Physiology of Exercise Flashcards
Placebo Effect
a beneficial effect produced by a placebo drug or treatment, which cannot be attributed to the properties of the placebo itself, therefore be due to the patient’s belief in that treatment
Factors that limit research of ergogenic aids
- small effects missed by studies
- equipement inaccuracy
- research variability
testing situations - reliance on supplement label that is inaccurate
Strength on evidence in ergogenic aids
- anecdotes, observations, opinions, editorials
- case studies
- observational studies
- randomized controlled crossover trials
- meta analyses and systematic reviews
Bicarbonate benefits
- increased blood pH and buffering capacity
- delayed onset anaerobic fatigue
Bicarbonate effects
- increased all out performance for 1-7 minutes
- enhanced hydrogen ion removal from muscle fibers
Bicarbonate risks
-GI discomfort (bloating, comfort)
-Sodium citrate→ similar results without risks
B- Alanine benefits
Increased intracellular buffering
B- Alanine effects
Increased muscle cell carnosine levels
B-Alanine risks
Paraesthesia (tingling of the skin)
Leucine benefits
stimulates protein synthesis
Leucine effects
Stimulates mTOR, which increases the rate of muscle protein synthesis
Leucine risks
little to no risk
Creatine benefits
- Enhanced peak power production during intense exercise
- Improved recovery from high intensity exercise
- Enhanced muscle mass and strength
Creatine effects
increased muscle PcR
Creatine risks
safe to use and potentially positive effects on the brain
Nitrate benefits
Increased delivery of O2 and nutrients to active skeletal muscle
Nitrate effects
- Improved time to exhaustion
- Reduced O2 consumption
- Reduced systolic blood pressure
Nitrate risks
adverse effects in people taking
Caffeine benefits
stimulant (adenosine receptor antagonist)
Caffeine effects
benefits for endurance and repeated high intensity performance
Carnitine benefits
-Transports fatty acids from sarcoplasm to mitochondria
-Decreases fatty acid oxidation
-Buffering ability to reduce production of lactic acid
Carnitine effects
Reduced muscle damage, enhanced muscle blood flow, increased muscle mass
Carnitine risks
GI discomfort
Stimulants- how they work
Stimulant risks
- death
- cardiac arrhythmia
- addiction
- side effects: nervousness, anxiety, aggression, insomnia
Anabolic steroid benefits
- increased recovery time
- reduced fat mass
- facilitation of recovery after exhaustive exercise
Anabolic steroid effects
- increased body mass
- increased total body potassium and nitrogen
- increased muscle size and strength
- decreased muscle fiber damage after exhaustive lifting
Anabolic steroid risks
children- small adult stature
men- excess estrogen (breast enlargement), testicular atrophy, reduced sperm count
women-disrupted menstruation/ovulation, development of masculine sex characteristics
Growth hormone benefits
-stimulation of protein, nucleic acid synthesis
- stimulation of bone growth
- stimulation of IGF-1 synthesis
- increase in FFA mobilization, decreased fat mass
- increase in blood glucose levels
- enhanced healing after injury
Growth Hormone risks
- acromegaly–> skin thickening
- enlargement of internal organs
- cardiomyopathy
- hypertension
- glucose intolerance, diabetes
Blood doping
any means by which red blood cell count increases
-Transfusion of red blood cells
- Infusions of artificial hemoglobin
- Use of EPO or EPO stimulating substances
Blood doping effects
- increased Vo2max (long term)
- enhanced endurance performance (short term)
Blood doping risks
- blood too viscous –> clotting
- blood matching complications
- exposure to bloodborne diseases
Moderate altitude
2000-3000m
- affects well being in unacclimated people
- performance and aerobic capacity decreased
High altitude
3000-5000m
- acute mountain sickness
- performance decreased
Extreme altitude
5500+
- severe hypoxic effects
Acute mountain sickness
reduced air pressure and lower oxygen levels
- headache
- nausea
- vomiting
- fatigue and weakness
- dizziness or lightheadedness
*stay well hydrated
Hypoxia
deficiency of oxygen reaching the body’s tissues
-not enough oxygen in the blood
- shortness of breath
- rapid breathing
- rapid heart rate
Sea level and altitude PO2 differences
sea level- 159
altitude- 132, 122, 90, 53
Humidity at altitude
- cold air holds less water
- air at altitude is very cold and dry
- dry air = quick dehydration via skin and lungs
Air temperature at altitude
temperature decreases 1c per 150m ascent
Acute altitude exposure
- pulmonary ventilation increased immediately (rest and submaximal)
Acute altitude exposure- alkalosis
respiratory alkalosis = high blood pH
- oxyhemoglobin curve shifts left
- prevents further hypoxia-driven hyperventilation
Acute altitude exposure- O2 transport
decreased alveolar PO2 –> decreased O2 hemoglobin saturation
- oxyhemoglobin dissociation curve shifts left
- shape and shift of curve minimize desaturation
Acute altitude exposure- cadiovascualr system
-increased ventilation at altitude = hyperventilation
- cardiac output increases
Acute altitude exposure- metabolic
- basal metabolic rate increases
- increased anaerobic metabolism = increased lactic acid
Altitude exposure and performace
Vo2max decreases as altitude increases past 1500m
- atmospheric PO2 less than 131
- due to decreased arterial Po2 and Q max
- aerobic exercise performance affected most by hypoxic conditions at altitude
- anaerobic performance unaffected
Acclimation- pulmonary adaptations
increased ventilation at rest and during submaximal exercise
- resting ventilation rate 40% higher than at sea level
- submaximal rate 50% higher
Acclimation- cardiovascular
study of runners showed no major cardiovascular adaptions
- 2 months at altitude= more tolerant hypoxia
- no changs in aerobic capacity
Acclimation- muscle/metabolic
muscle function and structure changes
- decreased muscle mass due to weight loss
muscle metabolic potential decrease
- oxidative capacity decreased
Optimizing altitude performance
Live high, train low
Acute altitude mountain sickness
onset 6-48 after arrival
- headache, nausea/vomiting, dyspnea, insomnia
*low ventilatory response to altitude
*accumulation of Co2 acidosis
HAPE
high altitude pulmonary edema
- accumulation of fluid in the lungs air sacs and the surrounding tissues
- shortness of breath, cough
*supplemental oxygen
HACE
High altitude cerebral edema
- affects the brain and swelling of brain tissue due to fluid leakage and increased pressure within the skull
- confusion, ataxia
*supplemental oxygen
Microgravity- muscle changes
- decrease in type II fibers
- muscle atrophy due to decreased protein synthesis
- loss of muscle strength
- reduced muscle fiber capillary density
Microgravity- bone changes
lose bone mineral density
Microgravity- cardiovascular function
- body fluid shifts headwards
- reduced blood pressure
- reduced heart rate
- increased stroke volume initally
- decreased plasma volume
