This is an installment of Good Fit, a column about exercise.
Like many people in the United States, I get much of my exercise from the daily walks I take. On an average week, I spend about 40 minutes a day walking. I cover anywhere from 10 to 14 miles a week. Since I don’t have a car, apart from taking the bus, walking serves as my primary mode of transportation. I am lucky to live in a neighborhood in Providence where this is possible.
Walking is not just practical, and healthy—people have been taking walks outside for centuries to clear their minds, slow down, and take in the sights around them. These walks are a real highlight of my day, and I try to take them throughout the year as weather permits—generally, when there’s no rain, and lately, when the air quality is good.
The past few weeks, though, I have been in Texas, which has faced record heat. Peak temperatures have exceeded 100 degrees for days on end. This has kept me indoors and limited my exercise; physical activity in this weather can lead to heat exhaustion and heatstroke. There have even been several heat-related deaths—a letter carrier in Dallas died while working his route, and three hikers have died in Texas parks due to the heat.
It’s not just Texas, of course—this month, the planet recorded the highest global temperature in apparently 100,000 years. As temperatures become more extreme from climate change, I am faced with figuring out how to make my daily walks sustainable.
The National Weather Service uses a heat index to ascertain when prolonged exposure or activity in the heat can become dangerous. (You can find the heat index in your area on the NWS website by typing in your ZIP code.) This index combines the relative humidity in the air with the temperature to determine when conditions become potentially dangerous. At temperatures above the 90s with the lowest level of humidity listed (40 percent), the heat index suggests extreme caution. At temperatures above 98 degrees, extreme caution becomes “danger,” and after 108 degrees, it becomes “extreme danger”—and the danger, of course, increases with the level of humidity. Indeed, reported temperatures in the Southwest have at times topped 110 degrees this summer.
For those exercising in hot weather, the Centers for Disease Control and Prevention recommends limiting outdoor activity in general, especially during the peak of the day. If you have to be out, the CDC suggests, drink a lot of water, pace your activity, and engage in exercise either early in the morning or later in the evening, when temperatures are lower. In Texas, this usually means a pre-dawn walk, but even then, temperatures are still in the low 80s. When I do manage to get out of bed and take a walk with some water, it’s usually a short one—with the aim of getting back to the house before temperatures increase.
Turning to individual solutions to combat the heat often just isn’t possible. And there are a few reasons why systemic solutions will be all the more necessary as temps keep rising.
Ironically, the more walkable an area is, the worse the heat makes it to walk there. A study of Montreal neighborhoods that were more walkable found that they also had higher temperatures. Researchers took temperature and humidity measurements for 132 neighborhoods, collecting the information on a sensor as they drove through the neighborhood. Each neighborhood was assigned a walk score, which assessed the walkability of the area. Surprisingly, they found that the mean temperature of the walkable neighborhoods was 1.7 degrees higher than that of car-dependent neighborhoods.
Researchers speculated that this difference is not just because of increased density of buildings but also because of more sidewalks and connected streets. A key component of ensuring an area is walkable, after all, involves installing paved paths for pedestrians. But concrete in particular can absorb heat and create a “heat island” effect, raising temperatures in the area. Similarly, a study in Sydney found that areas with high walkability scores and areas with high amounts of greenery (things like tree cover) were inversely correlated: The areas that were more walkable tended to have less greenery. This is important because we know that merely having more trees in an area can reduce surface temperatures dramatically.
Here in the United States, neighborhoods that are predominantly Black have higher temperatures and less tree cover than white neighborhoods do. In general, the average person of color is more likely to live in an area considered to be a heat island than the average white person is in the United States. All of this serves to discourage people from walking outdoors. One study that looked at the impacts of weather on outdoor exercise behaviors in the U.S. found that people who weren’t white or did not have a college education were more likely to delay exercising in the summer due to the weather. Of course, the importance of walking goes beyond exercise. Although less than 3 percent of Americans walk to work, data collected by the Census Bureau from 2008–12 showed that those who made less than $10,000 a year had the highest walking rate, at 8 percent. For these people, walking in the heat presents a danger that they cannot avoid.
Cities are trying to take corrective steps to make walking safer, and a more viable form of exercise and transportation, even as we experience hotter temps. Because dehydration is a big contributor to heat-related illnesses, the German government, for instance, has been adding more public drinking fountains to ensure people stay hydrated. Richmond, Virginia, is attempting to implement a plan for city residents to be within a 10-minute walk of a park, which is a good step. But the way our streets are designed needs to be taken into consideration too: More tree cover would go a long way to help. Walking outdoors in green spaces, as opposed to gray spaces, also has psychological benefits; one recent study that compared walking in both spaces found that participants reported increased mood and decreased stress when walking in the former.
Climate change is here, and we’re now feeling the effects. We cannot accept a future in which our outdoor time is limited to certain periods of year or small windows of the day and we merely shuttle ourselves from one indoor climate-controlled environment to another (for those of us lucky enough to have that). It’s not just walking; our ability to enjoy outdoor activities of all types—biking, sports, hiking—is threatened by extreme heat. Making our sidewalks greener, adding significantly more tree cover and water fountains—these things are not substitutes for substantive climate action, but they can preserve our ability to safely enjoy the outdoors, to do something as simple as talk a stroll in the neighborhood, even in a time of extremes.