edu2exp exercise & performance 1 environment and exercise

EDU2EXP Exercise & Performance

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Environment and Exercise


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Thermoregulation


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Body temperature

• Different temperatures:

– Surface / Skin

– Core body

– Inner ear

– Rectal

– oral


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Mechanisms of Heat Loss/gainMechanisms of Heat Loss/gain

• Radiation– The release of heat via electromagnetic heat waves

• Conduction

• Convection– Carrying heat on air currents

• Evaporation


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Primary mechanisms

• At rest?

• During exercise??


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Mechanisms of Heat ConservationMechanisms of Heat Conservation

• Vascular adjustments

• Muscular activity

– Voluntary physical activity

– Involuntary- Shivering

• Hormonal adjustments


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Mechanisms Facilitating Heat LossMechanisms Facilitating Heat Loss

• Circulatory adjustments

• Evaporation (sweating)

• Hormonal adjustments


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Circulatory AdjustmentsCirculatory Adjustments

Two competitive cardiovascular demands exist during exercise in the heat

2) Peripheral blood flow to the skin must increase to transport metabolic heat from exercise for dissipation at the body’s surface


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Evaporation depends on

• Temperature and humidity of air

• Convective air currents


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Clothing

• However if sweat is not absorbed and drawn away from skin to be kept dry, -> overheating


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Exercise in the Heat


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Consequences of DehydrationConsequences of Dehydration

• Reduced plasma volume

• Increased submaximal heart rate

• Impaired ability to thermoregulate


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Hyperthermia

• Prevention

– Drink fluids before and after and have breaks every 15-30 mins

– Clothing

• Treatment

– Immerse in ice bath/ cold water


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Clothing for the heat

• Loose fitting to allow convective air currents near skin

• Wet allows increased evaporation

• Colour– Dark = absorbs radiant heat– Light – reflects radiant heat


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Factors Affecting Heat ToleranceFactors Affecting Heat Tolerance

• Acclimatisation

• Exercise training

• Age

• Gender

• Body composition

• Hydration


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Acclimatisation to heat

• Training increases heat tolerance

• As does 9-14 days of exercising in heat


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Exercise in the Cold


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Cold• Physiological

– Peripheral Vasoconstriction – Shivering – Increased consumption O2 to compensate for that used in shivering

- Cold muscle = decreased contractile force• Particularly when fatigued• Large inner muscles insulated and protected• Peripheral muscles decreased dexterity

• Behavioural adjustments– Huddle– Voluntary movement– Put more clothes on– Exercise indoors


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Exercise in water in the cold• Body loses heat 4 x as fast in cool water

as in air the same temperature Shivering


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Exercise and AltitudeExercise and Altitude


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Exercise at AltitudeExercise at Altitude

– Reduced barometric pressure

– Reduced relative humidity

– Reduced ambient temperature


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Immediate adjustments to altitude above 2300 m

Immediate adjustments to altitude above 2300 m

• Hyperventilation

– Chemoreceptors detect that not getting enough oxygen

• Cardiovascular

– Increased HR and cardiac output

– At rest and during submaximal exercise


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Exercise Capacity at AltitudeExercise Capacity at Altitude

• Aerobic capacity

– 1-3.5% reduction Vo2 max every 300m increase from 1500 m

– Greater rate decline for trained athletes

• Circulatory factors

– Decreased MHR and SV


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Acclimatisation

• Adaptive responses to improve one’s tolerance to altitude

• Additional 610 m = 1 week


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Blood volume– Increased RBC production– Increased hemoglobin content– Increase in overall blood volume and an increase in oxygen carrying

capacity.

Muscle adaptations Increased muscle capillary density

Longer-Term AdjustmentsLonger-Term Adjustments


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Altitude TrainingAltitude Training

• Acclimation to altitude improves one’s capacity to exercise at altitude

• However inability to train at equivalent intensity no improvement Vo2 max on return to sea level

Live High, Train Low ???

Does altitude training improve sea-level performance ??


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SummarySummary

• Environment critical to optimal performance

• Be aware of environment in case of negative effects

• Use to your advantage

– Heat

• Humidity

– Cool

– Altitude


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Ergogenic aids


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Ergogenic aids

1- stimulate CNS

2-supplemental fuel source

3- reducing or neutralising performance inhibiting metabolic by-products

4- facilitating recovery from strenuous exercise

Substances and procedures believed to improve athletic performance.They can:


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CaffeineCaffeine• Enhances endurance performance by

– Increased alertness, concentration and reaction time

– Elevated mood

– Increasing time to fatigue

– Reducing perception of effort

• May improve sprint & power performances


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Anabolic SteroidsAnabolic Steroids• Synthetic derivatives of testosterone

• Designed to maximize anabolic effects– Enhance protein synthesis– Inhibit protein degradation

• Increase skeletal muscle hypertrophy and strength

• Facilitates recovery from high intensity training


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Associated Side Effects of Anabolic Steroids

Associated Side Effects of Anabolic Steroids

•Personality changes

•Reduced sperm count in men

•Menstrual cycle disruption in women

•Masculinisation in women

•Breast enlargement in men

•Liver damage

•Cardiovascular disease

•Impotence in men


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Blood doping

• Practice of illicitly boosting the total volume of RBC in order to enhance athletic performance.

Benefits

– >Increased RBC can carry more O2, which can improve an athlete’s aerobic capacity and endurance.


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Side effects

• Increase in blood viscosity heart has to work harder to pump the thicker blood and the blood is more prone to clot.

• Increased risk of heart attack, stroke and blood clots in the lung.

• The risk is exacerbated by dehydration which often occurs during endurance exercise.

edu2exp exercise & performance 1 environment and exercise

Documents

heat toleranceas

transport metabolic

ones capacity

shivering cold muscle

muscle adaptations

improvement vo2 max

increased consumption

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