that affect performance and reveal whether a given effort level is sustainable, such as… well… what, exactly? When I’m in the middle of a race, I’m not counting heartbeats, or estimating lactate levels, or assessing core temperature. I’m tuned into a more general overall assessment of how hard I’m working relative to how hard I expect to be working at this point in the race—what researchers call my perceived effort.
What is perceived effort? One view is that it’s the overall integration of all those other signals: heart rate, lactate levels, core temperature, and so on. This is the view that leads us to believe that elite endurance athletes should be better at interoception than sprinters and non-athletes.
But another view, laid out in a new systematic review in the journal Sport Medicine, is that the sensation of effort doesn’t rely on feedback from the body at all. Instead, it’s generated entirely in the brain, and basically quantifies how “strong” a signal your motor cortex is sending out to the muscles. If your leg muscles are tiring, they won’t work as well, so the brain has to send a stronger signal in order to maintain your pace. Subjectively, you feel this as a higher level of effort.
I initially found this view—that it’s the brain’s outgoing signals, not incoming signals, that generate the sensation of effort—implausible. But the evidence is intriguing. The new review, led by Benjamin Pageau of the Université de Montréal, pools data from studies where incoming signals from muscle to brain are blocked with epidural drugs. Notably, perceived effort doesn’t decrease. So perhaps endurance athletes aren’t tuned into interoceptive signals because they don’t need to be: they’re getting all the information they need from within their brains.
For now, the only real conclusion we can draw is that the topic isn’t as obvious as we might have assumed. One of the key points Young makes is that interoception is too broad a concept. It’s highly unlikely that we’ll ever end up concluding that listening to your body is “bad” overall. But we may find that some ways of listening, in some contexts, are more useful than others, and some might even be counterproductive for athletes. In the meantime, I’ll be sitting here quietly trying to count my heartbeats.
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