“We celebrate our ability to create machines that move as man, yet we take for granted the miracle that is the human body.” - David Alejandro Fearnhead
After the war in Mozambique ended, scientists noticed significant changes in the ecosystem of the country’s treasured Gorongosa National Park. The war wiped out some of the park’s top predators, upending the normal balance between competition and predation. Not only did the lack of predators cause the population of certain species to swell, but these animals behaved in unusual ways. They wandered far outside their typical territorial boundaries and changed their feeding habits, consuming plants that were not common to their diets. These unusual feeding patterns created detrimental changes in the flora and fauna of the park, eventually disrupting its entire ecosystem.
Scientists traced the unusual behaviors of the animals to a lack of predators, which play an important role in maintaining the normal migration and eating habits of animals in the park. Studies in Gorongosa and other ecosystems throughout the world show that predators play an important role in maintaining balance. Without predators, the animals do not experience fear which, as these studies have found, is an important cue that maintains normal feeding and migratory patterns of animal populations. To rebuild balance in Gorongosa, scientists introduced wild dogs, a former predator that roamed the park prior to the war. Just sensing the presence of the wild dogs was sufficient to significantly change the behavior of animals and restore balance in the park’s ecosystem. In nature, fear is an important element in maintaining healthy boundaries.
Our bodies can be thought of as unique ecosystems, made up of a multitude of interdependent systems—circulatory, respiratory, muscular, and neurological, to name a few--and their associated organs, bones, ligaments, tendons. Much like Gorongosa National Park, these ecosystems work well when functioning within well-defined boundaries. We may eat and drink too much, smoke, drive recklessly, or skip sleep until our systems start to break down, forcing us to regroup, change our habits, and come back into healthy margins. A cancer diagnosis, a car accident, or a number on a scale can initiate enough fear to make us change our behavior. But unlike the animals of Gorongosa, raw fear doesn’t always keep us on track. Human intellect easily overrides the wisdom of the body. Even when faced with a real threat, we find ways to ignore physical sensations and seek comfort in pleasure.
Our knee-jerk response to pain is finding a way to avoid it. In fact, we are addicted to fleeing from pain, planning our escape at the first whiff of discomfort. Nowhere in our lives is this more apparent than in our approach to exercise. Even those who regularly workout experience moments when they are so uncomfortable that they desperately search for an escape hatch. Because it is planned and intentional, exercise offers a glimpse at how we cope when we are uncomfortable and can function as our training ground for tolerating difficult situations.
The lines between movement, physical activity, and exercise are hazy, but generally we think of exercise as being a planned, structured activity with the intention of improving or maintaining fitness. The terms physical activity and exercise are frequently used interchangeably, but their distinction is important. Both physical activity and exercise are types of movement that require energy that is greater than what is used at rest. However, exercise is intentional; it is planned physical activity that has a specific structure, duration, and intensity. Physical activity is not always anticipated or purposeful; it may be spontaneous or simply a means to an end, such as walking the dog or cleaning the house. Different levels of intensity can be experienced in both physical activity and exercise—moving furniture or rushing to the bus stop can be quite taxing--but it is the intentionality of exercise that creates the distinction.
Our body is built to move, not to sit in static positions for long periods of time. Any physical activity will get our blood flowing, muscles working, and can keep our joints happy. But exercise occupies a different space in the geography of our lives. Because it is planned and structured, it plays an important role in how we experience our body and all its sensations. How often we exercise and the types of programs we plan reflect our relationship with pleasure and pain. Do we gravitate toward exercise that keeps us in our comfort zone, or are we willing to push ourselves to our edge, purposefully making ourselves uncomfortable? How do we react to discomfort?
Some people strongly resist exercise that is uncomfortable, avoiding any activity that feels hard. Exercise can generate strong feelings, and the sensations of struggling to breathe, getting sweaty, or enduring the burn of extreme muscle fatigue can be repulsive or overwhelming for some. Everyone’s tolerance for pain is different; soreness and exhaustion can be rewarding for some but be stressful for others. Years of study in exercise physiology shows clear benefits to making ourselves uncomfortable. Evidence shows that our bodies respond quite well to being challenged, no matter our age or physical condition, and that being squeezed or pushed to our limits is critical to our overall health.
The thought of “pushing our limits” can spark images of insensitive and brutal fitness trainers (a.k.a. Jillian Michaels of Biggest Loser fame) or less than pleasant memories of high school gym classes. But exercises that move us away from comfort and closer to pain need not to be punishing to provide long term benefits. Any moment of discomfort in our body is an open space that is an opportunity for wisdom. Pain, discomfort, and fear are unsettling. They throw us into uncertain territory so we resist, looking for a way to find our footing and establish some sense of safety. Pushing the body’s limits—even at moderate levels--teaches us how to let difficulty pass, taking the drama out of the moment and staying grounded in the present.
Exercise that moves the body rhythmically, elevating breathing and heart rates to a level at which you are aware of the work but can still talk is classified as low to slightly moderate intensity. The benefit of this type of work is that it can be sustained for long periods of time, which improves endurance, enhances circulation, and helps to regulate blood glucose levels. It can also elevate our mood, reduce stiffness, and alleviate low back pain. But since lower-level intensity exercise is but a few beats away from being neutral or even pleasant, we are more likely to be distracted and are likely to tune out body sensations. We can walk and talk with friends, sing to music, read a book, watch a show. There is no squeeze at this level of work, our attention wanders, and the wisdom of the moment can be lost.
The benefits of exercise expand as intensity rises. The harder we work and the longer we stay uncomfortable, the more changes occur in the heart, lungs, and muscles. We can use the “talk test” to measure intensity. Exercise that includes intervals in which it is challenging to talk and hard to be distracted is considered moderate to very hard, depending on the frequency, duration, and intensity of the intervals. This type of exercise brings us closer to our limitations while building resilience. Cardiac muscle becomes stronger and more responsive, while the heart’s chambers increase their capacity to hold greater volumes of blood. Our lung capacity expands, with an enhanced ability to store and transfer oxygen. Muscles work more efficiently and recruit a wider range of fibers while building more numerous neural connections. Importantly, our tolerance increases for the burning sensations associated with the chemical byproducts of intense work. Essentially, moderate to hard exercise can train us to be experts at being miserable.
One of the most overlooked areas of exercise intensity is its impact on brain health. Studies have found that the intensity and duration of exercise impact brain glucose metabolism. Decreases in brain metabolism, known as hypometabolism, are associated with Alzheimer’s disease and are predictive of cognitive decline. Whereas lighter exercise intensities show no changes in brain metabolism, moderate intensities increase cerebral glucose metabolism across several seemingly unrelated brain regions. Moderate intensity exercise builds new neural connections between seemingly disparate brain regions, while more vigorous exercise increases metabolism in the hippocampus, an important area for learning and memory. Essentially, exercising at harder levels keeps our brains active in ways that go beyond the standard fare of solving puzzles, Sudoku, and word searches. Plus, these benefits increase with dose—the more time one spends performing moderate to high intensity exercise, the more improvements are experienced in brain glucose metabolism.
The benefits of exercise have limits. First, the pain experienced at higher intensities is not the same as what is felt with an injury. The pain associated with pushing our limits is akin to the extreme discomfort of hard physical work, not the acute sensation associated with a tear or a break. And before we push ourselves, we need to be aware of our physical limitations. Ignorance is not bliss; before engaging in an exercise plan we need to be well versed in conditions that may possibly increase our risk of injury. Lastly, exercise is neither a panacea nor a means to an end. It won’t guarantee weight loss, ward off disease and, impossibly, help us avoid death. The body cannot go on forever. Like all ecosystems, eventually we’ll all decline. Exercise doesn’t grant immunity to life’s obstacles, but it makes us stronger, more resilient, and better equipped to live with the joys and sorrows that are an inevitable part of life.
Planned exercise is our present moment opportunity to train for the inevitable episodes of discomfort that we will face in life. It teaches us how to stick with pain and push through uncertainty. This may all sound grim, but just as exercise enhances our ability to tolerate adversity, it also makes periods of relaxation so much sweeter. This balance between pleasure and pain makes for healthy boundaries and creates thriving ecosystems. What will you do to establish balance in your unique ecosystem, the amazing body that you call home?
Comments