“I went out for a walk and…going out, I found, was really going in.” - John Muir
Even though the treadmill is, by far, the most popular fitness machine in the U.S., it has earned the nickname of “dreadmill” for the monotony of its design as an infinite sidewalk that takes us nowhere. Perhaps that is why these heavy, bulky machines, purchased with the best intentions, end up gathering dust and are frequently listed for resale online or dragged out at garage sales in like-new condition, only to face the same eventual fate with new owners. By far, boredom is one of the most frequently cited reasons for their disuse. It is hard enough for people to stay motivated to exercise regularly; walking on a moving surface that goes nowhere certainly falls short of inspiring anyone to get active.
Perhaps one of the reasons treadmills are so boring is that they were originally used as a means of punishment and rehabilitation for prisons. Designed by William Cubitt in the early 1800’s, treadmills were used both as a tool to inflict pain upon the prisoner as well as to teach the value of an honest day’s labor. The term “treadmill” reflected this intention, as the successive steps taken by groups of prisoners on the machine worked to operate a mill that processed grain and pumped water. Cubitt’s treadmill used the power of human stride, typically for up to eight hours a day, to grind corn to be sold for a profit by the prison. Cubitt’s theory behind the treadmill was the 1800’s version of “no pain, no gain”; he believed that hard labor on a treadmill for a fixed period of time would rehabilitate offenders and prepare them to become productive members of society.
Historic accounts of the treadmill’s notoriety point to its monotony as being torturous rather than any physical pain it may have inflicted. With the advent of prison reforms, the treadmill was eventually abandoned only to reemerge later as a way of testing for heart disease. By the 1950’s, doctors were putting patients connected to ECGs on treadmills as a way to detect changes in heart rhythms and identify previous heart attacks or other cardiac issues. What was once an instrument of punishment had become a means of saving lives. The final transition of the treadmill into the fitness arena happened in the 1970’s when Bill Staub, an engineer who was also a competitive runner, designed the first in-home treadmill to be used as a way of training for races year-round, regardless of inclement weather.
Although many have a conflicted love/hate relationship with the treadmill, it is the most popular piece of cardio equipment found in the home as well as the gym; estimates are that 53 million Americans used a treadmill at least once last year, and 28.5 million logged an average of one session per week on the machine. Clearly there are a good number of people who depend on it for their daily workouts, although even regular users are quick to complain of its inherent tedium.
People frequently ask whether a workout on a treadmill offers the same benefits as walking or running outside. Studies have shown that, provided pace and elevation gains are similar, the caloric expenditures of treadmill workouts and those performed outdoors are generally equivalent. However, since walking or running on the treadmill uses different muscles and biomechanics than walking or running outside, they should be considered as completely different workouts. These differences are significant—many fitness trackers have separate settings for indoor and outdoor walking and running.
On a treadmill, we are being moved by the belt and are required to keep up with its pace. Since the belt is moving us, fewer muscles in the lower leg, ankle, and foot are required to propel us forward. Treadmill movement is more focused on the larger leg muscles and the hips, which are recruited when we bring the back leg forward. How quickly we can swing the back leg forward will determine our workload. Walking and running outside, however, requires more muscle recruitment and stabilization. There is no belt to move us, so all the muscles from the hip to the toes are responsible for generating the power to move us forward.
Whereas treadmills can offer some variation in terrain with changes in elevation, walking and running outside offer continuous changes in the terrain as we encounter dips, bumps, stones, gravel, and uneven surfaces. Exposure to these changes requires more stabilization of our joints. Although offered in higher end models, most treadmills do not offer downhill settings. Walking or running downhill recruits more of our postural muscles and strengthens the muscles in the front of the lower leg, which helps avoid developing painful shin splints. Some studies suggest that exposure to these surface variations can help to alleviate stiffness in the knee, hip, and lower back due to arthritis. However, for those with severe arthritis, pavement and concrete, as well as small variations, may cause strain in arthritic joints. For severe arthritis, a well-padded belt on a treadmill may be a better option.
The treadmill offers safety and control, both of which, at different times of life, make it an excellent option for working out. Changes in vision, hearing loss, back injuries, physical disabilities, allergies, or safety issues make the treadmill an important way to keep moving during times when we need control. Although I prefer being outside, I am always thankful for a treadmill on icy, snowy days or when visiting an unfamiliar area. There are, however, some important benefits that outdoor exercise offers that cannot be replicated on the treadmill. Research on how nature impacts our health is showing that being outside provides lots of benefits, but when combined with exercise, gives the workout an additional boost that can turbo charge our well-being.
As mentioned in last week’s blog, being outdoors in nature is an immersive experience that simultaneously engages many of our senses. When exercising outside, we use more of our senses than we do inside. When moving outside, our vision and hearing shift back and forth from noticing what is far away to what is nearby, as well as what is at our sides. Our hearing scans for what is behind us. This information is coordinated with the sensations our muscles and stabilizers are sending to the brain about the terrain and where our body is in space. Added to the mix are subtle sensations of our breathing rate, whether we are hot or cold, fatigued, or thirsty. We also send messages about our reaction to the elements—snow, rain, humidity, wind. Studies have shown that exercising outside improves the ability of our nervous system to coordinate our movements with a minimal use of our attention. Essentially, we relax more as we develop this coordination, which enables us to “get in our zone”. We move fluidly and rhythmically which can heighten our enjoyment, reducing fatigue as well as muscle soreness.
Sunlight has long been a remedy for many maladies, prescribed by the ancient Greeks and many healing practices over the centuries. The World Health Organization estimates that 50% of the world’s population is deficient in Vitamin D, most likely a result of spending too much time indoors during daylight hours. Studies have found that exposure for even 10 minutes per day can significantly increase Vitamin D production while helping to release serotonin. We tend to scorn the idea of direct sun exposure given what we know about its risk to skin damage and cancer, but newer research is suggesting that some partial sun exposure, at the right time of day, for short periods of 10 to 30 minutes, can be beneficial, even if only 20 – 30 % of the body is exposed. Studies show that exercising in the sun, even in the winter, helps to regulate our mood, providing a boost to endorphins beyond what we get from the exercise itself. Those who enjoy early morning walks or runs get an extra bonus at bedtime; exposure to early morning sunlight regulates our circadian rhythms and the production of nighttime melatonin, helping us to get better, more restorative sleep.
Most research on how nature affects us points to its power to relax, reduce our blood pressure, and improve our mood. Studies conducted in both the U.S. and U.K. report that people who exercise outdoors instead of in human-made environments, such as gyms, studios, or workout rooms, show less anger, anxiety, muscle tension, and depression. After exercising outside, people are less likely to brood or ruminate up to as long as 24 hours after the workout. By itself, exercise is known to improve our moods, but doing so in nature seems to offer an extra dose of serenity, calm, and feelings of well-being. It also changes how we feel about our walk or run; people who exercise in areas with greater amounts of green space are more likely to feel restored and energized after exercising rather than worn out or overly fatigued.
It should be noted that not all outdoor spaces are created equal in their ability to change our physiology and mood. The benefits of nature increase in direct proportion to the number of trees, plants, and other green space; it seems the wilder the environment, the greater the benefits. Running through the streets of Manhattan will feel very different from running in Central Park. Generally, the more green space we are exposed to, including trees, bushes, natural water sources, soil, and unpaved surfaces, the more health benefits we accumulate.
Regardless of all the benefits an outdoor walk or run can offer, we should not forget that exercise, by itself, is a critical component of staying healthy. If outdoor exercise is not safe or accessible, then the treadmill is an excellent option. And if the treadmill feels like an unacceptable form of prison punishment and torture, you can get a great workout on a stationary bike, rowing machine, or one of the many pieces of cardio equipment that may not feel quite as mundane as a sidewalk that takes you nowhere.
Whether we exercise outside or simply walk the dog before we hop on the treadmill, we all benefit from being outside. If you must exercise indoors, include a short stroll outside for a minimum of 20 minutes, three times per week, in a nearby green space. This is the minimum dose needed to reduce blood pressure and cortisol levels, lower stress levels, and improve mood. Immerse yourself in your surroundings, expanding your awareness to see as much as possible—the colors, textures, shapes—feel your feet on the ground and hear all the sounds around you. Leave your phone at home or in your pocket—studies find that looking at a phone completely cancels any benefits we may get from being outside.
I invite you to engage in a small experiment this week. Find several small slices of time—10 to 20 minutes--throughout the week in which you simply stroll through a local park, green space, or maybe even your backyard. Try to notice as much as you can during your time moving through this space. When you are done with your stroll, reflect on your experience. Notice if there is any change in your breathing rate, attention, or your mood. There is no right or wrong experience; the goal is simply to notice how being outside changes you. You may want to journal about your experience or simply be aware. Perhaps your experience will be a pleasant break in your day or something deeper, like that of John Muir, when, in going out, you find yourself going in.