Looking Good, Feeling Good:
Exercise, Mood, and Mind
In This Chapter
▶ Recognizing the challenges when studying the psychological benefits of exercise
▶ Using meta-analysis to draw conclusions about the effect of exercise on mood
▶ Understanding why exercise makes you feel and think better
You’ve probably been bombarded with dozens — maybe even hundreds — of messages that give the impression that exercise and physical activity improve your mood and the way the brain works almost as much as it improves the body. But here’s the $64,000 question: Are all the messages extolling the psychological, emotional, and cognitive benefits of physical activity really true? And if exercising really does alleviate boredom, anxiety, depression, stress, and tension, and generally make people feel terrific about themselves, why do people have such a hard time sticking with their exercise programs?
The fact is some people do look forward to the positive feelings they get during and after exercising, but many don’t. However, the fact that many people fail to experience sufficient emotional pleasures to keep them exer- cising doesn’t necessarily mean exercise is incapable of improving the way people think and feel about themselves. It can — and it often does. But the connection between exercise and emotions is a lot more complicated than most of us ever imagined. In this chapter, we begin to uncover the real story behind how exercise can (but sometimes doesn’t) make you feel so great.
Drawing Conclusions from Exercise Research: The Challenges
You probably assume that there’s a definitive answer to the frequently asked question, “Does exercise make people feel better?” Alas, that isn’t the case.
Whether physical exercise is — for any given person, at any given time —
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perceived as agony or ecstasy is the result of a virtual Rubik’s Cube of unique personal and situational variables constantly interacting with each other in an almost infinite number of complicated ways.
Many of us know, from personal experience, that working ourselves into a huff- ing, puffing, sweat-dripping lather is an excellent way to reinvigorate not only our weary muscles but also our worried minds. But be careful here — all those wonderful feelings you may get from exercise are not necessarily the same things everyone would experience from a similar workout. In this section, we outline the difficulties researchers have with answering what seems, on its face anyway, to be a very simple question.
The original Rubik’s Cube puzzle that became a world-wide craze in the 1980s has over forty-three quintillion (43,000,000,000,000,000,000 or 4.3 × 1019 in scientific notation) combination possibilities — a number that pales in comparison to the unique biological, psychological, social, and situational variables that impact how people feel when they engage in exercise. For more on those variables, refer to Chapter 12.
Same question but different answers
Explaining why researchers trying to answer the simple question, “Does physical exercise make us feel better?” end up with a completely different set of answers is actually pretty easy. Put simply, exercise isn’t exercise isn’t exercise, and feeling good isn’t feeling good isn’t feeling good.
In other words, research studies that have been done so far involve condi- tions that are unique to each particular study; therefore, the conclusions drawn are unique to those conditions. When you look at different ways to exercise and how many things contribute to whether doing so makes you feel good, it’s no great surprise that even good, solid research often comes up with totally different answers.
In addition, the findings are difficult to make any sense of because exercisers, the media, and even some researchers often attempt to draw one-size-fits-all conclusions from a hodgepodge of investigations into a variety of exercise conditions. Every time you exercise in a way that differs from the way a par- ticular study was conducted (and it’s almost impossible not to), you’re likely going to find it affects you differently.
Following are just a few of the unique conditions that have resulted in more confusion than clarity regarding whether physical activity makes people feel better or not.
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How long do I have to keep this up? Optimum duration
Depending on whether you work out strenuously for a couple of seconds, a couple of minutes, or a couple of hours, you’ll likely feel quite differently during and after your bout of exercise. The conventional wisdom that you need to keep at it for 20 to 30 minutes to gain the maximum benefits from exercise is largely based on what researchers traditionally thought was required for physiological — not psychological — improvements. And even that is now being called into question.
Exactly how long you have to engage in exercise to experience an improve- ment in the way you feel or think still remains a mystery. When researchers study exercises that last for varying lengths of time, they’ll probably find different answers to the question.
How hard am I pushing myself? Level of intensity
Almost every time you go to the gym, you probably see folks on both ends of the spectrum and everywhere in between. Some people push themselves so hard you expect you’re going to have to call 911 at any moment. Others seem to spend most of their exercise time sucking on their water bottles, check- ing the weight stack, tying and retying their shoes, or preening in front of the full-length mirror. Obviously, the degree to which those being studied work hard and expend energy during physical activity has some bearing on what researchers find — but how much? Trying to draw a single conclusion about exercises of various intensities clouds any research results.
How long have I’ve been training like this? Current fitness level
A person’s general physical condition — basically how fit he or she is — has a lot to do with how exercise makes that person feel. Think about it this way:
When you just start a rather strenuous exercise program, you feel pretty wiped out near the end of your session. Worse than that, your muscles are probably screaming at you the next morning as you struggle to get out of bed and shuffle off to the bathroom. However, engaging in this same level of activ- ity after you’ve improved your fitness level likely produces very different feel- ings. Not surprisingly, whether research finds that exercise makes people feel good is, to some extent, simply a matter of the fitness level of the exercisers.
How long am I going to feel this way? Duration of benefits
A difference may exist in the length of time you continue to experience any psychological or mental benefits of exercise. Some people find that engag- ing in certain forms of exercise for precise periods of time under specified conditions results in rather long-lasting (persistent or chronic) benefits.
Others, who exercise in a slightly different way, may only experience positive outcomes that are rather fleeting (acute benefits).
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Research designed to assess only short-term emotions may very well miss even more important long-term benefits. On the other hand, choosing to measure only long-term effects of exercise may minimize at least temporary positive emotional changes.
What do I do when I’m here? Type of exercise
A question exercise psychologists have been brooding over for quite some time is whether all forms of exercise are truly equal when it comes to making people feel better. The major distinction that has usually been made is between aerobic or cardio (long duration, moderate intensity) and anaerobic (short duration, high intensity) activities. For example, the question may be something like, “Does running for 30 minutes (aerobic activity) make people feel better or worse than lifting weights and doing abdominal crunches for 30 minutes?”
Simply lumping all exercise into one of two incompatible categories — aerobic or anaerobic — is an oversimplification that can lead to a great deal of error and misunderstanding. In reality, any form of physical activity can be placed somewhere along a continuous line drawn between “solely aerobic” and
“solely anaerobic,” based on the degree to which oxygen transport and con- sumption is used to fuel the activity. Even a single type of activity — running, for example — may fall on different ends of the scale (running sprints versus running long distances). Confusion and differences over what exactly is aero- bic and non-aerobic often results in research studies coming up with different answers to the same question. (Head to Chapter 6 for a detailed discussion on oxygen transport and Chapter 4 for more on aerobic and anaerobic exercise.)
How badly do I need to feel good? Mental state
Physical activity is often touted as something you can do to reduce feelings of stress, anxiety, and depression. What is often neglected in this discus- sion is that how bad (or good) you feel going into the exercise may have an impact on how the exercise makes you feel. Similarly, how long you’ve felt this way may also have something to do with whether exercise makes you feel any better.
Thinking that exercise has the exact same effect on people who are only mildly and temporarily depressed as it does on those who have been suffering from deep depression for many years is a mistake. Research results describing changes in mood that result from exercise are likely to be very different, depending on how the subject felt before the exercise and how long he or she has felt that way.
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What else can make me feel this good?
Some, but fortunately not all, research findings into the effects physical exer- cise has on mood, relaxation, and stress are limited because they merely tell us what we already know — that doing something is often better than doing nothing. Getting yourself out of a funk may require nothing more than a bit of a distraction. Playing cards, singing in the choir, meditating, praying, talking with friends, listening to music, or having a nice meal can sometimes make you feel better, too.
Research that concludes that exercise makes you feel better often doesn’t consider that it may not be the exercise itself that’s making you feel better;
doing anything (or many things) is likely to put you in a better mood.
Research that doesn’t directly compare the results of exercise to other things you could do to improve your emotions is probably telling you more about the benefits of distraction than the benefits of exercise.
Hey, who is that over there? The setting and social component
Physical activity can take place in many social and nonsocial settings. Some people like to kick and punch along with a high-energy Tae Bo video in the privacy of their own homes. Others prefer to sweat it out with a dozen other cyclists in a spinning class or to play an invigorating handball game every lunch hour with a couple of close friends.
Because some exercise is done in private and some involves intense social interaction, it’s hard to draw conclusions about the degree to which the spe- cific exercise involved makes us feel. After all, simply interacting with others or taking time by yourself to engage in some much needed contemplation may be all you really need to make yourself feel better. Research that doesn’t take into consideration the unique social context within which the exercise is done is often difficult to understand and make sense of.
What am I really looking for? Pinpointing the focus of the research
If you don’t know what you’re looking for, you probably won’t find it, even when it’s right in front of your nose. Researchers trying to figure out whether exercise improves the way people think and feel must be able to carefully define, label, and accurately measure the somewhat similar — but also some- what different — positive thoughts and feelings people attribute to exercise.
For example, a study designed solely to examine stress reduction resulting from physical activity may overlook important changes in exercisers’ anxiety levels. Similarly, a study that specifically focuses on changes in feelings of depression may not see the benefits of exercise on anxiety. It doesn’t mean these positive effects didn’t happen; it just means the researchers weren’t looking for them.
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Researchers can measure only those things they choose to measure, and their research can find only what it sets out to find. If you go beyond the parame- ters of the study or if you are fuzzy on what mood states the research was designed to test (you assume that a reduction in depression, for example, is the same as a reduction in stress), you end up drawing the wrong conclusions as to whether exercise alters important mood states and what states it affects.
Crunching the Numbers: Meta-analysis
Despite the fact that the terms exercise and physical activity mean different things to all of us, exercise psychologists have begun using powerful research tools to help them figure out, at least to some extent, the conditions under which exercise can improve mental outlook. One very useful statistical tech- nique is called a meta-analysis. Although you may find some of the number crunching involved in meta-analysis a bit confusing, the basic idea behind what it does makes a lot of sense and is actually pretty easy to understand.
Meta-analysis is just a fancy term that means to do an analysis of analyses.
Basically, it’s a clever statistical trick that lets researchers combine and sum- marize a whole bunch of separate research findings to reveal overall trends that may not be apparent in the individual studies alone.
Looking at how meta-analysis works
To conduct a meta-analysis, researchers take similar studies, run some calcu- lations on the combined data, and then evaluate the results to see whether any meaningful trends emerge. Here’s a simple example:
Researcher A conducts a study to analyze the effect of aerobic ( long duration, moderate intensity) exercise on feelings of stress. She has study participants run on a treadmill for 15 minutes in a way that maintains about 75 percent of their maximum heart rate throughout the activity. Before and after their stint on the treadmill, the participants each complete a short questionnaire that asks about how much stress they are experiencing at that moment.
A year or so later, Researcher B, who is interested in roughly the same general question as Researcher A, designs a similar study in a slightly differ- ent way. He decides to have his participants ride on an exercise bike during a structured, instructor-led, hour-long spinning class and gives them a somewhat different — but comparable — questionnaire assessing their stress levels before and after the class.
The two studies are obviously a little bit different (they used different types of exercise for different duration and measured stress in different ways), but they also have a lot in common. Both studies set out to look at the effect of
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an aerobic activity on exercisers’ perceived stress levels. Both researchers had participants rate the level of stress they were experiencing before and after they exercised so that changes in stress levels that occurred during the activity could be examined.
If you were to analyze each of these studies separately, it’s possible that you would find that neither the runners nor the spinners felt much difference in the reduction of stress. If that happened, could you definitively say that aerobic activity doesn’t relieve stress? Well, not so fast. One reason you may not see a difference is that perhaps neither study, by itself, had enough sub- jects to actually yield a statistically significant effect, even if one truly existed (researchers often refer to this as a lack of statistical power).
However, by combining the findings of these somewhat different studies (and as many more like them as you could find) and conducting one gigantic analy- sis (a meta-analysis) of all the separate analyses, you may discover some- thing very different.
Very often, combining the results of many studies through meta-analysis allows researchers to see important overall trends that wouldn’t be apparent simply by examining each study individually. Of course, merely conducting a meta-analysis doesn’t guarantee that the true relationship between exercise and emotions will magically be uncovered.
Uncovering limitations of meta-analysis
As powerful and useful as a meta-analysis can be in helping researchers better understand how exercising changes the way people think, it’s certainly not perfect. Like all tools, a meta-analysis itself has a number of limitations, all stemming from the fact it’s only as good as the people who use it:
✓ Someone has to decide whether different studies are truly
comparable. Do the studies have enough in common to justify clumping them all together? In the previous example, what if Researcher A had adolescent males with mild cognitive disabilities run on the treadmill and Researcher B tested a spinning class that only included females over the age of 50? Would you consider these two groups of exercisers similar enough to be combined into one single super analysis? Some people may say yes; others may disagree. This determination is often a judgment call with no right or wrong answer.
Researchers must ensure that all relevant studies, and not just those that support their hyphotheses, are included. Yet the subjective nature of deciding what to include and what to leave out can lead to a big prob- lem: Some researchers get so focused on proving their hypotheses that they exclude, either intentionally or unintentionally, studies that are not
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likely to support their positions. See the next section for more informa- tion about how the studies reviewed can influence the reliability of the conclusions.
✓ Researchers have to know that a study exists before they can include it in the meta-analysis. This point may sound like a no-brainer — something exists or it doesn’t, right? — but it also turns out to be a bit more complicated than it sounds, because of the things that go into decisions regarding whether to report findings. If researchers include only reported or published studies, they may unintentionally miss relevant studies that didn’t get published for one reason or another.
The following sections take a closer look at these problems.
Picking only the tastiest “cherries”
Sometimes, researchers are so intent upon demonstrating that their ideas are correct that they — either consciously or subconsciously — disregard stud- ies where the results don’t seem to support their pre-existing position. ( This tendency is sometimes called cherry-picking the research you want to include in your meta-analysis.) Although all studies differ in some way or another, the person conducting the meta-analysis has to determine whether these differ- ences are still close enough to justify clustering them together or not.
The decision to include or eliminate a study from a meta-analysis may not as quite as straightforward as you think; it can even sometimes be influenced by what you believe the answer “should” be. Consider the earlier example and start with the assumption that, in your heart of hearts, you truly believe that aerobic exercise relieves stress. When you come across the first study (the 15-minute run on the treadmill), you find, much to your disappointment, that the running did not reduce the subjects’ perceived stress levels. They were pretty much as high after running as they were before the subjects got on the treadmill.
When you read the study more carefully, however, you notice that the instant the runners stepped off the treadmill, the researchers also did a blood draw to measure the runners’ lactate levels. Because of your personal biases (you expected to see a reduction in stress after exercising), you may conclude that the mere act of jamming a needle into a person’s arm is stress-provoking in itself, thereby contaminating the results of the study. If you decide that the results of the study are, therefore, not believable, you may feel justified in eliminating it from your meta-analysis. But what if the study — despite the taking of a blood sample — did find a reduction in stress levels after exercise, as you thought it would? Would you now be more inclined to include it in your meta-analysis? If you would exclude it in the first instance but include it in the second, you’re cherry-picking the data.