Homeostasis and Physical Fitness

• "Service organs" challenge homeostasis through feedback adjustment
• Allostasis facilitates energy according to the environment through feedforward adjustment

Physical Activity (PA) Levels

• Light PA uses less than 150 calories per day, e.g., walking to work, taking stairs, household chores
• Moderate PA uses 150-1000 calories per week, e.g., brisk walking, cycling, raking leaves
• Vigorous PA requires 6+ METs energy per day, e.g., sports/exercise

Fitness Types

• Health-related fitness involves abilities to perform daily activities without undue fatigue, including cardiorespiratory endurance, muscular fitness, muscular flexibility, and body composition
• Skill-related fitness includes components important for success in skillful activities and athletic events, such as agility, balance, coordination, reaction time, speed, and power - Required for general health promotion and wellness
• Musculoskeletal fitness testing assesses strength, endurance, and power then compares results to normative values for age and gender
• Muscle strength measures the maximum amount of force produced
• Muscle endurance measures the ability to perform repetitive contractions for prolonged periods of time (fatigue resistance)
• Muscle power measures the ability to contract/explode with speed and force, important for functional capacity
• Other ways to measure strength are 1RM and 10RM tests
• Aerobic fitness testing includes the VO2max test (gold standard), submaximal aerobic tests, and field-based tests (Leger)

Fitness and Wellness

• Non-exercise activity thermogenesis (NEAT) covers energy expenditure doing everyday activities not related to exercise
• Health and longevity are determined by environment, behavior, and genetics

Mortality and Disease

• Infectious diseases were the primary cause of death in the 20th century, with a life expectancy of 47 years
• There is a shift from infectious diseases to chronic diseases in the medical field
• Cardiovascular disease is the highest cause of death in the USA, followed by cancer

Sitting Disease

• Sitting for 4+ hours a day is unnatural and hazardous, linked to premature mortality
• It increases the risk of metabolic problems like insulin sensitivity and increased abdominal fat, even for those who exercise
• The solution is to stand and move every 30 minutes and take intermittent 5-minute breaks every half hour

Sedentary Death Syndrome (SeDS) and Hypokinetic Diseases

• Sedentary Death Syndrome involves causes of death related to lack of regular physical activity, hastening deterioration
• Hypokinetic diseases are illnesses related to lack of physical activity (hypo=less, kinetic=movement)

Physical Activity and Health Benefits

• Greater health benefits come with higher intensity of PA
• There is an inverse relationship between physical activity (PA)/premature mortality rates
• Exercise is more effective than drugs on health outcomes
• Exercise is medicine initiative involves exercise prescriptions for patients

Physical Activity Recommendations

• Modern intensity physical activity (MIPA) recommends 150 minutes of exercise time
• Vigorous intensity physical activity (VIPA) recommends 75 minutes of exercise time
• If worldwide inactivity reduces by 20%, 1 million lives will be saved every year

Exercise Training (ET)

• Long-term ET (4-5 days a week, 30 minutes) maintains "youthful" left ventricular compliance and distensibility, reduces central arterial stiffness and blood pressure
• 170-242 minutes/week of self-perceived moderate ET or 90-128 minutes/week of vigorous ET reduces CVD risk by 69%
• Higher levels of reported exercise MAY show a U-shaped curve relationship between exercise and cardiovascular disease (CVD)
• A U-shaped curve can also be seen in high-volume/high-intensity long-term exercise training, potentially leading to adverse cardiovascular complications

Potential Exercise Complications

• Accelerated coronary artery calcification (calcium buildup in artery walls)
• Myocardial fibrosis (increase in collagen volume of myocardial tissue)
• Atrial fibrillation (irregular heart rhythm/arrhythmia due to electrical signal disturbance of heart)
• Higher risk of sudden cardiac death

Functional Capacity and Exercise Benefits

• Regular physical activity benefits muscle, bone, and joint health, as well as mood, cognitive functions, and creativity
• Exercise increases blood flow to the brain, facilitates removal of metabolites, and prevents the development of plaques and dementia/Alzheimer's
• Exercise allows the release of brain-derived neurotrophic factor (BDNF), strengthening connections between brain cells
• Exercise increases dopamine, glutamates, norepinephrine, serotonin, and association between physical fitness and academic achievements

Behavioral Influences

• External obstacles (Physical/Social) that promote unhealthy practices and social norms are called anchor points- family traditions, media representation, public health guidelines
• ANCHOR POINTS are social norms individuals use as a reference when considering a new behavior
• Environmental factors influence physical activity (PA) and diet/nutrition

Environment and Lifestyle

• Work/leisure time involves increased sedentary jobs and screen time
• Community design means modern lifestyles involves hours spent sitting in cars
• Schools/community results in less PA and insurance plans

Food Policy and Habits

• A surplus of 500 calories a day per person is common
• Dining out involves larger portions and higher caloric content for a small price (marketing)
• Restaurants are designed to enhance comfort and appetite

Changing Behavior

• Values are core beliefs and ideals that govern behavior with educational experiences which help establish these values and shaped by examples/role models
• Unique individuality and nature impact goal setting, creating a linear relationship of confidence and motivation
• Brain areas (basal ganglia) where habits are formed (automatic) are affected by dopamine (key in formation) and striatum (motor control)
• Habits involve brain functions, familiar cues, saving energy, important in times of stress
• Prefrontal cortex (PFC) changes habits by focusing on long-term values, overriding instant rewards in exchange for long-term gratification, putting a brake on impulsive behavior (Serotonin is abundant in PFC)

Locus of Control and Barriers

• Internal Locus of Control means you have control over your life
• External Locus of Control means what happens is due to change, environment, unrelated to oneself
• Barriers to change involve a lack of core values, complexity, procrastination, preconditioned cultural beliefs, gratification, risk complacency, indifference/helplessness, rationalization, illusion of invincibility, overplanning, loss aversion
• Behavior change learning theories (increased knowledge of obesity) and problem-solving models (reducing BP)

Theories on Change

• Social cognitive theory involves family/friends in the process
• Relapse prevention model is for avoiding hospitalization
• Humanistic theory of change

Transtheoretical Model of Change

• There are 6 stages in the Transtheoretical Model
• Stages include: precontemplation, contemplation, preparation, action, maintenance, termination or adoption
• Relapse can occur at any stage

SMART Goals

• Acronym to help make goals: Specific, Measurable, Acceptable, Realistic, Time-specific

Body Composition

• Body composition is not dependent on body weight
• It determines risk for premature illness/death and identifies weight-related and lifestyle changes

Body Composition Models

• Two-component model involves whole body = fat + fat-free body component, with FFB density depending on age, sex, ethnicity, PA BF%
• It assumes Density of fat = 0.901 g•cc −1 and Density of FFB = 1.10 g•cc-1
• It assumes the Densities of the various tissues composing the FFB are constant within an individual, and Densities of fat and FFB components are the same for everyone as well as Individuals are measured compared to the reference body only in the amount of body fat
• Multi component model attempts eliminate systematic error of estimation in 2 component model assumptions

Measurements and Standards

• Measure % of water and % mineral
• Utilizes the reference method for developing population-specific reference and formulas
• Factors in age, sex, ethnicity
• Population-specific prediction equations do not exist for all age groups within ethnicities

Obesity and Body Mass Index (BMI)

• Obesity involves an excessive amount of fat related to body weight
• BMI = kg/height m^2
• Obesity means BMI is > 30 kg/m^2
• Overweight means BMI is 25-29.9 kg/m^2
• Underweight means BMI is < 18.5 kg/m^2

Fat Distribution

• Android fat is stored in the trunk/abdominal area
• Gynoid fat is stored around hips/thighs
• Essential fat is needed for normal physiological function
• Storage fat is stored in adipose tissue (subcutaneous/visceral fat), stores needed calories, releases hormones that control metabolism, retains body heat and acts as padding against physical trauma

Fat Types

• Subcutaneous fat is fat stored directly under the skin, assists in releasing beneficial hormones, suppressing appetite, burning stored fat, and increases insulin sensitivity
• Visceral fat is fat stored around internal organs, metabolizes into fatty acids more readily than subcutaneous fat, and has a greater risk of diseases than subcutaneous fat

Techniques in Assessing Body Composition

• Skinfold thickness, girth, bioelectrical impedance, dual energy x ray, hydrostatic weighing, air displacement
• Only important ones in table*

Skinfold Thickness (SKF)

• Skinfold Thickness is an indirect measurement of subcutaneous body fat % using assumptions from 2 component model

SKF Assumptions

• SKF is a good measure of subcutaneous fat
• Distribution of subcutaneous and internal fat is similar for all sexes
• The Sum of SKDs from multiple sites is used to estimate total body fat
• More fat in abdominal fat, little fat in thigh area

Bioelectrical Impedance Analysis (BIA)

• Bioelectrical Impedance Analysis is a non-invasive - indirect method of measuring FFM (fat-free mass)
• Sensors applied to the skin and a weak electrical current is run through the body to measure its electrical resistance
• Fat tissue is a less efficient conductor than lean tissue
• Combination of pairs of sending and receiving electrodes with low-level electrical currents passed between electrode pairs
• Tissues either interfere (impede) or conduct electrical currents
• Total body water (TBW) volume inversely related to resistance of currents

Dual-energy X-Ray Absorptiometry (DXA)

• It is a 3 component model
• It uses dual x-ray beam frequencies which are safe/fast, low radiation exposure
• Attenuation of x-rays through fat, lean tissue/bone varies bc of diff densities and chemicals
• Requires fasting prior to DXA for best testing accuracy and minimal client effort and participation
• It is NOT recommended for pregnant women due to radiation
• DXA is the Gold standard for visceral adipose tissue assessment
• Best method to estimate mineral contribution to FFB