ACSMCDC Physical Activity Recommendations2007 Naval Occupational Health

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ACSM/CDC Physical Activity Recommendations2007Na
val Occupational Health Preventive Medicine
ConferenceMarch 19, 2008Hampton Roads, VA

• Steven N. Blair
• Professor of Exercise Science
  Epidemiology/Biostatistics
• University of South Carolina
• Executive Lecturer, Kinesiology, Health
  Promotion, and Recreation
• University of North Texas

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Outline

• Early research on physical activity, fitness, and
  health
• History of physical activity recommendations
• Exercise prescription model
• New recommendations in the 1990s
• Research and recommendations following the U.S.
  Surgeon Generals Report on Physical Activity and
  Health
• ACSM/AHA recommendations2007
• Physical Activity Guidelines2008

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Physical Activity and Health

• J. Morris (mid-1950s to present)
• First systematic evaluation of the effects of
  inactivity on CHD
• London busmen
• British Civil Servants
• R. Paffenbarger (early-1960s to 2007)
• San Francisco longshoremen
• College Alumni studies
• Physical inactivity is now accepted as a cause of
  early morbidity and mortality
• AHA, ACSM/CDC, Surgeon General, NIH, WHO/FIMS

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Exercise Training

• M. Karvonnen (mid-1950s)
• One of the first systematic experimental studies
  on the physiological effects of exercise training
• Specifically investigated the role of exercise
  intensity (led to the Karvonnen equation)
• Many investigators (1960s to present)
• Developed the knowledge base for the ACSM
  exercise prescription
• Quantity and quality of exercise ACSM position
  stands--1978, 1990, 1998
• Investigations continue on intensity,
  accumulation of dose, genetic influences, other
  variables

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Physical Activity Interventions

• Very new area of research in exercise science
• Little work done before 1980
• Stanford HDPP, J J, L. Epstein
• Basic approach is to bring technologies and
  methods developed by behavioral scientists for
  other applications into exercise science
• Example--smoking cessation intervention in the
  MRFIT in the early 1970s
• Social Learning Theory, Stages of Change
• In the past decade many investigators are
  conducting physical activity interventions--J.
  Sallis, A. King, A. Dunn, B. Marcus, J. Martin,
  P. Dubbert, R. Wing, J. Jakicic, B. Cardinal, R.
  Andersen, T. Robinson

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Karvonens Classic Study

• 6 male medical students, 20-23 years of age
• Treadmill running at 0 grade
• Trained 4-5 days/week, 30 minutes/day
• 4-week training period
• Primary outcomerunning speed at a predetermined
  heart rate

Karvonen MJ et al. Ann Med Exp Fenn 1957
35307-15
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KarvonenSubjects and Training Parameters
Karvonen MJ et al. Ann Med Exp Fenn 1957
35307-15
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Karvonen--Results
Karvonen MJ et al. Ann Med Exp Fenn 1957
35307-15
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Exercise Intensity Training Studies

• Typical conclusionHigh intensity exercise is
  required to improve aerobic power.
• More appropriate conclusionHigher intensity
  exercise causes greater improvement in aerobic
  power over the short-term than does moderate
  intensity exercise, at least in young, healthy,
  and relatively fit men.

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Limitations of Exercise Training Studies on
Intensity

• Young (healthy and fit?) men
• Woefully underpowered
• Short-term training
• Incomplete statistical comparisons
• Sometimes had no control group
• Asked Did higher intensity groups improve more
  than lower intensity groups? rather than Did
  lower intensity groups improve.

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Early Studies on Quantification of Exercise Dose

• Several studies in the 1960s and 1970s on
  exercise intensity
• All studies had young men as participants
• All were relatively short-term
• All showed that higher intensity exercise group
  made greater improvement than lower intensity
  group
• All lower intensity groups made improvement from
  baseline

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Background Public Health Recommendations for
Physical Activity1990s

• Landmark recommendation was the 1992 AHA
  statement on exercise in which inactivity was
  named the 4th risk factor for coronary artery
  disease
• Led to an AHA Committee on Strategic Planning for
  Exercise
• NIH Consensus Development Conference
• Surgeon Generals Report on Physical Activity
• National Coalition for Promoting Physical
  Activity
• Research training seminar

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CDC/ACSM Physical Activity RecommendationsPate
RR et al. JAMA 1995

• Every US adult should accumulate 30 minutes or
  more of moderate-intensity physical activity on
  most, preferably all, days of the week.
• Moderate-intensity - Activity performed at 3 to 6
  times the resting metabolic rate.
• Equivalent to brisk walking 2 miles at 3 to 4 mph
  (15 to 20 minutes/mile) for healthy adults

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Consensus Public Health Recommendation for
Physical Activity

• Statements from the American College of Sports
  Medicine/Centers for Disease Control and
  Prevention, American Heart Association, NIH, the
  US Surgeon General, and U.S. Dietary Guidelines
  2005 conclude
• All adults should accumulate at least 30 minutes
  of at least moderate intensity physical activity
  each day
• This is equivalent to walking about 1.5 miles at
  a pace of 3 to 4 mph
• Doing more exercise and perhaps more strenuous
  exercise may produce additional health benefits
• Resistance exercise provides health benefits

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Physical Activity RecommendationsSurgeon
Generals Report to the Present
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Health Effects of Moderate Physical Activity

• What is moderate physical activity?
• Moderate amounts of activity
• Moderate intensities of activity
• Exercise training studies
• Precise control of amount and intensity
• Outcomes--aerobic power, blood pressure, lipids,
  body composition

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Asikainen T-M et al. Randomized, controlled
walking trials in post menopausal women the
minimum dose to improve aerobic fitness. Br J
Sports Med 2002 36189-194.
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Methods

• Design--RCT with control and 4 walking groups
• W1--55 and 1500 kcal/week
• W2--45 and 1500 kcal/week
• W3--55 and 1000 kcal/week
• W4--44 and 1000 kcal/week
• Participants--women, 2-10 yr past menopause,
  48-63 yr of age, no chronic diseases, no regular
  medication use, non-smoker, BMI lt 32, resting BP,
  lt160/90, sedentary, continue previous diet and PA

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Methods

• Exercise program
• 5 days per week--2 days at UKK center, 3 days on
  their own
• 24 weeks duration
• Walking
• Exercise intensity--THR from baseline exercise
  test
• Daily exercise recorded in diaries and recorded
  by pedometers for 3 days in the middle of the
  trial
• Primary outcome--change in VO2 max

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Adherence

• 121 women were randomized into the trial
• 3 of the 81 exercisers dropped out
• 5 of the 121 did not complete follow-up testing
• Total walked (km/week)
• W18.7
• W28.3
• W37.0
• W47.1
• No changes in diet during study

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Change in VO2 Max, at 24 Weeks, by Walking Groups
? VO2 max
1500 kcal/week
1000 kcal/week
55 of VO2 max
Asikainen et al. Br J Sports Med 2002 36189-94
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Summary

• Walking at moderate intensities and moderate
  exercise doses improved aerobic power in
  sedentary, postmenopausal women
• There was little difference in improvement in
  aerobic power by intensity or weekly walking dose

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Asikainen T-M et al. Walking trials in
postmenopausal women effect of one vs two daily
bouts on aerobic fitness. Scand J Med Sci Sports
2002 1299-105
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Methods

• RCT with 3 parallel groups
• I one exercise session/day
• II two exercise sessions/day, separated by at
  least 5 hours
• Control
• Exercise frequency--5 days/week
• Exercise intensity--65 of V02 max
• Weekly dose--1500 kcal
• Exercise modality--walking
• Duration of study--15 weeks

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Methods

• 2 sessions/week supervised at UKK center
• HR monitors used for all supervised sessions and
  every third week for all sesssions
• Participants--women, 2-10 yr past menopause,
  48-63 yr of age, no chronic diseases, no regular
  medication use, non-smoker, BMI lt 32, resting BP,
  lt160/90, sedentary, continue previous diet and
  PA, equal numbers on and not on HRT
• Primary outcomes--aerobic power, HR response to
  submaximal exercise, and body composition

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Adherence

• 134 women were randomized
• 131 women completed the 15-week assessment
• 3 of 88 exercising women interrupted training
  because of injuries
• Group I women attended 89 of the prescribed
  sessions
• Group II women attended 95 of the prescribed
  sessions

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Results
?VO2 max
p lt0.001
Asikainen T-M. Scand J Med Sci Sports 2002
1299-105
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Summary and Conclusion

• Changes in aerobic power and body composition
  were comparable in one or two exercise sessions
  per day at a dose of 1500 kcal/week
• Current public health recommendations for
  physical activity are supported by the results of
  this study

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Physiological Effects of Moderate Physical
Activity in Experimental Trials

• There are numerous recent randomized or
  controlled clinical trials of exercise with
  physiological adaptations as outcomes
• Essentially all of these studies show
  improvements in variables such as insulin
  sensitivity, blood pressure, body composition,
  and aerobic power with moderate amounts and
  intensities of activity
• Moderate amount8 kcal/kg/week
• Moderate intensity40-60 aerobic power

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Institute of Medicine Report on Dietary Reference
Intakes
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IOM Report on Dietary Reference Intakes, 2002,
Chapter 12Physical Activity

• Physical activity and exercise promote health
  and vigor. As identified previously by other
  groups (DHHS, 1996), some benefits can be
  achieved with a minimum of 30 minutes of moderate
  intensity physical activity most days of the
  week. However, 30 minutes per day of regular
  activity is insufficient to maintain body weight
  in adults in the recommended body mass index
  range of 18.5 up to 25 kg/m2 and achieve all the
  identified health benefits fully.

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PA Recommendations-U.S. Dietary Guidelines--2005

• Engage in regular physical activity and reduce
  sedentary activities to promote health,
  psychological well-being, and a healthy body
  weight.
• To reduce the risk of chronic disease in
  adulthood Engage in at least 30 minutes of
  moderate-intensity physical activity, above usual
  activity at work or home, on most days of the
  week.
• For most people, greater health benefits can be
  obtained by engaging in physical activity of more
  vigorous intensity or longer duration.
• To help manage body weight and prevent gradual,
  unhealthy body weight gain in adulthood Engage
  in approximately 60 minutes of moderate- to
  vigorous-intensity activity on most days of the
  week while not exceeding caloric intake
  requirements.
• To sustain weight loss in adulthood Participate
  in at least 60 to 90 minutes of daily
  moderate-intensity physical activity while not
  exceeding caloric intake requirements. Some
  people may need to consult with a healthcare
  provider before participating in this level of
  activity.
• Achieve physical fitness by including
  cardiovascular conditioning, stretching exercises
  for flexibility, and resistance exercises or
  calisthenics for muscle strength and endurance.

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Physical Activity Recommendations

• How much physical activity is required?
• For health benefits?
• 30 minutes/day
• To prevent weight gain?
• 60 minutes/day
• To prevent weigh regain in the formerly obese?
• 60-90 minutes/day

SourceU.S. Dietary Guidelines 2005
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Physical Activity Guidelines for School-Age Youth

• Literature search revealed 1220 possible articles
  gt850 considered for review by panel who
  evaluated rated strength of evidence for number
  of key outcomes.
• School-age youth should participate daily in 60
  minutes or more of moderate to vigorous physical
  activity that is developmentally appropriate,
  enjoyable and involves a variety of activities.
• For youth who have been physically inactive, an
  incremental approach to the 60-minute goal is
  recommended - increasing activity by 10 per week.

Strong, et al. J. Pediatrics. 2005,146732-737.
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ACSM/AHA Recommendations--2007
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Development of ACSM/AHA PA PH

• In early 2000s became evident that an update of
  1995 CDC/ACSM PA PH recommendations needed
  because
• To better explain selected issues that were not
  explicit in the 1995 publication
• Take into account new research addressing
  benefits and dose/response
• Address PA recommendations by other organizations
  that were considered to be in conflict with 1995
  recommendations
• Writing group established that included CDC but
  because 2005 Dietary Guidelines for Americans
  included physical activity recommendations they
  were instructed not to produce additional PA
  recommendations
• Development of two manuscripts by writing groups.

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Development of ACSM/AHA PA PH Update

• Two manuscripts published in MSSE and Circulation
  in 2007
• Physical activity recommendations for generally
  healthy adults age 18-65 years
• Physical activity recommendations for generally
  healthy persons age 65 years and adults of any
  age with selected chronic conditions

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Information on the ACSM/AHA PA Recommendations

• Go to www.heart.org
• Healthy Lifestyles
• Exercise and Fitness
• Can download the pdfs of the two articles
• Go to www.acsm.org
• Physical activity recommendations

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Physical Activity Recommendations for Healthy
Adults Age 18-65 Years 2007

• To promote and maintain good health, adults aged
  18 to 65 years should maintain a physically
  active lifestyle.
• They should perform moderate-intensity aerobic
  (endurance) physical activity for a minimum of 30
  minutes on five days each week or
  vigorous-intensity aerobic activity for a minimum
  of 20 minutes on three days each week.
• 3. Combinations of moderate- and
  vigorous-intensity activity can be performed to
  meet this recommendation. For example, a person
  can meet the recommendation by walking briskly
  for 30 minutes twice during the week and then
  jogging for 20 minutes on two other days.

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Physical Activity Recommendations for Healthy
Adults Age 18-65 Years 2007

• These moderate- or vigorous intensity activities
  are in addition to the light intensity activities
  frequently performed during daily life (e.g.,
  self care, washing dishes, using light tools at a
  desk) or activities of very short duration (e.g.,
  taking out the trash, walking to parking lot at
  store or office).
• Moderate-intensity aerobic activity, which is
  generally equivalent to a brisk walk and
  noticeably accelerates the heart rate, can be
  accumulated toward the 30-minute minimum by
  performing bouts each lasting 10 or more minutes.
  
• 6. Vigorous-intensity activity is exemplified by
  jogging, and causes rapid breathing and a
  substantial increase in heart rate.

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Physical Activity Recommendations for Healthy
Adults Age 18-65 Years 2007

• In addition, at least twice each week every adult
  should perform activities using the major muscles
  of the body that maintain or increase muscular
  strength and endurance.
• 8. Because of the dose-response relation between
  physical activity and health, persons who wish to
  further improve their personal fitness, reduce
  their risk for chronic diseases and disabilities,
  or prevent unhealthy weight gain should consider
  exceeding the minimum recommended amount of
  physical activity.

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Physical Activity Recommendations for Healthy
Adults 65 Years of Age

• Aerobic Activity 30 minutes of moderate
  intensity on 5 days/week or 20 minutes of
  vigorous intensity on 3 days/week.
• Muscle-strengthening activity 8-10 exercises _at_
  10-15 reps performed on 2 non-consecutive days
• Flexibility exercises 10 minutes on 2
  days/week
• Balance promoting activity should perform
  activities that help maintain balance and prevent
  falls.
• Other more activity greater benefit, can
  combined moderate with vigorous to meet goals,
  saety needs to be considered

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Dose-Response to Exercise in Post-Menopausal
Women (DREW)
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Questions Addressed in DREW

• Will sedentary women get any health benefit if
  they perform less than the consensus public
  health recommendation?
• If women perform more than the recommended amount
  will they obtain proportionally greater benefits?
• Does the dose-response relation between exercise
  and outcomes vary for different outcome measures?

Morss GM et al. MSSE 2004 36336
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Percent Change in Absolute VO2 max
TS Church et al. JAMA 2007
Adj. baseline fitness, age, ethnicity and RER
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DREW WHI Data CombinedRisks From WHI for Age
Range 50-59y
DREW Group 4KKW 8 KKW
12KKW METHours/week 3.7 7.5
11.2
Met-Hours/week Median 0 1.5
3.8 7.5
16.7 Range
.1 to 2.5 2.6 to 5.0
5.1 to 10.0 gt10
Manson, NEJM Vol 347 (10) 2002
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Best Exercise Advice to Give to the Public?

• Traditional, structured program--3-5 times/week,
  20-60 minutes/session, relatively vigorous
• Consensus recommendation--accumulate at least 30
  minutes of moderate intensity exercise each day
• The important question is not whether one
  approach is better than the other, but do both
  approaches work?

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What Is the Best Exercise?

• The one you will do regularly
• No matter how excellent the exercise is or how
  effective the program might be, it will not
  produce any benefits for you if you do not do it

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Physical Activity Recommendations for the Future
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Physical Activity Guidelines for Americans - 2008

• October 26, 2006 Secretary of DHHS announced
  plans for developing Federal Physical Activity
  Guidelines for Americans
• Physical Activity Guidelines Advisory Committee
  (PAGAC) appointed in February-March 2007 charge
  is to provide comprehensive report to DHHS on
  the scientific evidence linking physical activity
  to health by March 2008.
• Based on information in report from PAGAC, DHHS
  staff will prepare guidelines and policy report -
  Due October 2008.
• PAGAC with assistance from CDC conducting reviews
  of science published since 1995 for 10 key
  outcomes. Will be augmented with other reviews,
  meta-analysis and studies.
• lthttp//www.health.gov/paguidel
  inesgt .

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Summary

• Systematic research over the past 50 years has
  provided a rich database on the health effects of
  regular physical activity
• Many organizations, governments, and other groups
  around the world have issued physical activity
  recommendations
• Inactivity is widely recognized as a major public
  health problem
• However we still lack coordinated, comprehensive,
  adequately funded efforts to promote physical
  activity for the publics health

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Thank you from Jaxson Woodrow Kennedys Grandpa