In this chapter we're going to talk about the relationship between physical activity and health. For some people, physical activity is important, it's meaningful, it's part of their everyday life, but for others, physical activity and exercise are behaviors that they want to avoid or that take up time that they would rather spend doing other things. But regardless of how we feel about physical activity, there are many important benefits that can be achieved through living a physically active lifestyle. We're going to talk about those in this chapter.
This slide gives you an overview of what we'll cover in this section. We're going to define physical activity, exercise and health, because these terms are important for us to understand the role that they play with physical activity. But before we begin, I want you to think about, for a minute, just take a minute and think about what it means to you to be healthy. What can you do because you're healthy? How does it feel to be healthy? Health is a really broad concept, and we often throw it around, you hear it in the media, but we don't often stop to think what it means. So I want you to take a minute right now and think about what it means to be healthy. By the end of this chapter you'll be able to describe and define what it means to be healthy, but I want you to understand how this relates to your own life and the lives of the people that are around you.
Our views about health have evolved over time. We're going to cover three different perceptions of health and how they've changed throughout time. The first one is really viewing health as an absence of disease. So this was in the early 1900s, people viewed health as simply the absence of disease; not being ill. If an individual was not sick, then they were healthy, pretty simple. If an individual was sick, the best course of action was to seek treatment from a medical doctor. And this view of health really privileges your physical health to the exclusion of other types of health such as your social, spiritual, emotional health, that we'll talk about later in this lecture.
As we progress through time, health became more of a holistic concept. So in 1948, the World Health Organization defined health as "A state of complete physical, mental and social wellbeing, and not merely the absence of disease or infirmity." And although this definition was created over 60 years ago, it's still the most widely-used definition of health today. It's important that we recognize that this view of health really considers the many different aspects of our health, not just our physical health.
The third and most contemporary view of health is the view that health is wellness, and in this view of health, health is considered dynamic, or always changing. We're constantly striving towards functioning at a higher level, so there's a sense that the person is actively working towards their own health. In addition to this, there are additional dimensions of health that have been added to the model, so now there are seven dimensions of health which we'll see on the next slide.
Take a minute now to write down the three dimensions of health that were part of the 1948 definition of health from the World Health Organization. The other four dimensions pictured here have been added more recently.
On the next few slides we're going to discuss the seven dimensions of health, and we'll discuss each one just briefly, so that you have a sense for what each dimension covers. The first one is your physical health, and this is the one that everyone thinks of first: the condition of your body, your organ systems, how well is your body functioning? Second one is intellectual health, and here we're talking about your mental capacities. Our mind is a really, really powerful tool, and being open to new ideas and concepts are one way, a couple ways, to promote intellectual health. Using your mind to analyze, to synthesize, to apply information, also signs of intellectual health. The third dimension of health is emotional health, and here we're talking about your ability to express your feelings appropriately, under many different situations that occur in our everyday lives. Feeling confident, respected, loved; all of these are signs of emotional health.
The fourth dimension of health is social health, and this refers to the ability to interact effectively with others, even when those others are different from us. In the picture here you see some people playing cards with who you presume to be their friends. That and having meaningful, positive relationships with friends and family in your life, those are all examples of having positive social health. The fifth dimension is spiritual health, and here we're talking about your soul, or your spirit, and this isn't necessarily tied to religion, but instead is tied to the belief that we're part of something that is larger or bigger than ourselves, and often results in feelings of compassion for others and a sense for right and wrong.
The next dimension of health is career or occupational health, and this is achieved by having a meaningful career that makes a person feel they're contributing to society in positive and important way. You can see pictured here is Andy Rooney, and recently in the popular news—he since passed—he gave his final sign-off by saying "Not many people in this world are as lucky as I've been." I'd ask you to watch the video here. Think about the way Andy's career has really enriched his life, and how it's become part of his overall health. Can you think of other examples of people who exhibit great career or occupational health?
Environmental health is the final dimension of health in our contemporary view of health as wellness, and this is probably the broadest of all the dimensions of health. It includes many things in the world around us. Two examples that are pictured here; one, the physical environment. The air we breathe in is one example of the environment that affects our health around us. So in the picture you see a young man riding his bicycle along the street, and the air is just filled with smog and pollution. Obviously that's not a very positive physical environment for your health. The other example shows a map of the United States, and it shows how the smoking policies, state by state, have affected smoking in each of those states, and clearly policies have an impact—policies in our environment around us have an impact—on our health, and in particular policies about health such as smoking.
When we consider all of the dimensions of health together, you can think about it as quality of life, and we often throw this term around, but what we mean is a subjective measure that reflects our levels of fulfillment, satisfaction, happiness and feeling good about ourselves despite any limitations we might have. Quality of life is a concept and a term that is often used in research studies as an overall measure of how well people are doing.
So if health and quality of life are really important and meaningful parts of our lives, what can we do to improve them? How can we make our health better? And you can see really clearly in this figure that a large percentage of our health is determined by our behavior. Other big percentages are obviously from our genes, our genetics, you can see here in heredity, but also in our medical care, our social circumstances, and our environmental conditions. Some of those social circumstances and environmental conditions we might have some control over. So if you include those, over half of the relationship between premature death and longevity are due to our behavior, environmental conditions and social circumstances, things that we potentially could have some control over.
This table again illustrates how important behaviors are to our own health. So here you're seeing the risk factors for death among people in high-income countries, of which the United States is one, and you see the top five risk factors: tobacco use, high blood pressure, overweight and obesity, physical inactivity, high blood glucose, in that order, 1 through 5, top highest risk factors for death in high-income countries. What do you notice from this list? If you are thinking to yourself "These are all either behaviors or related to behaviors," you're right. So tobacco use is a choice whether we use tobacco or not. High blood pressure; again, this is not a direct link, but high blood pressure is linked to behaviors. Overweight and obesity, again indirectly related to behaviors. Physical inactivity, that's a behavioral choice. High blood glucose, again indirectly related to physical activity and other behaviors that we can make choices about to make a difference in our risk factor for death.
Unfortunately we don't always make the right choices. Too many of us live sedentary lifestyles. More than 1 in 2 adults are not getting enough leisure time physical activity to benefit their health. Public health experts have called physical inactivity one of the biggest health problems of the 21st century. And we know that people are living more and more sedentary lives that are related to premature death. So we don't always make the right behavioral choices to really aid in our health.
On the next two slides we're going to compare the top 10 leading causes of death in 2007, on this slide, to the top 10 leading causes of death in 1900, and what I want you to see is that the types of diseases that we're dying from today are much different than they were in 1900. So, for example, here in pink you can see all of the reasons, leading causes of death for which sedentary lifestyle plays a role. That doesn't mean it's the only thing that contributes to these types of deaths, but that sedentary lifestyle could play a role. In the top three here you see heart disease, cancer and cerebrovascular diseases; stroke would be an example of that. So we have these top 3 diseases where sedentary lifestyles, people sitting too much, not being active, are playing a role in the leading causes of death. Very few of these top causes of death are completely unrelated to physical activity, so only 3 of these top 10 are unrelated to leading a sedentary lifestyle.
Now compare this graph to the one we saw on the previous slide. Here we're looking at the top 10 leading causes of death from 1900, and you can see a clear shift in the types of causes of death that people are dying from in 1900 compared to 2007 in the previous slide. So what do you see? Yes, some of the diseases on these list, i.e. cancer, diseases of the heart, are still present, but they represent a much smaller percentage of the total deaths, and there's a clear shift from communicable diseases, such as pneumonia and influenza, to non-communicable and preventable diseases such as heart disease. In short, the bad news is that we're dying too young of preventable diseases, but the good news is that we know that choosing healthy behaviors such as not smoking, eating well, being physically active, can reduce the likelihood of premature death. We're going to talk about all of these things throughout this semester, but it's important to keep these statistics in mind, because we're choosing behaviors that are leading to lower quality of life and are leading us to die prematurely.
So over the next few slides we're going to talk more positively about the things we can do about our health, to affect our health in a positive way. So we'll talk about physical activity, exercise and physical fitness. But before we begin, watch the video here, and I want you to think about is the young man in this video doing physical activity or exercise? Why do you think? If you said physical activity, you're correct, but why? We'll talk about that in the next couple slides.
Physical activity is defined as any bodily movement produced by the contraction of skeletal muscle that increases energy expenditure above a basal or resting level. So think back to the video. The young man who was featured in the video clearly was contracting his muscles to dance and was expending more energy while dancing compared to when he was seated and simply watching the basketball game. But why wasn't this exercise? Well exercise is a subset of physical activity that is planned, structured, repetitive and purposeful, and a purposeful attempt to improve or maintain physical fitness, physical performance or health. I don't know about you, but I don't think that he would necessarily plan to get up and dance during that basketball game. And it's important to note here that exercise is physical activity, but all physical activity is not exercise.
In the popular media, we often hear physical fitness used as a simultaneous term for either physical activity or exercise, but they are not the same thing, so we want to be sure in this class that we highlight the differences and that we are all on the same page relative to the differences between physical fitness, physical activity and exercise, because we want to have meaningful conversations about each of these terms; we want to be very how we use them in this class. So physical fitness is not a behavior, let me say that again, it's not a behavior, it's a set of attributes or characteristics of a person, that a person has or achieves, and relates to the person's ability or capacity to perform specific types of physical activity efficiently and effectively. So again, physical fitness is not a behavior, but is a set of characteristics, and we'll talk about two different types, both health-related and skill-related components of physical fitness.
The first type of physical fitness are health-related components, and this is where we'll spend the majority of our time. Not in this lecture, but in future lectures you will be learning about each of these individually, so I'll just present them here, but we will talk about them in much, much greater detail in the next few chapters.
Here you see all of the skill-related components of physical fitness, so you have health-related and here are the skill-related. Again, we're not going to talk much about these here because we're going to talk about them in future lessons, and what you'll see is that we'll talk about these components of physical fitness a lot less because they are less connected to overall health than health-related components. So we'll spend a little less time on these, but we will still talk about each of these in a future lesson.
So we know by now that physical activity is important, but how much should we do? How much is enough? Do you ever hear people ask that question, "Well, okay, I know I should be physical active, but what should I do? How much should I do?" Our government recommends that adults get at least 150 minutes of moderate-intensity aerobic activity; so that could be similar to brisk walking; or 75 minutes of vigorous-intensity aerobic activity every week, and that equates to about 30 minutes every day of moderate exercise or physical activity. They also recommend that we get two or more days a week, all the major muscle groups in strengthening activities, and we'll talk about these recommendations a little further in the semester, but I wanted to present them here.
Because we know that physical activity is such an important behavior for health, it's also important to know how to measure physical activity. How do we know if people are achieving the right amounts or enough physical activity to promote health? Well we're going to talk about four different ways that we measure physical activity, the most common ways that physical activity is measured, and the first one here is self-report, simply asking people to report, usually on a paper-based questionnaire, how much in terms of how often, how intense or how long people participate in physical activity. The good things about this are that it's non-invasive, meaning that you don't have to sample blood or ask them to wear a particular unit or ask people to be monitored for the whole day; it's very non-invasive. You can do it very quickly, and it's very cost effective. So oftentimes when you see really big studies of physical activities, these self-report measures are included because it's really cost effective; you can ask a lot of people some questions about their physical activity in a very cost-effective manner. The bad thing can be that people often over-report. Because people know that physical activity is a good behavior, it's something positive, it's something they should be doing, oftentimes people bump up their numbers a little bit, if you will.
The second way that we could learn and measure peoples' physical activity is to watch it, observation. A researcher could go into any type of setting, so, for example, a gym class in school physical education class. That researcher could go and observe and record physical activity behaviors. It could record the types of activities, how long kids spend doing a particular activity versus another. And so the good thing is that there's much less chance for over-reporting, right, the kids not reporting their own physical activity, so there wouldn't be that chance for over-reporting. The researcher would simply be observing, recording what they see or don't see, and they would get to watch people in their natural environment, so what actually happens when people are in their natural environments being physical active? The bad things about observing physical activity as a method for physical activity measurement is that it's not very cost-effective, so it costs money and it takes manpower to put people into that situation, and it's not often feasible for larger studies. The final reason, or negative or con, is that the researcher presence can often affect those that are participating in physical activity. So let's say the children in that physical education class knew that the researcher was there to study physical activity, maybe they would act a little different that day. So that's some of the downsides to this measurement tool.
The third way that we measure physical activity is using an electronic pedometer. This device is really small, it's similar to a pager, counts the number of steps a person takes. You can wear it usually on your hip, but there are some other locations. The good thing is that they can be very inexpensive, they're very easy for people to use, and they've become kind of popular, so people are familiar with these devices, and it gives the researcher an objective measurement of activity. So the person puts it on, they wear it all day, and they can tell you a number at the end of the day of the number of steps that they took. The bad thing is that this doesn't necessarily give us information about the intensity or the duration of their activity, so those components are missing when you use a pedometer, and it's not designed to capture all bodily movements. So, for example, if I went to the gym and decided to go for a swim, you can't wear the pedometer in the water, it wouldn't cover that activity, it wouldn't cover upper body activities, and so there are some cons associated with a pedometer as well.
The fourth common way to measure physical activity is using an accelerometer, and here it's a small, again it's a very lightweight device, it's about the same size as a pedometer. It uses electronic sensors to measure the quantity and the intensity of movement. So instead of, unlike the pedometer, it is able to capture the intensity of movement. The good thing is that it, again, measures and stores your data on intensity, frequency, how often, how long people participate in activity, and it can be much more sensitive than a pedometer. The problems are that they're very expensive, so a couple hundred dollars per unit, so for one accelerometer we're talking, let's say, $300, and it still doesn't capture all of your bodily movements. So again, if you went swimming you can't take most of them in the water, and again, some upper body movements may not be captured by the unit as well.
In summary, we know that physical activity has many, many benefits. Just a few of them are listed here, very, very few of them; your textbook has lots more examples of the health benefits of physical activity.
We also know, as this graph clearly indicates, that the more activity you do, the more health benefits you get. So, although we recommend, or the government recommends, about 150 minutes per week, you can see here that if you do more, you get more benefits.
So if we know physical activity is so good for us, why do we lead sedentary lives? There are some major factors listed here, including our widespread use of cars, labor-saving devices such as the remote featured in the picture here. You could probably come up with lots and lots more examples and reasons why we lead sedentary lives.
We'll end the lecture here today with this video about sedentary lifestyles, and the video presents lots of alarming statistics on the rates of physical inactivity in this country, and highlights some of the societal changes across time and throughout our history that have affected our activity levels. And I don't leave you with this to end on a down note, but we have to keep in mind the way our sedentary lives developed as we try to think about ways that we can improve the lives and help people become more physically active. So I give you this video not to get you depressed about the sedentary lifestyles in our country today, but to really think about some of the causes and think about how we can make changes so that the health of our nation is better in the future.