Physical Activity And Mental Health

William P. Morgan

• Publisher: Taylor & Francis
• Year: 2013
• eBook ISBN:
  9781134938216
• Print ISBN:
  9781138994928
• Subtopic: Abnormal Psychology

This text is an effort to summarize and synthesize the existing research dealing with the influence of physical activity on mental health, as well as the potential mechanisms underlying psychological effects. Contributions from some of the leading experts in the field deal with mental health through prevention, exercise prescription, exercise adherence, drug therapy and exercise, the influence of physical activity on depression, anxiety, and self-esteem, and the paradoxical effects of excessive amounts of exercise.

Part One

General Principles

Chapter 1

Methodological Considerations

William P. Morgan

The link between physical activity and mental health is an interesting one that deserves further exploration. However, the efficacy of physical activity in the prevention of mental health problems, as well as in the treatment of psychological problems once they occur, has historically been based on a number of hypotheses that have yet to be confirmed. This book attempts to present an overview of our existing knowledge about physcial activity and mental health, as well as to create a research agenda for the future. Some of the existing research has led to the conclusion that physical activity does not possess affective beneficence, and this has been due in part to the inadequacy of research designs and assessment procedures. Conversely, additional research has been equally problematic, and this work has led to the conclusion that physical activity is not only beneficial, but is a panacea for many emotional ills. It is apparent that much of the existing literature in this area has suffered from a number of methodological shortcomings, and there is a need for experimentation dealing with the conditions under which physical activity will have a positive impact on mental health. It is imperative that future inquiry in this area be approached with rigorous research designs, appropriate and powerful statistical models, and state-of-the-art psychometric methods. There has been a tendency for workers in this field to argue that one model or method is better than another, but it will become apparent as this book proceeds that such debates merely reflect pseudoarguments. In short, the best or preferred method is usually governed by the question being asked. It is also important to recognize that basic, fundamental design principles must be taken into account in order to eliminate or minimize behavioral artifacts, regardless of the method being employed.

It has been emphasized in most earlier reviews that research in this area has been characterized by a number of methodological problems (Folkins & Sime, 1981; Hughes, 1984; Morgan, 1969a, 1970a, 1974, 1984, 1985a; Morgan & O’Connor, 1988; Morgan, O’Connor, & Koltyn, 1990). As a matter of fact, Hughes (1984) concluded that only 12 of 1,100 published articles involving the influence of physical activity on mental health were acceptable on the basis of selected methodological criteria. According to Hughes the published research in this field is characterized by the absence of randomization, small sample size, inadequate psychological measures, and experimenter expectancy effects, among other flaws. While the rejection of 99% of the published literature in this field probably reflects an extreme position, there have clearly been numerous methodological problems in this area of inquiry. Each of the chapters in this book deals with clinical and research topics that rely on unique investigative paradigms, and each has its own unique methodological issues and problems. The authors deal with those methodological concerns that are unique or specific to the research areas covered in their respective chapters. There are additional methodological issues of a general nature, which are reviewed in this chapter in order to eliminate the need to discuss these general considerations at length in subsequent chapters.

It has been recognized for many years that a number of behavioral artifacts are known to have a direct impact on studies involving psychological outcomes (Rosenthal, 1966; Rosenthal & Rosnow, 1969) and physical performance (Morgan, 1972). In this connection the area of physical activity and mental health is approximately at the same stage of development as the field of psychotherapy was in the early 1950s when Eysenck (1952) published his seminal paper dealing with the efficacy of psychoanalysis versus psychotherapy. While both interventions were found to result in psychological improvement (44% vs. 64%, respectively), it was also noted that “untreated controls” improved in 72% of the cases. Needless to say, this paper raised serious concerns about the efficacy of both psychoanalysis and psychotherapy. A parallel observation was made by Levitt (1971) in an equally instructive paper involving the influence of psychotherapy on children. His review revealed that emotionally disturbed children who received psychotherapy, and those who elected not to receive psychotherapy, had comparable improvement rates.

Eysenck’s 1952 paper has been criticized widely because of various methodological problems, but the fact remains that there was simply an absence of compelling scientific evidence in support of these traditional interventions at the time his paper was published. It is probably unreasonable to judge a study that was published more than four decades ago by current methodological standards, and whether or not one finds the results acceptable, Eysenck’s paper had the desirable effect of provoking a great deal of needed research. The subsequent four decades of research have improved our understanding of the extent to which psychotherapy can be expected to work, as well as the conditions under which it can be maximized. While the parallel is perhaps not identical, there are several striking similarities with regard to the influence of physical activity on mental health. It is time to move beyond simplistic and unproven arguments of causality and to recognize that much of what passes as fact in this area is, in reality, speculation based on a series of yet-to-be-confirmed hypotheses. There is a need to distinguish between fact and fancy, and this book represents an effort to “set the record straight” to the extent possible. This chapter deals with the methodological principles one must entertain when evaluating existing research, and provides a modest prescription for what needs to be done in conducting future research in the area of physical activity and mental health.

ETHICAL CONSIDERATIONS

Guidelines

The study of psychological outcomes associated with physical activity must be conducted within the guidelines and principles established by professional organizations such as the American Psychological Association (APA), the American Physiological Society (APS), and the American College of Sports Medicine (ACSM). These and related ethical codes are revised periodically, and it is the investigator’s responsibility to ensure that all experimental procedures are in compliance with current guidelines. A brief overview of selected guidelines follows.

A number of years ago Beecher (1958) proposed that a prerequisite for experimentation on other humans be the willingness on the part of investigators to first test themselves on the planned intervention. However, self-experimentation may be impractical, and it could be misleading. Beecher (1958) cites the famous medical experiment by Hunter, who inoculated himself in 1767, with gonorrheal pus in order to demonstrate that the disease could be transmitted in this fashion. Unfortunately, he contracted not only gonorrhea, but syphilis as well, and this led to the erroneous conclusion “that gonorrhea and syphilis were merely manifestations of the same disease” (p. 7). At any rate, demonstration that one is willing to undergo an experimental treatment should be thought of as necessary rather than sufficient evidence that the procedure is safe.

The judgements made by the Nuremberg Military Tribunal regarding experimentation with humans served as the basis for many of the guidelines currently employed, and the 10 points presented in the Nuremberg Code have been discussed by Beecher (1958). Additional guidelines with regard to the rights of human participants were published in the 1964 Declaration of Helsinki, and since 1966 the U.S. Department of Health, Education, and Welfare and the U.S. Department of Health and Human Services (DHHS) have required peer-group approval of all human experimentation funded by the federal government. Institutions receiving federal funding in the United States must also demonstrate that research funded by other sources as well as unfunded research undergo peer review by an institutional review board (IRB) if human participants or animals are involved. In addition, ethical codes pertaining to experimentation with humans and animals have been developed by professional and scientific organizations such as the APA and APS. While this section focuses on issues surrounding experimentation with humans, it is important to recognize that equally rigorous guidelines exist with regard to the use of animals for experimental purposes. It is noteworthy from a general perspective, as well as for this book in particular, that in the 1985 amendments to the Animal Welfare Act, the U.S. Congress ordered the Agriculture Department to “write rules to require, among other things, that universities provide exercise for dogs and improve the psychological well-being of non-human primates” (Burd, 1993, p. 30). One might argue that the U.S. Congress should also order that school districts receiving federal funds be required to provide exercise for the children enrolled in their schools! While it is sometimes difficult to make ethical judgments of proposed experiments, the experience of most IRBs suggests that it is possible, and it is imperative that investigations concerned with the study of physical activity and mental health comply with published ethical standards.

Informed Consent

Informed consent is a rather straightforward matter in many experiments, but the issue can be problematic in certain types of investigations. Several principles should serve as guides to investigators when designing a study. It should be understood that investigators employ informed consent procedures that comply with guidelines published by relevant groups (e.g., IRB, DHHS, APA, APS). There are three basic considerations to be made when requesting informed consent from a potential participant, and this applies to both verbal and written statements. First, the potential participant should be informed of what will be done in the experiment, including the actual procedures and time requirements. It may be necessary to illustrate the actual intervention (i.e., model) in some cases. Second, it should be emphasized that the individual should feel free to discontinue his or her involvement in the study at any point. Third, if there are known side effects or after effects of the planned procedure, these should be made clear when requesting informed consent. Muscle soreness, fatigue, and injuries are certainly possibilities in most exercise studies. A number of overtraining studies have been conducted in recent years, and it is known that overtraining sometimes leads to depression of clinical significance (Morgan, Brown, Raglin, O’Connor, & Ellickson, 1987). Volunteers for experiments involving an overtraining stimulus should be informed of this possibility, and it would seem prudent for investigators to provide treatment should any undesired effects occur. It was once thought that if anxiety neurotics exercised they would experience anxiety and panic attacks because of excess lactate production (Pitts & McClure, 1967). While this view is no longer regarded as valid for all patients suffering from anxiety disorders (see chapter 7), it would still seem appropriate to caution patients with panic disorder about this possible side effect. Stein et al. (1992), for example, reported that 1 of 16 patients with panic disorder experienced panic following submaximal exercise on a bicycle ergometer. Hence, while the likelihood of panic in this patient group is low, the possibility does exist, and it would be appropriate to inform such patients of this potential outcome.

It is possible that a given treatment might result in after effects or side effects that the investigator may not be aware of at the outset of an experiment. While this can make obtaining a true informed consent problematic, there are some safeguards that can be employed. Volunteers for an experiment can be informed that no negative effects are anticipated, nor have any been reported for the planned treatment, but that the investigators will terminate the experiment if any negative effects occur. A study may also need to be terminated because the positive effects (e.g., survival rate) of a given treatment (e.g., aspirin) might exceed those noted for an untreated (e.g., placebo) sample. This actually occurred in the multicenter aspirin trial conducted by the National Institute of Health, and there are numerous other examples of this type in the medical literature.

There are times when it is difficult to obtain valid informed consent from individuals who represent special populations. Individuals who cannot read or who speak a different language, young children, and patients from various diagnostic subgroups (e.g., Alzheimer’s disease, depression, schizophrenia, mental retardation) might not understand a verbal or written informed consent statement. It is important that investigators who anticipate conducting research with special populations become familiar with the unique guidelines in place for the population they plan to study.

It is recognized that numerous behavioral artifacts are known to influence investigations dealing with psychological outcomes. Because factors such as demand characteristics, pretest sensitization, experimenter expectancy effects, and the Hawthorne effect (discussed later in this chapter) can have a significant impact on individuals participating in experiments (Morgan, 1972), it is sometimes necessary to deceive the participant regarding the true purpose of a study. However, deception paradigms run the risk of violating certain ethical and legal principles, and it is important that the use of deception be carried out in accordance with established guidelines. This will usually include a debriefing session following completion of the study in which participants are informed of the true purpose of the study and provided with a summary of the findings if desired.

While it is imperative that volunteers for a study be informed of its general purpose, it is not necessary that they be informed of the investigator’s actual working hypothesis. Indeed, there is compelling evidence that compliant volunteers will respond to an intervention on the basis of what Orne (1962) has labeled “demand characteristics.” This phenomenon, along with other behavioral artifacts, are reviewed in the next section.

RESEARCH STRATEGIES

Acute and Chronic Physical Activity

It is important for several reasons that attempts to describe, predict, or explain the psychological outcomes of physical activity make a clear distinction as to whether or not the nature of a given intervention involves an acute or chronic stimulus. First, psychological benefits that result from a single episode (acute) may not be demonstrable across time (e.g., 10 weeks or longer; chronic). That is, the sense of well-being and enhanced mood experienced following a single bout of physical activity may be episodic, and this transitory affective state may return to baseline levels within hours. Hence, a given level of baseline mood state may remain the same following chronic physical activity over several months. Conversely, it is possible that acute physical activity has little or no influence on a specific psychological construct (e.g., self-esteem), but this same variable may improve following chronic physical activity.

Throughout this book acute physical activity is regarded as those interventions ranging in time from 10 to 15 min through several hours. Psychological changes in such cases will typically involve those taking place during a single bout of physical activity as well as those occurring in the minutes and hours following a single episode. Chronic physical activity is viewed as acute episodes repeated at least several times per week for months or years.

State-Trait Measures

It has been shown that psychological constructs such as anxiety are best conceptualized as states (situational) or traits (enduring dispositions). The most frequently employed anxiety model (Spielberger, 1983) in use today, for example, is based on this conceptual distinction (see chapter 7...

Table of contents

• Front Cover
• Half Title
• Series Page
• Title Page
• Copyright
• Dedication
• Contents
• Contributors
• Preface
• PART I GENERAL PRINCIPLES
• PART II PSYCHOLOGICAL RESPONSES TO PHYSICAL ACTIVITY
• PART III HYPOTHESIZED MECHANISMS
• References
• Index