Assessing Aerobic Fitness for Work

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Trent Occupational Medicine Annual
Symposium Fit Notes or Sick Notes
Assessing Aerobic Fitness for Work
Kevin Sykes Professor of Occupational Health
FitnessDirectorPostgraduate Centre for Exercise
Nutrition ScienceUniversity of Chester
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Youve got to be fit to handle this type of Job
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Youve got to be fit to handle this type of Job

• High levels of HR BP
• Faster recovery with fitter individuals
• Less injury risk for fitter individuals
• Lack of Fitness major stressor in these
  situations

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2 firefighters same job!
Fit
Unfit
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100HRMax
85HRMax
Intense physical activity is a strong triggering
factor for heart attack, especially among
physically inactive and unfit individuals.
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• Firefighting is well known to be a dangerous
  occupation.

What is less well known is that the most frequent
cause of death among US firefighters is not
burns, accidents or smoke inhalation. ..but is.
Heart Disease
Heart Disease causes 45 of the deaths that occur
while on duty (US study).
Firefighters are x2 as likely to die from a heart
attack in the line of duty than police officers
and x3 more likely than paramedics.
Kales et al. (2007) New England J. Med
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Deaths from Heart Disease among US Firefighters
(1994-2004)

• Fire suppression is associated with up to 100x
  risk than for non-emergency duties.
• Aerobic Fitness is a key factor in prevention
• 70 of US Fire Departments lacked programs to
  promote fitness and health.
• Most do not require firefighters to exercise
  regularly, undergo periodic medical examinations,
  fitness tests or have mandatory return-to-work
  evaluations after a major illness.

Kales et al. (2007) New England J. Med

• Firefighters may be required to work at maximal
  levels of exertion.
• To someone not in good shape this presents
  serious risk.
• Firefighters with low aerobic fitness have a
  90 greater risk
• of MI than those who are aerobically fit.

Peate et al (2002) J.Occ. Environ. Med.
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Fitness for Firefighting

• VO2Max has been consistently shown to be the best
  predictor of performance in simulated
  firefighting tasks (Heyman, 2002 Sykes, 2002)

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What is VO2

• VO2/min oxygen uptake per minute
• Often termed Metabolic Rate
• Measured in litres/min or mlsO2/kg/min
• How is it Calculated?
• VO2/min Minute Ventilation x O2 absorbed by
  body
• e.g. Rest VO2/min 10 x 3 0.3 l/min
• Typical values 0.3-0.5 l/min males
  (300-500mls/min)
• 0.2-0.4 l/min - females (200-400mls/min)
• Rest VO2/min 3.5 mlsO2/kg/min 1MET
• Moderate Exercise (80kg person)
• VO2/min 50 x 4 2.0 l/min 2000mls/80kg
  25mlsO2/kg/min (/3.5) 7METS
• Vigorous Exercise (80kg person)
• VO2/min 100 x 3.5 3.5 l/min 3500mls/80kg
  35mlsO2/kg/min (/3.5) 10METS

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Approximate Energy Cost of Selected Activities
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Assessment of Aerobic Fitness
VO2Max The maximum amount of oxygen the body
can take in (lungs), transport (heart
circulation) and use (muscles) Aerobic
Capacity mlsO2/kg/min
highest rate of O2 consumption during maximal,
exhaustive exercise - best objective
laboratory measure of cardiorespiratory fitness
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CPX Testing

• Units
• mlsO2/kg/min
• METS

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Cardiopulmonary Exercise Testing (CPX)Treadmill
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Cardiopulmonary Exercise Testing (CPX)Treadmill
16 METS
12 METS
57 mlsO2/kg/min
44 mlsO2/kg/min
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Norms for Aerobic Capacity (mlsO2/kg/min) M
ales Age Group
Females Age Group
Sykes 1996

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VO2Max Age
VO2Max (mlsO2/kg/min)
70
60
o
o
o
o
x
x
o
50
x
o
o
x
x
o
x
40
o
x
x
o
Males Females
x
x
30
20
0 10 20 30 40 50 60 70
Age
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Assessment of Aerobic (Cardiorespiratory) Fitness

• Laboratory VO2Max Test
• Prediction Tests
• Shuttle Run (Bleep Test)
• Chester Step Test (CST)
• Cycle Ergometer Test (Astrand)
• Chester Treadmill Walk Test (CTWT)
• Distance Walk/ Run (1-mile, 1.5-mile,
  12-min)
• Rowing Ergometer
• Stepper

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Multi Stage Shuttle Run Test(Bleep Test)
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20-metre Shuttle Run Test Multistage Fitness
Test Bleep Test

• running between two lines 20m apart in time to
  recorded beeps
• pace increase gradually
• subject runs to exhaustion
• score is level no. of shuttles reached before
  unable to keep up with beeps
• score can be converted to a VO2max

• Police Recruit Applicant Fitness Test Modified
  to 15m

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Multi-Stage Shuttle Run Test (Bleep Test)

• Progressive maximal
• Easy to administer
• Caution needed when administering the test -
  requires maximum effort
• Check there are no medical contraindications

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Predicted VO2Max Tables Loughborough University,
1987
back to top
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Predicted VO2Max Tables Loughborough University,
1987
back to top
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20m Shuttle Run

• Suitable for regularly active, those used to
  maximal exertion
• Not suitable for older, less fit, those not
  used to maximal exertion or with medical
  contraindications
• Validity high correlation to VO2max in fit
  active.
• Lower validity in older less fit. Higher
  validity in males v females.
• Reliability depends how strictly the test is run
  amount of practice allowed
• Higher reliability in fit people - and better in
  males.
• Use CD not tape (which may stretch with wear)

• Advantages large groups can perform the test for
  minimal costs.
• Requires maximum effort
• Disadvantages practice motivation influence
  scores, some dont give max effort, scoring can
  be subjective, environment conditions affect
  results (e.g. outdoor, indoor, type of surface,
  turning area/space, numbers, encouragement).
• Maximum performance requires mental toughness,
  pacing, turning agility good physical
  conditioning

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• a submaximal test to predict aerobic capacity
• subject steps onto and off step at pace set by
  metronome (audio CD)
• step height 6, 8, 10 or 12ins
• step rate increases every 2 minutes
• 5 Levels (15, 20, 25, 30, 35 steps/min)
• test ends when subjects reaches 80HRMax
  (220-age) or RPE14 (Mod. Hard)
• data plotted on graphical datasheet or entered
  into software calculator

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Test ends when Subject reaches 80HRMax, or RPE14
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80-85HRMax
Borg Scale Rating of Perceived Exertion
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• Suitable for wide range of ages abilities,
  males females
• Not suitable for obese or other medical
  contraindications (e.g. knee/hip problems,
  beta-blocked patients)
• Validity high correlation to VO2max affected
  by variations in HRMax anxiety
• Accuracy 10 variability
• Reliability excellent test/re-test
• Use CD not tape (which may stretch with wear)

• Advantages simple to administer, inexpensive,
  portable, easy to calibrate, submaximal, wide age
  ability range, good estimate, 1-to-1, visual
  feedback, software calculator, exercise
  prescription, use of RPE
• Disadvantages not an exact measure, graphical
  interpretation, affected by nerves poor rhythm,
  1-to-1

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Astrand Cycle Test

• Submaximal, 6-min test to predict aerobic
  capacity
• 50 revs/min pedal frequency
• Commence exercise at 50W, increase workload by
  50W (25W females) every min until HR reaches
  around 70-80HRMax (130-160b/min)
• Exercise for 2-3mins at steady state HR
• Use Tables/Software to predict aerobic capacity
  from Age, Sex, 6-min HR Workload

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50W 100W 150W 200W
250W
100W 150W 200W
250W
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Astrand CycleTest
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Astrand Cycle Test

• Suitable for wide range of ages abilities,
  males females
• Not suitable for those with medical
  contraindications (e.g. knee problems, etc),
  beta-blocked patients
• Validity high correlation to VO2max affected
  by variations in HRMax anxiety
• Accuracy 10 variability
• Reliability excellent test/re-test

• Advantages simple to administer, submaximal,
  wide age ability range, good estimate, 1-to-1,
  used worldwide since 1960s
• Disadvantages not an exact measure, affected by
  nerves poor pedal rhythm, 1-to-1, local leg
  muscle fatigue, cycle needs careful calibration

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• Toolkit of fitness tests with support
• documentation

• Recommendation for a national
• standard for aerobic fitness

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Typical aerobic cost of fire fighting
35mlsO2/kg/min
To be working at 80-85 of maximum, aerobic
capacity needs to be at least 42mlsO2/kg/min
Proposed minimum aerobic fitness standard
42mlsO2/kg/min
Firefit Steering Group (2007).
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Norms for Aerobic Capacity (mlsO2/kg/min) Males
Age Group
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Females Age Group
Sykes 1996

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Assessment of Aerobic Capacity(Cardiorespiratory
Fitness)

• Chester Step Test
• MultiStage Shuttle Run Test (Bleep Test)
• Chester Treadmill Walk Test
• Treadmill Ramp Protocol with Gas Analysis

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Suggested Order for In-Service CR Fitness Testing
CST
MSSRT
Gas Analyser Available
No Gas Analyser Available
CHESTER TREADMILL WALK TEST
TREADMILL RAMP PROTOCOL WITH GAS ANALYSIS
Firefit Steering (2007)
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Chester Treadmill Walk Test6.2km/hr (3.75mph)

• A 12-minute (max) progressive, treadmill walk
  test designed to identify individuals capable (or
  not) of reaching the proposed fitness standard of
  42mlsO2/kg/min.

Sykes (2008)
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Chester Treadmill Walk Test
ACSM 2006 Metabolic Equations
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Chester Treadmill Walk Test
(6.2km/hr)
Procedures 1. Check there are no medical
contraindications to performing exhaustive
exercise 2. Subject walks at 6.2km/hr at 0 for
2mins 3. Every 2mins increase gradient by 3 4.
Test is completed after 12mins 5. Test should be
stopped if subject is showing overt signs of
distress and exhaustion

• Notes
• For some this will be a maximal test, whilst
  for others this will require only sub-maximal
  effort.
• If the subject can only complete 8 mins, then
  the aerobic capacity can be estimated as 31
  mls02/kg/min).

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0-2mins 0 14mlsO2/kg/min
CTWT 6.2km/hr
2-4mins 3 19mlsO2/kg/min
4-6mins 6 25mlsO2/kg/min
6-8mins 9 31mlsO2/kg/min
8-10mins 12 36mlsO2/kg/min
10-12mins 15 42mlsO2/kg/min
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Chester Treadmill Walk Test for the prediction of
Aerobic Capacity (Sykes 2008)
Vi
Draft
Level 1 2
3 4 5
6
Gradient 0 3
6 9 12
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Procedures 1. Check there are no medical
contraindications to vigorous exercise 2. Subject
walks at 6.2km/hr at 0 for 2mins 3. Every 2mins
increase gradient by 3 4. Test is completed when
HR reaches 80 or RPE14 5. Test should be
stopped if subject is showing overt signs of
distress and exhaustion
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Chester Treadmill Walk Test for the prediction of
Aerobic Capacity (Sykes 2008)
JP
40 180
144
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Vi
90 107 125 138
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Draft
Level 1 2
3 4 5
6
Gradient 0 3
6 9 12
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Procedures 1. Check there are no medical
contraindications to vigorous exercise 2. Subject
walks at 6.2km/hr at 0 for 2mins 3. Every 2mins
increase gradient by 3 4. Test is completed when
HR reaches 80 or RPE14 5. Test should be
stopped if subject is showing overt signs of
distress and exhaustion
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Health Safety

• Complications associated with fitness testing are
  relatively low, however
• Ability to maintain high level of safety depends
  on knowing when NOT to perform a fitness test
• Pre-participation health screening test
  administrator should ensure there are no medical
  contraindications to performing the test
• Higher risk with maximal fitness test
• Need for knowledgeable, highly competent testers

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Fitness Testing must be conducted by
knowledgeable and skilled testers
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Trent Occupational Medicine Annual
Symposium Fit Notes or Sick Notes
Assessing Aerobic Fitness for Work
Kevin Sykes Professor of Occupational Health
FitnessDirectorPostgraduate Centre for Exercise
Nutrition ScienceUniversity of Chester
Questions
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'Healthy Working'
An Integrated Workplace Health Fitness
Programme for Operational Civilian Staff ..
OH, FBU, HR, HS and Welfare ..
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Workplace Health Fitness Programme

• Voluntary scheme exercise taken at managers
  discretion
• Wholetime stations X-trainers, bikes, rowers,
  versa, fit balls multigym free weights
• Retained stations rower bike
• CST test every 18 months (administered by
  Fitness Advisers)
• Full medical every 3 years (inc. CST, grip,
  body fat, etc)
• Reduced membership at local gyms

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Workplace Health Fitness Programme

• Systematic reduction in sickness rates injuries
• Systematic improvements in BP, BW, BMI, Waist,
  Lipids, Fitness

ROSPA Gold Award 2007