What needs to happen to see any effects of exercise training?
- Overload- stress system beyond what its used to
- Specificity- training effects specific to muscles involved in work
- Reversibility- loss of training adaptation
VO2 max from trained to untrained individual
“work is work” Pre-training and post-training same work done at a given VO2. However, that given VO2 is likely to be a higher percentage of the untrained individuals VO2max. The untrained feels like they are working harder at a given VO2
What are the training effects on VO2 max?
Better at O2 extraction
This decreases need for muscle blood flow, spares blood for thermoregulation and increased flow to other organs
Why is stroke volume higher in athletes?
Increased left ventricle thickness, increased left ventricle cavity size, increased volume/preload
What does heart rate follow?
Relative workload or % of VO2 max
Why does heart rate decrease while stroke volume increases?
More parasympathetic tone on the heart decreases heart rate but the heart itself is bigger and therefore have more volume of blood to send out making the stroke volume bigger.
A bigger heart leads to:
- Increased preload (major effector)
- Increase contractility
- Decrease afterload (TPR)
What can an athletes heart look like and why?
Failing heart
The difference is function
1. hypertrophy in muscle = caused by growth hormone
2. Heart failure/hypertension = angiotensin or endothelin
Cardiac volumes for maximal exercise in a trained individual
Cardiac Output = 40 L/min
Heart rate = 200 bpm
Stroke Volume = 200 mL/beat
EF= greater than 80%
Why does preload increase in an athletes heart?
- Increased plasma volume
a. increased total blood volume by 10-30%
b. decreased hematocrit for first bit - Increase venous return = more fill on the heart
- Increase ventricular volume
Why does afterload decrease in an athletes heart?
- Decrease arteriolar constriction
2. Increase maximal muscle blood flow with no change in MAP
Why does contractility increase in an athletes heart?
Have Beta 1 adrenergic receptor sensitivity
Why does a-vO2 difference increase?
- Increased mitochondrial number- increases muscles ability to extract oxygen from blood
- Increased capillary density ergo get more mitochondria
Basically: less work for each mitochondria with training
Alteration in blood pressure at rest with training
No change for normal blood pressure
Hypertensive individuals- decrease SBP and DBP (ace inhibitors cause this too)
Alterations in blood pressure with submax exercise
- Decrease DBP slightly
- Less catecholamines released:
a. decrease fatigue of muscle b/c decrease central command
b. decrease concentration of metabolites which decreases exercise pressor reflex
c. enhanced sensitivity of target tissues to catecholamines
d. enhanced sensitivity to insulin
What is the benefit of enhanced sensitivity to insulin with submax exercise?
Type II diabetics can have a bigger affect of storing glucose in their muscles
Due to decrease insulin from pancreas and increased number of GLUT-4 transporters
Alterations in blood pressure with max exercise
Unchanged mostly
Greater abundance of catecholamine release
Effects of endurance training on ventilation
- Rest = unchanged
- Submax exercise = Fb decreased with training
- Max exercise = increased Ventilation, tidal volume is increased, Fb increases eventually due to hyperventilation
Does the lung limit exercise performance?
No, except in elite athletes it can decrease saturation and ventilatory muscles can steal flow from skeletal muscles during exercise
Metabolic adaptions to training
- Mitochondrial response
- Capillary density
- Muscle fiber change
- Glucose sparing effect
- Blood lactate clearance
Mitochondrial response to training
- increase in number and size
- increase number of ATP per mitochondria
- increase enzymes for aerobic metabolism
Capillary density adaptation during training
- increase number of capillaries per fiber and unit area
a. affects substrate delivery and waste removal - Increase myoglobin content
- capillaries only increase with endurance training due to the oxidative mechanism
Adaptation to muscle fibers
- shift from FG –> to FOG –> SO
- Increase oxidative enzymes fro Kreb’s and Beta Oxidation
- Fibers favor lactate removal due to change in LDH
- Increase intensity and duration recruit more FG fibers
What aids in sparing glucose for the muscles?
- Carbohydrates increase muscle glycogen stores
2. Fats are utilized more with training which spares glycogen
