Exercise and Your Health

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Exercise and Your Health

• Pennington Biomedical Research Center
• Division of Education

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First, well need to define some terms

• 1. Homeostasis This refers to the ability
  or tendency of an organism or cell to maintain
  internal equilibrium by adjusting its
  physiological processes. Once a weight loss or
  desired weight is achieved, this is what you
  want. This is what your body strives for at all
  times.
• 2. Energy Expenditure The act or process of
  using up energy. This is one component that must
  be considered when striving to achieve
  homeostasis.
• 3. Thermogenesis Generation or production
  of heat, especially by physiological processes.
  This is one of three components to energy
  expenditure.

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First, well need to define some terms

• 4. Basal Metabolism The minimal amount of
  energy required to maintain vital functions in an
  organism at complete rest. This is measured by
  the basal metabolic rate (BMR) in a fasting
  individual who is resting in a warm and
  comfortable environment.
• 5. Satiety The condition of being full or
  gratified beyond the point of satisfaction. Often
  times, we ignore this feeling or fail to notice
  it when eating.
• 6. Hunger Refers to a strong desire or
  need for food. It is the discomfort, weakness,
  or pain caused by a prolonged lack of food. It is
  not the same as appetite, or craving foods.

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Energy ExpenditureComponents

• Made up of three dominant components
• Basal metabolism
• Thermogenesis
• Physical activity
• Thermogenesis includes the dietary-induced and
  thermoregulatory components
• Only physical activity has a substantial element
  of voluntary control.

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Energy Intake

• Energy intake, on the other hand, is entirely
  voluntary, except in clinical conditions.
• Therefore, the modifiable aspects of the energy
  balance equation amount to just two variables
• Physical activity
• Food intake

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The Two Sides to Over Eating
Over Eating Driven by the agricultural revolution
Under Activity Driven by the technological
revolution
Inactivity, combined with overeating appear to be
the largest contributors to the
obesity epidemic. When energy intake (energy in)
and physical activity (energy burned) are at
balance with one another, the body is at
homeostasis. There is no weight loss,
and there is no weight gain. Weight is
simply maintained where it is.
This is the ideal situation,
provided the individual is at a healthy weight.
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Set Point Theory Body homeostasis

• Previous animal experiments indicate that there
  is a set point of body weight that is correctly
  defended under most conditions.
• Studies have demonstrated that there are natural
  feedback systems capable of regulating energy
  homeostasis with great precision in animals.
• The same is true for humans. The body wants there
  to be a balance between energy intake and
  expenditure.

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Overview of Energy Balance

• When energy intake is greater than energy
  expenditure, there is a net weight gain
• Energy intake gt Energy expenditure weight gain
• When energy intake is less than energy
  expenditure, there is a net weight loss
• Energy intake lt Energy Expenditure weight loss
• When energy intake and energy expenditure are at
  equilibrium with one another, weight is
  maintained
• Energy intake Energy Expenditure weight
  maintenance

The Energy Balance
Output
Intake
Calories Used During Physical Activity
Calories From Foods
To lose weight, an energy imbalance
eliciting an energy deficit is required.
This can be done through dieting,
exercising, or a combination of both.
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Set Point Theory Body homeostasis

• However, these feedback loops have been shown to
  only function appropriately within the settings
  in which they were originally developed. They
  have been shown to be easily disrupted by changes
  in the external environment, such as inactivity
  and the over consumption of energy-dense foods.
• In experimental animals, research shows that
  their ability to regulate energy balance was
  impaired once their movement was restricted and
  they were forced to become physically inactive.
• In addition, when their low-fat laboratory chow
  was replaced by a cafeteria diet with
  energy-dense and highly palatable foods, extreme
  obesity with massive fat deposition was the
  outcome.

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Set Point Theory Body homeostasis

• Similar outcomes have been noted in experiments
  involving humans where normal lean volunteers
  were asked to eat a diet prepared for them at the
  amount that they would normally consume per meal.
• These individuals were unaware that the fat
  content (and hence energy density) of the diets
  differed between each of the three dietary
  treatments.
• Energy balances were shown to be strongly
  influenced by the energy densities of the diets.
  This was believed to be due to a physiologic
  failure to recognize that the energy content of
  the diets differed and so, appetite or energy
  expenditure was not modified accordingly.

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ImbalancesPhysical Activity and Food Intake

• A survival imperative common to all mammals is
• The ability to maintain the bodys energy
  reserves in the form of hepatic (liver) and
  muscle glycogen, together with at least a limited
  supply of fat
• These energy reserves are necessary to support
  basic physiologic and immune functions, and to
  mount fight or flight responses.
• Because of these essential needs, hunger is
  believed to have evolved to be a strong
  physiologic drive made up by robust
  neuro-endocrine mechanisms, which are protected
  by multiple levels of redundancy.
• The same is true for humans.

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ImbalancesPhysical Activity and Food Intake

• Due to recurrent periods of food shortage and
  famine throughout time, it is believed that
  evolutionary pressures led to the ability for fat
  storage to well exceed that which is needed for
  day-to-day survival in humans.
• As a result, there has never been the imperative
  to develop strong satiety mechanisms.
• This imbalance between effectiveness of hunger
  and satiety signals is believed to lead to an
  asymmetry in appetite control. This could
  possibly explain why current lifestyles create
  such a high level of susceptibility to obesity in
  most individuals.

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ImbalancesPhysical Activity and Food Intake

• Because of this imbalance, many individuals have
  to learn to adopt cognitive dietary restraints in
  place of their natural physiologic regulatory
  system in order to maintain leanness.
• With the previous evidence in mind, this provides
  further support on the importance of exercise in
  aiding in body weight regulation.

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ImbalancesPhysical Activity and Food Intake

• Consequences of this asymmetry in appetite
  control are believed to be further confounded by
  marketing trends towards larger portion sizes and
  increased energy density of foods, each of which
  opposes the need of adapting a lower calorie
  intake in a progressively more sedentary world.

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The Importance of Exercise

• There are a number of published studies
  indicating that physical activity benefits stable
  weight maintenance, especially after a weight
  loss.
• The real benefit is not particularly during the
  weight loss itself, although it does contribute
  to the weight loss when combined with a dietary
  restriction, but more so in maintaining the
  weight loss once it is achieved.

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The Importance of Exercise

• The importance of exercise in aiding in weight
  maintenance is due to reasons discussed
  previously with respect to the asymmetry in
  appetite control, but is also due to the
  physiological effects of exercise in enhancing
  well-being and status of control, and hence
  compliance with a restrictive dietary regime.
• It is important to remember that there are many
  additional benefits of exercise. The benefits of
  exercise are not limited to just those previously
  discussed.

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The Importance of Exercise
It is beneficial in that it

• Reduces your risk of heart disease, high blood
  pressure, osteoporosis, diabetes, and obesity
• Reduces both total blood cholesterol and
  triglycerides and increases high-density
  lipoproteins, known as the good cholesterol.
• Reduces your risk for having a second heart
  attack
• Reduces your risk of developing colon cancer.
• Contributes to mental well-being and helps to
  treat depression
• Helps relieve stress and anxiety
• Increases your energy and endurance

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The Importance of Exercise
It is beneficial in that it

• Helps you maintain a normal weight by increasing
  your metabolism.(the rate in which your burn
  calories)
• Helps you sleep better.
• Keeps joints, tendons, and ligaments flexible so
  its easier to move around.
• Reduces some of the effects of aging.
• Helps older adults become stronger and better
  able to move about without falling or becoming
  excessively fatigued.

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Physical Activity Coronary Heart Disease

• A major, underlying risk factor for coronary
  heart disease is inactivity.
• In a study published in JAMA, men, who were
  initially unfit and became fit, were found to
  have a 52 lower age-adjusted risk of
  cardiovascular disease mortality than their peers
  who remained unfit.
• Regular physical activity has been shown to
  impact blood pressure beneficially.
• One study found that for every 26.3 men who
  walked more than 20 minutes to work, one case of
  hypertension would be prevented.

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Physical Activity Coronary Heart Disease

• It is important to note that these acute effects
  of exercise on blood pressure lowering do not
  require vigorous efforts. They can be achieved at
  40 of maximal capacity during exercise.
• Blood lipids play a major role in the development
  of atherosclerosis, which is the underlying cause
  of coronary heart disease.
• Moderate to vigorous-intensity aerobic exercise
  training has been shown to improve the blood
  lipid profiles of individuals.
• The most commonly observed changes have been
  increases in High density lipoprotein cholesterol
  (HDL), with reductions in total blood
  cholesterol, low-density lipoprotein cholesterol
  (LDL), and triglycerides.

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Physical Activity and Type 2 Diabetes

• Physical activity is associated with
• A reduced risk of type 2 diabetes
• Improved insulin sensitivity
• Glucose homeostasis
• From participating in physical activity 30
  minutes/day, overweight subjects were able to
  reduce their risk of getting type 2 diabetes by
  58 in a recent study.
• Physical inactivity has been shown to elevate the
  risk of developing type 2 diabetes in
  normal-weight individuals as well.

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Physical Activity Overweight/Obesity

• Physical activity appears to be an important
  component in weight stability for healthy
  individuals.
• In a recent study looking at the effects of
  physical activity on body composition in 3,853
  healthy subjects between the ages of 15 and 64,
  it was concluded that physical activity is able
  to limit both fat mass and weight gain in men and
  women.
• Many studies are in agreement with one another
  when stating that exercise diet lead to greater
  weight losses than just diet-alone.
• In a review of 11 studies looking at the
  influence of both exercise and diet on weight
  loss, the average weight loss of the diet-only
  group was shown to be 6.7 kg whereas, the
  average weight loss of the diet exercise group
  was 8.5 kg.

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Physical Activity Overweight/Obesity

• Weight loss is not only achieved, but is also
  maintained through physical activity.
• In 2001, a study was conducted on 3000 previously
  obese subjects, who reported a weight loss of 30
  kg, on average, which was additionally maintained
  for an average of 5.5 years.
• When looking at those who did not continue to
  participate in physical activity, it was found
  that only 9 of these participants were able to
  maintain their weight loss in the absence of
  physical activity.

This further supports the importance of exercise
in the prevention of weight regain.
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Physical Activity Overweight/Obesity

• The optimal amount of weekly exercise necessary
  to prevent weight gain is still a topic under
  much debate.
• The current recommendations include, at a
  minimum, 150 minutes/wk of moderate-intensity
  exercise, or 30 minutes a day on most days of
  the week (5 or more).
• This should be the initial targeted amount of
  exercise each week

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Physical Activity and Appetite Control

• Physical activity has the potential to adjust
  appetite control by
• Improving the sensitivity of the physiological
  satiety signaling system
• Adjusting macronutrient preferences or food
  choices
• Altering the hedonic (pleasurable) response to
  food
• There exists a belief that physical activity
  drives up hunger and increases food intake,
  thereby rendering it useless as a means of weight
  control.
• In a recent study, researchers set out to examine
  this very idea.

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Physical Activity and Appetite Control
Recent Findings

• Short term (1-2 day) and medium term (7-16 day)
  studies demonstrated that men and women can
  tolerate substantial negative energy balances
  when performing physical activity programs.
• The immediate effect of taking up exercise is
  weight loss.
• This isn't always easy to assess however, due to
  changes in body composition or fluid
  compartmentalization that arise.
• Once around 30 of energy is expended in
  activity, food intake then begins to increase in
  order to provide compensation for this loss.
• This compensation (up to 16 days) is partial and
  incomplete.

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Physical Activity and Appetite Control
Recent Findings

• Subjects have been separated into compensator and
  non-compensator groups.
• The exact nature of the differences noted in
  these 2 groups has yet to be determined.
• Some subjects performing a set routine of
  activities for a 14 day period showed no
  differences in energy intake.
• More studies are needed to further classify
  individuals who are compensators versus
  non-compensators and to identify the mechanisms
  responsible for the rates of compensation and its
  limits.

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Physical Activity and Osteopenia

• Everyday physical activity has a positive effect
  on skeletal mass.
• It has been suggested that electrical currents
  are developed when bone is mechanically stressed,
  leading to the formation of new bone.
• When comparing whole body, leg, and trunk body
  mineral densities in women who walk 7.5
  miles/week versus those who walk 1 mile per week
  or less, women in the group with the most
  distance were shown to have significant increases
  in bone density.

Normal bone Osteoporotic bone
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Physical Activity and Sarcopenia

• Sarcopenia can be defined as the age-related loss
  of muscle mass, strength, and function.
• Physically active subjects aged over 65 years
  have a significantly higher level of lean tissue
  mass than sedentary participants.
• It has also been shown that healthy older people
  can safely tolerate higher intensity strength
  training with improvements comparable with those
  seen in younger persons.

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Physical Activity Psychological Disorders

• Physical activity is associated with elevations
  in mood states and heightened psychological
  well-being.
• On the other hand, inactive persons have been
  shown to be 1.5 times more likely to become
  depressed than those who maintain an active
  lifestyle.
• Physical activity is believed to be protective
  against the development of Alzheimers disease.
• This is believed to be due to increased blood
  flow, which may in turn promote nerve cell
  growth.
• It has been suggested that people who are
  intellectually and physically inactive have a
  250 better risk of developing the disease.

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The Truth on Exercise

• The bad news is that people still are not getting
  enough exercise.
• This map specifically looks at physical activity
  trends in women and finds that only 4 in 10 women
  are engaging in the recommended levels of
  activity.
• Activity has been shown to generally decrease
  with age, and is less common among women than in
  men and among those with lower income and less
  education.

Source CDC. Behavioral Risk Factor Surveillance
System, 2001. Photo from http//womenshealth.gov

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Inactivity

• Inactivity leads to a loss of muscle, to obesity,
  and to reduced functional ability.
• Low physical fitness increases the risk for
  cardiovascular disease, diabetes, and some
  cancers.
• Individuals who are physically fit can do more
  things, have better endurance for activities and
  tasks, and are healthier than individuals with
  low fitness.
• Even small increases in physical activity can
  make a big difference to an individuals health.
• Try to incorporate small changes into your daily
  activities. This, in time, will gradually improve
  your fitness, leading to a better you.

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Physical Activity and Physical Fitness
Whats the difference?

• Physical activity is defined as any bodily
  movement produced by skeletal muscles that
  results in an expenditure of energy.
• Exercise is defined as a subset of physical
  activity that is planned, structured, repetitive,
  and purposeful.
• Physical fitness is a measure of ones ability to
  perform physical activities that require
  endurance, strength, or flexibility, and is
  determined by a combination of regular activity
  and genetically inherited ability.
• Simply put, fitness is good, but physical
  activity is a must!

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Types of Exercise
Aerobic, anaerobic, and resistance

• Aerobic exercise is exercise that involves large
  muscle groups (arms and legs) in dynamic
  activities that result in substantial increases
  in heart rate and energy expenditure.
• Anaerobic exercise is exercise done at very high
  intensities such that a large portion of the
  energy is provided by glycolysis and stored
  phosphocreatine. These activities build and tone
  muscles, but are not as beneficial to the heart
  and lungs as aerobic activities are.
• Resistance exercise is exercise designed
  specifically to increase muscular strength,
  power, and endurance by varying the resistance,
  the number of time the resistance is moved in a
  single group (set) of exercise, the number of
  sets done, and the rest interval provided between
  sets.

Anaerobic
Aerobic
Resistance
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Examples

• Anaerobic
• Baseball
• Sprinting
• Tennis
• Weightlifting
• Leg lifts
• Arm circles
• Curl-ups
• Dusting
• Doing laundry
• Washing windows

• Aerobic
• Brisk walking
• Dancing
• Jogging
• Bicycling
• Skating
• Swimming
• Snow shoveling
• Lawn mowing
• Leaf raking
• Vacuuming

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Physical Activity for Everyone

• Everyone can benefit in some way by regular
  physical activity. Whether you are trying to
  maintain a weight loss or just feel more
  energetic when you incorporate exercise into your
  daily activities. There are also the benefits
  later in life from exercising. These include
  reductions in the risk of developing chronic
  diseases and overall improvements in your quality
  of life.

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Who Benefits and How?

• Older adults No one is too old to enjoy the
  benefits from regular physical activity. Evidence
  indicates that muscle-strengthening exercises can
  work to reduce the risk of falling and fracturing
  bones, and can improve the ability to live
  independently.
• Parents and children Parents can help their
  children maintain a physically active lifestyle
  by providing them with encouragement and
  opportunities for exercise. Outings and family
  events are encouraged, particularly when everyone
  in the family is involved.

Centers for Disease Control
and Prevention (CDC)
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Who Benefits and How?

• Teenagers Regular physical activity improves
  strength, builds lean muscle, and decreases body
  fat. Activity can build stronger bones to last a
  lifetime.
• People trying to manage their weight
  Regular physical activity
  helps to burn calories while preserving lean
  muscle mass. Regular physical activity is an
  important component to any weight-loss or
  weight-maintenance activity.
• People with high blood pressure
  Regular physical activity
  helps to lower blood pressure.

Centers for Disease Control
and Prevention (CDC)
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Who Benefits and How?

• People with physical disabilities, including
  arthritis
• Regular physical activity for individuals
  with chronic, disabling conditions is important
  because it can help improve their stamina and
  muscle strength. It can also improve the quality
  of life by improving the individuals ability to
  perform daily activities.
• Everyone under stress, including persons
  experiencing anxiety or depression
• Regular physical activity has been shown
  to improve ones mood, help relieve depression,
  and increase feelings of well-being.

Centers for Disease Control
and Prevention (CDC)
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Getting Started

• You will first want to begin by speaking with
  your doctor.
• This is particularly important if you
• Are elderly
• Currently smoke
• Have any health problems
• Are overweight or obese
• Have not been active in a while
• Are currently pregnant
• Are unsure of your health status
• Feel pain in your chest, joints or muscles during
  activity
• When it is okay to begin, you want to start out
  slowly. A good suggestion could be to begin with
  a 10-minute period of light exercise or a brisk
  walk every day. You can then gradually increase
  how hard you exercise for and how long.

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Ways to Improve Your Health

• Walking or jogging
• Swimming
• Bicycle riding
• Group exercises
• Weight-bearing exercise, such as weight lifting,
  resistance bands, or activities involving the
  whole body
• Stretching, such as yoga or tai chi exercises
• Participation in active sports, such as tennis,
  basketball, and soccer

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Ways to Add Activity to Your Day

• Park the car in the furthest spot from the
  entrance and walk the extra distance
• Get off of the bus one stop before your
  destination and walk
• Take the stairs instead of the elevator
• Take walking breaks during the work day
• Take a 10-minute walk during your lunch break
• Walk a dog or play outside with the kids
• Dance to your favorite music
• Use housecleaning as an exercise opportunity
• Ask a friend, family member, or coworker to walk
  with you

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Physical Activity Calorie Use Chart
Activity 100 lb 150 lb 200 lb
Bicycling, 6 mph 160 240 312
Bicycling, 12 mph 270 410 534
Jogging, 7 mph 610 920 1230
Jumping rope 500 750 1000
Running, 5.5 mph 440 660 962
Running, 10 mph 850 1280 1664
Swimming, 25 yds/min 185 275 358
Swimming, 50 yds/min 325 500 650
Tennis singles 265 400 535
Walking, 2 mph 160 240 312
Walking, 3 mph 210 320 416
Walking, 4.5 mph 295 440 572
The chart shows the approximate calories spent
per hour by a 100, 150 and 200 pound person doing
a particular activity
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Adults should strive to meet either of the
following physical activity recommendations

• Adults should engage in moderate-intensity
  physical activities for at least 30 minutes on 5
  or more days of the week (CDC/American College of
  Sports Medicine). This 30 minutes per day can be
  accumulated in bouts of 10 minutes throughout the
  day.
• Adults should engage in vigorous-intensity
  physical activity 3 or more days per week for 20
  or more minutes per occasion (Healthy People
  2010)

Tip
While activity at a higher intensity or performed
longer does offer more
health benefits, this level of activity may not
be a realistic goal for everyone,
at least not to start with. Again, work your
way to this, slowly,
by setting realistic goals for each
week.
Or
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Moderate Intensity Activity
Whats is it?

• This is an activity which generally causes a
  slight, but noticeable increase in breathing and
  heart rate. It may also cause light sweating.
• Some examples of moderate intensity activity
  include
• Brisk walking
• Swimming
• Cycling
• Dancing
• Doubles Tennis

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Sites

• Exercise A Healthy Habit to Start and Keep.
  Available at http//www.familydoctor.org
• Exercise When to check with your doctor first.
  Available at http//www.mayoclinic.com/print/exer
  cise/SM00059/METHODprint
• Physical Activity. Available at
  http//womenshealth.gov/pub/steps/Physical20Activ
  ity.htm
• Physical Activity Calorie Use Chart. Available
  at http//www.americanheart.org/presenter.jhtml?i
  dentifier756
• The Journal of the American Medical Association
  (JAMA). Available at http//www.jama.com
• Physical Activity for Everyone The Importance of
  Physical activity. Available at
  http//www.cdc.gov/nccdphp/dnpa/physical/importanc
  e/index.htm
• General Physical Activities Defined By Level of
  Intensity. Available at http//www.cdc.gov/nccdph
  p/dnpa/physical/pdf/PA_Intensity_table_2_1.pdf
• Sarcopenia The Mystery of Muscle Loss. Available
  at http//www.unm.edu/lkravitz/Article20folder/
  sarcopenia.html
• Physical Activity and Weight Control. Available
  at http//win.niddk.nih.gov/publications/physical
  .htm
• Aerobic or Anaerobic? Quick Activity. Available
  at http//www.americanheart.org/presenter.jhtml?i
  dentifier3003065

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Sites

• Melzer K, Kayser B, Pichard C. Physical activity
  the health benefits outweigh the risks. Current
  Opinion in Clinical Nutrition and Metabolic Care.
  2004 7 641-47.
• Prentice A, Jebb S. Energy intake/physical
  activity interactions in the homeostasis of body
  weight regulation. Nutrition Reviews. 2004
  62(7) S98-S104.
• Blundell JE, Stubbs RJ, Hughes DA, Whybrow S,
  King NA. Cross talk between physical activity and
  appetite control does physical activity
  stimulate appetite? Proceedings of the Nutrition
  Society. 2003 62 651-661.
• Moore M. Interactions between physical activity
  and diet in the regulation of body weight.
  Proceedings of the Nutrition Society. 2000 59
  193-198.
• Jakicic J, Otto A. Physical activity
  considerations for the treatment and prevention
  of obesity. Am J Clin Nutr. 2005 32(suppl)
  226S-9S.

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About Our Company

• The Pennington Biomedical Research Center is a
  world-renowned nutrition research center.
•  
• Mission
• To promote healthier lives through research and
  education in nutrition and preventive medicine.
•  
• The Pennington Center has several research areas,
  including
•  
• Clinical Obesity Research
• Experimental Obesity
• Functional Foods
• Health and Performance Enhancement
• Nutrition and Chronic Diseases
• Nutrition and the Brain
• Dementia, Alzheimers and healthy aging
• Diet, exercise, weight loss and weight loss
  maintenance
•  
• The research fostered in these areas can have a
  profound impact on healthy living and on the
  prevention of common chronic diseases, such as
  heart disease, cancer, diabetes, hypertension and
  osteoporosis.
•  
• The Division of Education provides education and
  information to the scientific community and the
  public about research findings, training programs
  and research areas, and coordinates educational
  events for the public on various health issues.