Behaviors that Impact Physical and Mental Health

Nutrition and Health

Human nutrition and health are inextricably linked because proper nutrition maintains overall health and well-being.

Learning Objectives

Review the human body's nutritional needs

Key Takeaways

Key Points

  • Food is fuel for the body. Cells use nutrients from food to sustain cellular functioning.
  • Nutritional requirements include macronutrients (such as carbohydrates, proteins, and fats), and micronutrients (such as vitamins, minerals, and amino and fatty acids) in order to maintain proper function.
  • Malnutrition is caused by both excess food consumption and insufficient food consumption. Both can result in disease and disorders within the body and mind.

Key Terms

  • adipose: animal fat stored in the tissue of the body
  • enzyme: A globular protein that catalyses a biological chemical reaction.

Human Nutrition and Health

From Hippocrates' classic line "let food be your medicine, and medicine be your food," to the popular modern warning that "you are what you eat," humans have always understood the connection between nutrition and health. The key to understanding why food has such an impact on overall health lies in the physiological needs of human cells. Cells rely on nutrients in food to function properly. Problems like disease and disability occur when the body receives inadequate nutrition.

Needs of the Body

In order to function properly, the human body must meet specific caloric and nutritional needs.

Caloric needs

Caloric needs refer to the energy required to carry out various chemical reactions within each cell of the body. The body gets energy from macronutrients—the fats, carbohydrates, and proteins in the food we eat. These molecules are broken down into essential amino acids and fatty acids and used as fuel for cellular functions. The number of calories a person requires per day varies based on an individual's age, sex, height, and physical activity. If excess caloric energy is consumed, beyond what is needed to maintain body functioning, it is stored in adipose (fat) tissue.

Nutritional needs

Along with its need for energy from macronutrients, the body requires a variety of micronutrients, such as vitamins and minerals, to support tissue growth, enzyme structure, and cellular functions. These can be found in a variety of fruits, vegetables, fibers, and water.


The USDA food pyramid: The USDA Food Pyramid demonstrates the variety and quantity of food needed to promote proper body function and prevent disease. Grains, vegetables, dairy, and fruits are more necessary to healthful diets than meat and beans.

The Basics of Nutrition: Macronutrients, Amino and Fatty Acids, and Micronutrients


Macronutrients include carbohydrates, proteins, and fats. Carbohydrates produce necessary metabolic energy for the body. Fiber is an important carbohydrate that is often implicated in disease prevention, as increases in fiber have been found to correlate with decreases in colon cancer, heart disease, and adult-onset diabetes.

Amino and Fatty acids

Amino acids are organic compounds primarily composed of oxygen, hydrogen, nitrogen, and carbon. Proteins are made up of chains of amino acids connected by peptide bonds; they form hormones, enzymes, and antibodies within the human body. There are

twenty standard amino acids, nine of which are essential and must be

obtained from food.

Fats, or lipids, are combinations of fatty acids. Although it is often vilified, fat serves a vital function in the body, serving as stored energy, protecting organs, and helping to regulate body temperature. Fats are classified as saturated (generally bad) and unsaturated (generally good), depending on the structure of fatty acids involved. Omega-3 and omega-6 fatty acids are particularly important in maintaining health, while trans fatty acids have been found to harm body function.


Micronutrients include dietary vitamins and minerals which are necessary to sustain health. Supplements can be used to make up for not getting enough micronutrients from diet alone. Vitamin deficiencies may result in physical dysfunction, including impaired immune function, premature aging, and even poor psychological health. The benefits of trace minerals range from bone and tooth formation to acid-base balance.


Malnutrition refers to insufficient, excessive, or imbalanced consumption of nutrients. In developed countries, this often occurs in the form of overconsumption of sugary, nutrient-deficient food, which is linked to obesity and numerous related health conditions like diabetes, hypertension, and heart disease. In the developing world, where access to food is often compromised, malnutrition often manifests as hunger, starvation, and malnourishment. Chronic malnourishment prevents healthy growth and impairs vital body functions; this leads to physical health problems and, eventually, death. Consequently, one of the best things a person can do to promote overall health and wellness is to maintain adequate nutrition.

Psychological impact of nutrition deficiency

There is a reciprocal relationship between the physical and psychological effects of poor nutrition. While malnutrition refers to physical impairments resulting from a poor diet, the underlying nutritional deficiencies can have significant impact on mental well-being (including perception and judgment), and often exacerbate existing psychological disorders. Existing or incipient psychological conditions (e.g. eating disorders like anorexia and bulimia) can cause nutritional deficiency and result in poor physical health.

Exercise and Health

Exercise is bodily activity that can have positive effects on both physical and mental well-being.

Learning Objectives

Discuss the impacts of exercise on mood and the body

Key Takeaways

Key Points

  • Physical exercise is any activity that enhances or maintains physical fitness and mental function.
  • Exercise can come in many forms but usually falls into one of three types: flexibility (affects joint mobility), aerobic (affects cardiovascular function), and anaerobic (affects muscle strength).
  • The benefits 0f exercise for the body include weight maintenance, injury and disease prevention, and improved functioning.
  • The benefits from exercise for the mind include higher levels of  endorphins, which elevate the body to a state of euphoria, and mastery, which promotes self-esteem and improved mood.

Key Terms

  • endorphin: Any of a group of peptide hormones found in the brain that act as neurotransmitters and have properties similar to morphine.
  • aerobic: Involving or improving oxygen consumption by the body (e.g. aerobic exercise).
  • serotonin: A neurotransmitter involved in regulating mood, sleep, appetite, blood clotting, and intestinal function.
  • neurotransmitters: A chemical that communicates electrical signals between neurons.

Managing Health Through Exercise

Exercise is any activity that requires physical effort and is carried out with the goal of sustaining or improving physical fitness. Exercise has many benefits for the body and mind: protecting against injury, improving cardiovascular function, honing athletic skills, managing weight, boosting the immune system, counteracting depression, and elevating mood.

Types of Exercise

Physical exercise can be classified into three primary types based on the overall effect the exercise has on the body: flexibility, aerobic, and anaerobic. Flexibility exercise challenges the body's range of motion through stretching, bending, and balance movements. Aerobic exercise increases cardiovascular capacity through activities like running, biking, or swimming. Anaerobic exercise improves muscle strength through weight training. Exercises can also be classified as dynamic when they involve active or flowing movement (like running or yoga), or static when they involve isolated poses or movements (such as weight-lifting or holding stretches). Certain exercises may have aerobic, anaerobic, and flexibility benefits. Calesthenics, for example, which includes rhythmic gross motor movements and strengthening exercise that use only body weight as resistance (e.g., jumping jacks, push ups, sit ups, etc.) increase aerobic and muscular conditioning, agility, and coordination.


Running: Running is an aerobic exercise that increases cardiovascular function and overall health and wellness.

Effects of Exercise on the Body

All of these types of physical exercise contribute to physical fitness. Body weight and composition is maintained by a combination of the food we consume and the energy we expend throughout the day. Physical activity increases the amount of energy the body needs to function. The more exercise a person does, the more energy the body uses. As a result, fewer calories are stored in the form of fat, and this translates into either weight maintenance or weight loss. Along with healthy body weight, exercise has other physical health benefits. It increases cardiovascular functioning, which reduces the risk for certain diseases like heart disease, cancer, and diabetes. Exercise can also positively affect bone density, muscle strength, and joint mobility. Strong bodies have reduced surgical risks, better immune function, and lower susceptibility to illness and infection.

Exercise also serves as stress relief, which has both physiological and psychological benefits. Research shows that exercise reduces cortisol levels, a hormone that is released when the body is stressed and has been shown to have negative health consequences (including heart disease and depression) when chronically elevated. The brain also benefits from physical exercise through increases in blood flow and oxygen that promote cell generation and proliferation. In general, a steady practice of exercise keeps the body strong and functioning properly.

Effects of Exercise on the Mind

Research shows that physical exercise also plays an important role in promoting mental health. Exercise increases levels of endorphins in the body. These naturally occurring opioids are the body's own pain killers. They work in conjunction with neurotransmitters to induce relief, happiness, or even euphoria when the body is in pain or overexerted. Marathon runners will often experience what is called a "runner's high;" this can allow them to continue running despite the physical exhaustion they might feel. Research shows that exercise elevates levels of serotonin and endorphins and that these elevations remain for several days after exercise, contributing to a lasting improvement in mood. Exercise has been proven to have positive effects on people suffering from depression, and promotes positive levels of self-esteem. This phenomenon is due not only to the chemicals involved, but also results from the positive body-image and feeling of competence that come with accomplishing a fitness goal.

Substance Abuse and Health

Substance abuse, or the habitual, harmful use of drugs, can have detrimental effects on the mind and body.

Learning Objectives

Describe the psychological and physical effects of substance abuse

Key Takeaways

Key Points

  • Substance abuse is the habitual use of drugs in dangerous amounts or situations. Both legal and illegal drugs can be used in a harmful manner.
  • Extended drug use can lead to tolerance, dependence, and withdrawal.
  • Extended abuse of substances can cause detrimental physical and mental effects including heart, liver, and cognitive problems as well as depression, anxiety, and psychosis.
  • Substance abuse is associated with higher rates of suicide.

Key Terms

  • withdrawal: A type of metabolic shock the body undergoes when a substance, usually a toxin such as heroin, to which a patient is addicted is withheld.
  • benzodiazepine: a psychoactive drug that is, in general, safe and effective in the short term, though cognitive impairments, aggression or behavioral disinhibition occasionally occur.
  • barbiturate: Any of a class of drugs that act as depressants of the central nervous system and are used as sedatives or hypnotics.

Substance abuse is the habitual and recreational use of an addictive agent (drug) that is consumed in dangerous amounts or dangerous situations. The psychoactive effects of drug abuse occur when the drugs impact the levels of neurotransmitters in the brain that control normal mental and physical functioning. For instance, chronic drug abuse can negatively impact memory functioning, impulse control, and reaction time; it can also increase the risk for heart disease, cancer, liver failure, etc. Individuals who use substances to the point of dependence are at even greater risk for physical health problems, or even overdose, due to development of tolerance, or needing to use more and more of the substance to obtain the desired effect. Withdrawal symptoms are equally dangerous: these are the uncomfortable and sometimes fatal physical symptoms that occur when the drug is absent from the body.


Substance abuse chart: This chart compares the relative danger of particular substances based on the dependence level developed and the potential physical harm to the user and others. Heroin, with an extremely high dependence and high potential for physical harm, is an extremely dangerous substance.

Substance abuse can have a variety of detrimental effects on the mind and body of the user.

Psychological Effects of Substance Abuse

Substance abuse can have a notable adverse effect on mood, increase the risk of mental illness, and exacerbate preexisting symptoms. Some people turn to substances to self-medicate for disorders like depression, anxiety, or bipolar disorder, only to find that substance use, while diminishing psychological distress in the short-term, only exacerbates the symptoms in the long run. Even worse is that the negative psychological side effects of substance use put abusers at a increased risk of suicide. Some substances can induce mood, anxiety, or psychotic symptoms, and these symptoms may persist even after the effects of the drug have subsided. In some cases hallucinogens like mescaline and peyote have triggered psychotic behaviors that last for years after use.

Physical Effects of Substance Abuse

In addition to adversely altering the mental health of users, substance abuse can have a significant and long-lasting impact on the body. Short term effects can manifest in the form of drowsiness and changes in breathing (slow breathing or hyperventilation), abdominal cramping, diarrhea, irregular heart rate, and even strokes. In the long term, users may suffer from dental and gum deterioration, sleep disorders, a variety of respiratory problems, and damage to the brain, kidneys, and liver. Users may also lose their appetite and their ability to regulate body temperature.

Substance abuse can also lead to secondary physical effects. A user's mental state may cause them to take unnecessary risks or engage in self harm or aggressive behavior toward others. Another array of secondary (physical) effects manifests if the user stops taking regular doses of the substance. This is often called "withdrawal" and can result in uncontrollable shaking and convulsions, extreme physical pain, and even dehydration, since users in this state may be unable to consume food and water. Yet another set of secondary effects stems from the unhealthy conditions in which substances are often consumed: for instance, sharing or using unsterilized needles can cause users to contract AIDS, hepatitis, or other diseases.


Spectrum of substance use: Substance use falls on a spectrum ranging from beneficial, prescribed and monitored use of prescription drugs to the recreational use, abuse, or dependence on illicit drugs.

Attitude and Health

Managing health requires understanding the influence of psychological factors (such as attitude and mood) and overall quality of life.

Learning Objectives

Examine the impacts of different attitudes and explanatory styles on health

Key Takeaways

Key Points

  • Part of health psychology is understanding how psychological factors (such as attitudes, beliefs, thoughts, moods, and emotions) and overall quality of life impact a person's health.
  • Psychological factors may impact our health directly, or they may influence our behaviors, which in turn affect our health in either positive or negative ways.
  • Both attitudes and moods (positive or negative) have important implications for health. The kind of attitude we hold about something influences our behavior and our experience of stress; interpreting an event in a negative way is a risk factor for a host of health problems.
  • Research indicates that optimism correlates with a lower likelihood of developing certain diseases. Learned helplessness and pessimism, on the other hand, are associated with depression, stress, weakened immune systems, and increased rates of minor and major ailments.
  • Health-related quality of life (HRQoL) is an assessment of how an individual's well-being may affect, or be affected by, a disease, disability, or disorder. Although causality cannot always be determined, poor quality of life is often correlated with poor health.
  • Health is negatively impacted by many aspects of quality of life, such as poverty, poor nutrition, lack of access to education, lack of leisure time, increased stress, and social isolation.

Key Terms

  • pessimistic explanatory style: A worldview in which people generally blame themselves for negative events, believe that such events will continue indefinitely, and let such events affect many aspects of their lives.
  • quality of life: The general well-being of individuals and societies, including not only wealth and employment, but also the built environment, physical and mental health, education, recreation and leisure time, and social belonging.
  • learned helplessness: The condition of a human or animal that has learned to behave helplessly, failing to respond even though there are opportunities for it to help itself by avoiding unpleasant circumstances or by gaining positive rewards.
  • optimism: A tendency to expect the best—or at least a potentially favorable—outcome.

The biopsychosocial model views health and illness as the product of a combination of biological factors (such as genes), psychological factors (such as behavior, lifestyle, stress, and health beliefs), and social conditions (such as cultural influences, family relationships, and social support). Certain behaviors such as diet, exercise, and substance use can influence our health. In this section, we will explore the influence of psychological factors and quality of life.

Part of health psychology is understanding how psychological factors (such as attitudes, beliefs, thoughts, moods, and emotions) and overall quality of life impact a person's health. "Quality of life" refers to the general well-being of individuals and societies, including not only wealth and employment (which are often referred to as "standard of living"), but also the built environment, physical and mental health, education, recreation and leisure time, and social belonging. These factors may impact our health directly, or they may influence our behaviors, which in turn affect our health in either positive or negative ways.

Psychology: Attitudes, Moods, and Our Health

One psychological factor that influences physical health is one's attitudes. An attitude can be thought of as a positive or negative evaluation of people, objects, event, or ideas.

Attitudes are changeable, they can be formed from a person's past and present, and they can influence a person's behavior and well-being. Some attitudes are explicit (i.e., deliberately formed) while others are implicit (i.e., unconscious or outside of awareness). Implicit and explicit attitudes both affect people's behavior, though in different ways. The kind of attitude we hold about a particular person, event, or idea influences how we behave in relation to it, and, thus, our experience of stress in relation to it. Stress is highly correlated with both physical and mental health, so if we hold a certain attitude toward something that increases our stress level, our health may suffer as a result.

Moods also have important implications for mental and physical health. Negative moods can influence people's behavior by determining how they interpret and translate the world around them. Interpreting an event in a negative way is a risk factor for a host of mental health problems including depression, anxiety, aggression, poor self-esteem, and physiological stress, all of which negatively impact one's health and well-being. Positive moods, on the other hand, are thought to increase the likelihood of physical health and well-being by lowering these risk factors.


Attitude and outlook: Research suggests that optimism and positive outlooks are associated with increased health and well-being, while pessimism and learned helplessness decrease health.

Learned Optimism vs. Learned Helplessness


Optimism is a world view that interprets situations and events as being optimal, or favorable. Learned optimism refers to the development of one's potential for this optimized outlook; it is the belief that one can influence the future in tangible and meaningful ways. Research shows that optimism correlates with physical health, including a lower likelihood of cardiovascular disease, stroke, depression, and cancer. It also correlates with emotional health, as optimists are more hopeful, have an increased sense of peace and well-being, and embrace change. Furthermore, optimists have been shown to live healthier lifestyles (i.e., smoking less, being more physically active, consuming healthier foods, and consuming more moderate amounts of alcohol) and utilize more positive coping mechanisms, both of which may lower the risk of disease.

Explanatory Style

Life or world outlooks have three general dimensions: internal vs. external, stable vs. unstable, and global vs. specific. In general, people with an optimistic outlook believe that negative experiences can be attributed to factors outside of the self (external), are not likely to occur consistently (unstable), and are limited to domains or circumstances (specific). They believe the exact opposite in regards to positive experiences, such that these are a result of the self (internal), expected to be repeated (stable), and broadly applicable to life (global). Optimists view the world as constantly working in their favor—even when physical or personal circumstances would seem otherwise. In this way, they are better equipped mentally to handle setbacks in everyday life, as these are believed to be momentary. They are also more likely to embrace and build upon positive circumstances and situations, as these are expected to continue.


In contrast, learned helplessness is the belief that one has no control over the events in one's life. Learned helplessness is associated with depression and anxiety, both of which threaten a person's physical and mental well-being; it can also contribute to poor health when people neglect diet, exercise, and medical treatment, falsely believing they have no power to change. The more people perceive events as uncontrollable, the more stress they experience, and the less hope they feel about making changes in their lives. Related to this, research has shown that people with a pessimistic explanatory style are more likely to suffer from depression and stress, have weakened immune systems, be more vulnerable to minor ailments (like a cold or fever) and major illnesses (such as heart attacks or cancer), and have a less effective recovery from health problems.

Quality of Life

Quality of life is recognized as an increasingly important healthcare topic. In general, quality of life is a person's assessment of their well-being, or lack thereof. This includes all emotional, social, and physical aspects of the individual's life. In healthcare, health-related quality of life is an assessment of how the individual's well-being may affect, or be affected by, a disease, disability, or disorder.

Internal Influences

An individual's perceived quality of life is often influenced by their personal expectations, which can vary over time based on environmental influences. Perceived quality of life is highly subjective, and patients' and physicians' rating of the same objective situation have been found to differ significantly. Patient questionnaires assessing quality of life are often multidimensional and cover physical, social, emotional, cognitive, work- or role-related, and possibly spiritual aspects, and even the financial impact of medical conditions. Although causality cannot always be determined, poor quality of life is often correlated with poor health, and high quality of life is often correlated with better health.

External Influences

Living conditions, nutrition, access to education, leisure time, and social isolation are all aspects of quality of life that have been shown to impact a person's health. Poverty is one aspect that is particularly significant—in fact, one third of deaths (around 18 million people a year) are due to poverty-related causes; in total 270 million people, most of them women and children, have died as a result of poverty since 1990. Those living in poverty lack access to basic resources such as healthcare, food, and housing, and suffer disproportionately from malnutrition, disease, lower life expectancy, and disability. Poverty has also been shown to directly impede cognitive function due to the severe burden on one's mental resources brought about by financial worries.


Poverty and health: Those living in poverty lack access to basic resources such as healthcare, food, and housing, and suffer disproportionately from malnutrition, disease, lower life expectancy, and disability.

Stages of Changing Unhealthy Behaviors

The transtheoretical model of behavior change, based on five stages of change, assesses a person's readiness to stop an old, unhealthy behavior and act on a new, healthy behavior.

Learning Objectives

Explain the stages of the transtheoretical model of behavior change

Key Takeaways

Key Points

  • Created by Prochaska and DiClemente in the 1970s, the transtheoretical model (also called the stages-of-change model) proposes that change is not a discrete decision, but is instead a five-step process that consists of precontemplation, contemplation, preparation, action, and maintenance.
  • At the precontemplation stage, an individual may or may not be aware of a problematic behavior, and generally has no desire to change their behavior.
  • At the contemplation stage, participants are intending to start the healthy behavior but are still ambivalent.
  • People at the preparation stage are ready to start taking action, and take small steps that they believe can help them make the healthy behavior a part of their lives.
  • In the action stage, people have changed their behavior and need to work hard to keep moving ahead. An individual finally enters the maintenance stage once they exhibit the new behavior consistently for over six months.
  • Despite the stress caused by their problem behavior, many people simply are not ready to initiate change; the stages-of-change model helps assess where on the spectrum they fall and to guide treatment efforts accordingly.

Key Terms

  • transtheoretical model: Also called the stages-of-change model; a model that describes behavior change as a process that involves a number of different stages.

The Process of Change

Because health psychology is interested in the psychology behind health-related behaviors, it also concerns itself with how people can learn to change their behaviors. The transtheoretical model of behavior change assesses an individual's readiness to act on a new healthier behavior, and provides strategies to guide the individual through each stage of the behavior-change process.

Created by Prochaska and DiClemente in the 1970s, the model proposes that change is a process rather than a discrete decision. People must build up the motivation to change and this motivation is dependent on a number of personal and environmental factors. According to the transtheoretical model, behavioral change is a five-step process, consisting of precontemplation, contemplation, preparation, action, and maintenance.


Stages-of-change model: The stages-of-change model explains behavior change as a process rather than a discrete decision.


At the precontemplation stage, an individual may or may not be aware of a problematic behavior, and generally has no desire to change their behavior. People in this stage learn more about healthy behavior: they are encouraged to think about the benefits of changing their behavior and to feel emotions about the effects of their negative behavior on others. Precontemplators typically underestimate the pros of changing and overestimate the cons. One of the most effective steps that others can help with at this stage is to encourage them to become more mindful of their decision making and more conscious of the multiple benefits of changing an unhealthy behavior.


At this stage, participants are intending to start the healthy behavior, often within the next six months. While they are usually more aware of the pros of changing, their cons are about equal to their pros. This ambivalence about changing can cause them to keep putting off taking action. People in this stage learn about the kind of people they could be if they changed their behavior and learn more from people who behave in healthy ways. Others can help people at this stage by encouraging them to work on reducing the cons of changing their behavior.


People at this stage are ready to start taking action, generally within the next 30 days. They take small steps that they believe can help them make the healthy behavior a part of their lives, such as telling their friends and family. People in this stage should be encouraged to seek support, tell people about their plan to change, and think about how they would feel if they behaved in a healthier way. Their main concern is this: When they act, will they fail? They learn that the better prepared they are, the more likely they are to keep progressing.


In the action stage, people have changed their behavior and need to work hard to keep moving ahead. These participants need to learn how to strengthen their commitments to change and to fight urges to slip back. Useful techniques at this stage can include substituting activities related to the unhealthy behavior with positive ones, rewarding themselves for taking steps toward changing, and avoiding people and situations that tempt them to behave in unhealthy ways.


An individual finally enters the maintenance stage once they exhibit the new behavior consistently for over six months. It is important for people in this stage to be aware of situations that may tempt them to slip back into doing the unhealthy behavior—particularly stressful situations. It is recommended that people in this stage seek support from and talk with people they trust, spend time with people who behave in healthy ways, and remember to engage in healthy activities to cope with stress instead of relying on unhealthy behavior.

Some theorists suggest a sixth phase called termination, in which individuals have no temptation to return to old unhealthy behaviors as a way of coping. Importantly, the progression through these stages is not strictly linear. People may move back and forth between the stages as their motivation changes. Often people relapse in their behavior multiple times before finally achieving maintenance. In this way, relapse is conceptualized as a return from the action or maintenance stage to an earlier stage.

Applying the Stages of Change

The stages-of-change model has been widely utilized in the treatment of health-related behaviors such as substance use, obesity, diabetes, and other problem behaviors. Change is a difficult process that requires close analysis of the benefits and costs of the behavior. For instance, a smoker must come to the conclusion that the health risks associated with their smoking are more important to them than the benefits, which may include taste, stress relief, social aspects, or other factors. Coming to this decision is no easy task; despite the stress caused by their problem behavior, many people simply are not ready to initiate change. This model helps assess where on the spectrum a person falls and helps guide treatment efforts accordingly.

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