Exercise in Extreme Conditions

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Exercise in Extreme Conditions

• PED 4900

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Air Pollution
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Carbon Monoxide

• A primary, orderless pollutant formed from
  automobiles, factories, etc.
• 210-230 times greater affinity to RBC than oxygen
• Less oxygen bound to hemoglobin and myoglobin
• Increase anaerobic metabolism (lower lactate
  threshold, decrease endurance and VO2max).

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Smoking

• Decrease performance if smoke 10 or fewer
  cigarettes or ride1 hr in a car with a smoker
• Increase pulmonary airway resistance and oxygen
  cost of breathing

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Ozone

• A secondary pollutant formed when ultraviolet
  rays hit oxygen
• Most common photochemical oxidant
• When concentrated, eye irritation, chest
  tightness, breathlessness, coughing, and nausea.
• Reduces oxygen transfer at the lung

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Sulfur dioxide

• Formed from burning coal and oil
• Upper airway irritant that can cause significant
  discomfort

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Exercise and Pollution

• Air pollution is greatest during commute hours
  and warmest time of day
• Cause bronchioconstriction which is exaggerated
  during exercise
• Mouth breath worse than nose breathing less
  filtering
• Studies show decrement in performance with
  significant air pollution

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Biological Rhythms and Travel
The Beta-Q Biorhythms program charts the three
cycles in separate frames underneath each other
for ease of viewing and uses daily indicator bars
to visually indicate the state of the rhythms on
the view date, with colors representing the
phases, critical and mini-critical days.
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Biological Rhythms and Travel

• Physiological functions follow certain rhythms
  Circadian, Cicaspetian, Circalunar, and
  Circa-annual.
• Examples of functions with regular rhythm
• Sleep, body temperature, heart rate, blood
  pressure, metabolic rate hormone secretion
• Strength, power, reaction time, and RPE.
• Most studies show performance is maximized in the
  afternoon

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Jet lag

• Characterized by fatigue, malaise, sluggishness,
  decrease reaction time, and disorientation
• Cause may be due to loss of sleep, irregular and
  unfamiliar meals, dehydration, and disturbance of
  biological clock
• Flying can increase dehydration due to low
  humidity (20) inside the cabin
• Eastbound travel seems to cause more problems.

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Micogravity, Immobilization, and Bed Rest
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Micogravity, Immobilization, and Bed Rest

• Less gravitational pull as an object moves
  further away from the earth
• At 8,000 miles body weight is only 25 of its
  value on earth
• At 210,000 miles bodyweight is 0 of its value on
  earth
• No or microgravity unloads the posture muscles
  and any stress to the bones

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Muscle

• Atrophy from a decrease in protein synthesis but
  some strength is maintained
• 17 day space flight produced no change in muscle
  strength but a 8-11 decrease in size
• 28 day space flight produced 10-20 decrease in
  strength and 10 decrease in size
• Resistance training in space can attenuate the
  loss of muscle size and function

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Bone

• Bone losses range from 0-6
• Greater loss from weight baring bones (e.g.
  calcaneus)
• Could be due to a combination of reduced bone
  formation and increased bone resorption

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Cardiovascular

• Reduction in plasma volume
• Reduced hydrostatic pressure and thus venous
  pooling
• Increase venous return and cardiac output
• Increase blood flow through kidneys
• Result in orthostatic hypotension upon return to
  earth

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Exercise on the International Space Station

• The cycle ergometer looks much like an exercise
  bicycle. It gives aerobic conditioning to legs
  and arms while also conditioning the heart. With
  monitors to record vital signs and straps to keep
  them in place, pedaling the ergometer provides
  toning and conditioning the astronauts' need.
• The treadmill used in space is a bit different
  than one used on Earth. Because astronauts are
  nearly weightless, they need to be harnessed to
  the machine and weighted down as they walk.
  Otherwise, even if they managed to stay in place
  on the treadmill, their exercising would be
  nearly effortless and ineffective.
• The Interim Resistance Exercise Device (IRED)
  uses cylinders filled with disks to create a
  push-pull resistance. Astronauts can exercise the
  muscles that don't get much action in
  microgravity.

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Ultra-Endurance
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Ultraviolet exposure in the Ironman triathlon
MATTHIAS MOEHRLEDepartment of Dermatology,
University of Tuebingen, GERMANYMEDICINE AND
SCIENCE IN SPORTS AND EXERCISE 2001331385-1386

• Purpose Skin cancer is increasing worldwide and
  exposure to ultraviolet (UV) radiation is thought
  to be the most important environmental risk
  factor. People practicing outdoor sports are
  exposed to considerable amounts of UV radiation
  from the sun.
• Methods Three triathletes participated in the
  Ironman Triathlon World Championships 1999 in
  Hawaii (3.9-km swim, 180.2-km bike, 42.4-km run).
  They attached Bacillus subtilis spore film
  dosimeters (VioSpor) on the back between their
  shoulders. The dosimeter system measured
  cumulative biologically weighted erythemal UV
  exposure. UV exposure is given in minimal
  erythema doses (1 MED corresponds to 250 Jm-2 at
  298 nm).
• Results The mean personal UV exposure was 8.3
  MED (6.9-9.7 MED) after 843 to 944 h of
  competition corresponding to 0.8 to 1.3 MEDh-1
  (bike and run). The athletes were sunburned
  despite the use of water-resistant sunscreen (SPF
  25) on sun exposed skin.
• Conclusion The International Radiation
  Protection Agency has issued guidelines for
  professional UV exposure. Ironman triathletes
  considerably exceeded these limits of exposure
  similar to other outdoor sports. Professional and
  amateur athletes should be aware of hazards
  caused by UV radiation. Adequate protection by
  water-resistant sunscreens and clothing as well
  as training and competition schedules with low
  sun exposure seem to be a reasonable
  recommendation.

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ULTRA-ENDURANCE CYCLING A FIELD STUDY OF HUMAN
PERFORMANCE DURING A 12-HOUR MOUTAIN BIKE RACE.
JON LINDERMAN, TIM DEMCHAK, JULIE DALLAS, JANET
BUCKWORTH. JEPONLINE. 20036(3)10-19.

• TO INVESTIGATE CHANGES IN PHYSIOLOGICAL AND
  PSYCHOLOGICAL FUNCTION DURING ULTRA-ENDURANCE
  EVENTS, 6 HEALTHY CYCLISTS (31.51.6 YEARS) WERE
  STUDIED DURING A 12-HOUR MOUNTAIN BIKE RACE.
• SUBJECTS COVERED 119-170 KM, AT AVERAGE
  VELOCITIES OF 11-14 KM/HOUR.
• DURING THE FIRST TWO HOURS OF THE EVENT HEART
  RATES AVERAGED 155-157 BEATS/MIN, DECLINED
  SIGNIFICANTLY DURING THE THIRD HOUR (14214
  BEATS/MIN Plt0.05), AND WAS LARGELY UNCHANGED
  THROUGHOUT THE REMAINING NINE HOURS OF THE RACE.
  
• SUBJECTS CONSUMED 1550-3300 KCALS DURING THE
  EVENT WITH AN AVERAGE OF 66276 G OF
  CARBOHYDRATE. ALTHOUGH SUBJECTS CONSUMED
  4500-6400 ML OF FLUID DURING THE RACE, HYDRATION
  STATUS, ASSESSED FROM CHANGES IN BODY WEIGHT,
  INDICATED A DEHYDRATION INDIRECTLY QUANTIFIED AS
  A 4 DECREASE IN BODY WEIGHT PRE- TO POST RACE
  (2.31.4 KG Plt0.05).
• USING THE 10-POINT BORG SCALE SUBJECTS RATING OF
  PERCEIVED EXERTION (RPE) INCREASED HOURLY FROM
  4.01.3 AFTER THE FIRST HOUR OF COMPETITION TO
  9.21.0 DURING THE TWELFTH HOUR OF COMPETITION
  (Plt0.05).
• PROFILE OF MOODS STATE (POMS) ADMINISTERED DURING
  THE EVENT REVEALED DECLINES IN VIGOR PRE- TO
  POST-RACE (11.52.3 VS. 3.81.7 Plt0.05), WITH
  CONCOMITANT INCREASES IN FATIGUE SCORES (5.32.8
  VS. 19.30.5 Plt0.05).
• RESULTS OF THE PRESENT INVESTIGATION SUGGEST
  GREATER DECLINES IN MENTAL THAN PHYSIOLOGICAL
  FUNCTION DURING PROLONGED OFF-ROAD CYCLING
  COMPETITION.

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Energy expenditure during 2 wk of an
ultra-endurance run around Australia REBECCA J.
HILL PETER S. W. DAVIESSchool of Human Movement
Studies, Faculty of Health, Queensland University
of Technology, Brisbane, Queensland, AUSTRALIA
and Childrens Nutrition Research Centre,
Department of Paediatrics and Child Health, Royal
Childrens Hospital, Binsbane, Queensland,
Australia.MEDICINE AND SCIENCE IN SPORTS AND
EXERCISE 200133148-151

• Purpose For ultra-endurance athletes, whose
  energy expenditure is likely to be at the
  extremes of human tolerance for sustained periods
  of time, there is increased concern regarding
  meeting energy needs. Due to the lack of data
  outlining the energy requirements of such
  athletes, it is possible that those participating
  in ultra-endurance exercise are compromising
  performance, as well as health, as a result of
  inadequate nutrition and energy intake. To
  provide insight into this dilemma, we have
  presented a case study of a 37-yr-old
  ultra-marathon runner as he runs around the coast
  of Australia.
• Methods Total energy expenditure was measured
  over a 2-wk period using the doubly labeled water
  technique.
• Results The average total energy expenditure of
  the case subject was 6321 kcald-1. Based on the
  expected accuracy and precision of the doubly
  labeled water technique the subjects total
  energy expenditure might range between 6095 and
  6550 kcald-1. The subjects average daily water
  turnover was 6.083 L over the 14-d period and
  might range between 5.9 L and 6.3 Ld-1.
• Conclusions This information will provide a
  guide to the energy requirements of
  ultra-endurance running and enable athletes,
  nutritionists, and coaches to optimize
  performance without compromising the health of
  the participant.

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