Exercise Principles and Physiological Response to Exercise

what is physical activity?

this is activities that we do each day that utilize energy expenditure, so occupational household or other activities.

what is exercise?

structured physical activity with a goal in mind

what is physical fitness?

a set of attributes that are either health or skill related, and the measurability of those skills

what are the 7 principles for exercise prescription?

1. individualized

2. specificity

3. progressive

4. overload

5. adaptation

6. recovery

7. reversibility

MAINTENANCE

how can we determine how hard someone is working? what if you cant use that method?

heart rate!

if someone is on a beta blocker that stunts their HR you can use RPE

how many minutes of moderate intensity aerobic activity should adults get each week?

150minutes

how many days of muscle strengthening activities should adults have each week?

2

if you use the Borg test, what does each level represent?

so take your BORG score, multiply it by 10 and that should give you an associated HR

what is Reps in Reserve?

this is the idea that you can use for resistance training when you ask the participant how many more reps they think they can handle with that weight (its a way of measuring RPE)

kids and teens ages 6-17 need how many minutes of moderate-intensity aerobic activity a day?

60 mins

how many days of muscle strengthening activities should kids and teens have?

3x a week

how many days of bone-strengthening activities should kids and teens have?

3x a week

what are the 3 steps of the physiology of the pulmonary system?

1. ventilation: the air coming in and out

2. Respiration: gas exchange

3. Cellular Respiration: transport of gasses to peripheral tissues

movement of air in and out of the lungs results from what?

the pressure differences which are affected by lung compliance, elasticity, surface tension, intrapulmonary and atmospheric pressures

inspiration has what charge of intrapulmonary pressure?

negative

expiration occurs when what happens?

intrapulmonary pressure exceeds atmospheric pressure

what is transpulmonary pressure?

the difference between intrapulmonary and intrapleural pressures

what does transpulmonary pressure do?

it makes sure the lungs stay near the chest wall

what is distensibility of lung tissue?

compliance

what is the tendency of a structure to return to its initial size after being distended?

elasticity

what is resistance to airflow affected by?

pressure differences, diameter, and length of airway

what is our respiratory response to exercise?

1. exercise causes an increased carbon dioxide in the blood

2. higher CO2 causes a lower pH

3. brain senses the lower pH

4. brain sends more frequent messages to breathing muscles, which then contract more frequently

5. carbon dioxide is lost from lungs more rapidly

6. when exercise stops, breathing returns to normal

at rest, what is the distribution of blood in capillaries?

its uneven to the point that some capillaries decrease function/ability for diffusion

why is the perfusion rate so low at rest in the capillaries? why does it change with exercise?

because of gravity, when you exercise you eliminate gravity

during exercise, what happens to the blood distribution in the capillaries?

it increases! increased cardiac output causes an increase in pulmonary perfusion

optimal respiration (gas exchange) occurs if what happens?

ventilation and perfusion of the lungs by pulmonary arteries (perfusion) match at the level of alveolar capillary interface

explain the distribution of ventilation and perfusion in the areas of the lungs when at rest.

so ventilation/perfusion is dependent upon gravity..

so our lungs are split into 3 zones where Zone 1 is the most superior and Zone 3 is the most inferior (base)

Zone 1 is going to have the most poor ventilation where Zone 3 is preferentially perfused as it is more compliant and gets more gravity.

how can we change ventilation/perfusion by repositioning a patient?

if a patient lies supine you get a better distribution from head to toe, but uneven from anterior to posterior.

what is minute ventilation?

breathing frequency x tidal volume

aka the total air inhaled or exhaled in 1 minute

what is our minute ventilation like at rest vs during exercise?

at rest your minute ventilation is 5L/min whereas during exercise it increases to 70-120 L/min

what does minute ventilation vary in accordance with?

it varies in accordance to level of PCO2

what number do we start the oxygen transport cascade at?

155mmHg which is the partial pressure of oxygen in the atmosphere

how do we get to approximately 100mmHg of oxygen from the 155mmHg?

we take a breath in, and the atmospheric air (155) mixes with our air in the trachea which is diluted with other gases (like CO2) and humidity.

the process of getting from 155mmHg to 100mmHg is dependent on what?

ventilation

so this is our breathing mechanics! how well we can pull oxygen in.

how do we get from 100mmHg to approximately 95mmHg?

we have moved atmospheric air into the alveoli (from step 1) and now we have to diffuse across the membrane to go from 100 to 95mmHg.

what affects the ability to diffuse across the membrane in the oxygen transport cascade?

- concentration gradients

- membrane permeability and thickness

- size of gases

how do we get from 95mmHg to 90 mmHg in the oxygen transport cascade?

as the air diffuses across the membrane the partial pressure drops gain and now were moving to the capillary system of the lungs.

within the capillary we mix with unoxygenated blood that is coming back from the heart reducing the partial pressure of oxygen once again!

what is the 95-90 drop in partial pressure of oxygen during the oxygen transport cascade dependent on?

ventilation and perfusion matching

how do we get from the 90 mmHg to approximately 45 mmHg?

so a few more detailed steps occur, but the big thing to note is that we move oxygen via hemoglobin to the mitochondria in the tissues.

what happens to the oxygen transport cascade during exercise?

- we increase our respiratory rate (ventilation)

so instead of going to 100mmHg from 155 we would be at a higher partial pressure of oxygen.

this idea continues down the entire cascade! so we have more oxygen to utilize.

if you hyperventilate, what happens to the oxygen cascade?

you would drop the first step in the oxygen cascade, so you would have less oxygen to utilize to the tissues.

this is where we get that dizziness symptom!

what is a normal healthy blood pressure at rest?

120/80 mmHg

what is a hypertensive blood pressure at rest?

>140mmHg/90mmHg

what is blood pressure?

an indirect measurement of pressure inside of an artery

so force exerted by blood against the vessel wall which reflects cardiac output and peripheral vascular resistance

what does mean arterial blood pressure represent?

the average force exerted by the blood against the arterial walls during the entire cardiac cycle

how do we calculate mean arterial blood pressure?

DBP + 1/3 (SBP-DBP)

OR

2/3 DBP + 1/3 (SBP)

what is the normal range of MAP?

70-110mmHg

what is a measure of the central aortic pressure and the perfusion pressure seen by the body organ?

mean arterial blood pressure

what is a MAP value where we consider "red flag" alert someone? Explain the symptoms you may see

60mmHg!

you would see dizziness, confusion, light-headedness, pale

basically they arent getting enough O2 to the brain

what is systemic vascular resistance?

this is the resistance that must be overcome to push blood though the circulatory system and create flow

what happens to blood pressure as we exercise?

you have increased blood flow during moderate exercise which increases the systolic pressure in the first few minutes and then it levels off between 140-160mmHg

does diastolic pressure change during exercise?

not really

an increase in systolic blood pressure with minimal change in diastolic blood pressure = what for the MAP?

slight increase

why does your MAP not change very much with an increase in systolic pressure? (it only slightly increases!)

because MAP is not as much systolic dependent as it is diastolic

so diastolic pressures dont change much in response to exercise

what happens with cardiac output with exercise?

it increases linearly with intensity!

in lower extremity muscles we see cardiac output values reaching what levels?

they are reaching near their maximum values close to exhaustion

in upper extremity exercises we see cardiac output values that ARE NOT reaching cardiac output maximum... why??

this is because the size of the muscle and vascular beds are so much smaller! they have higher blood flow resistance and get tired quickly. so its relative! the lower extremities are larger muscles with greater capillary beds so they can withstand more than the upper extremities can.

your arm exercises elicit a larger increase in arterial blood pressure (afterload) which increases the pressure that the heart must pump against.

why is stroke volume lower in the upper extremity when compared to lower extremity?

because of contractility, and venous return, blood volume, MAP, and neural input

what is the neural input aspect of upper vs lower extremity exercise?

there are more cortical motorneurons in the arms than the legs which may increase sympathetic activation leading to increased ventilation and blood pressure during arm exercises.

SUMMARY of upper extremity exercise? just give a little run-down.

- smaller arm muscle mass

- smaller vascular beds

these offer greater resistance to blood flow than...

- larger and more vascularized lower body muscle mass regions

sooooo

blood flow to arms requires a much larger systolic pressure accompanying increases in myocardial workload and vascular strain.

what is our % of cardiac output going to muscles at rest?

about 20%

what is our cardiac output going to the muscles during exercise?

it increases up to 80%

this is regional vascular conductance where you send blood to the tissues that need it

what does your heart rate do with intensity during exercise?

it increases until it reaches a steady state

what are the general body responses to exercise?

- increase in total body oxygen consumption

- body responds by increasing perfusion to meet metabolic demands

- body can do this by increasing cardiac output and systolic blood pressure to redirect blood flow to actively contracting tissues

why does our HR increase with exercise?

due to sympathetic stimulation at the SA node

why does our stroke volume increase with exercise?

because of the increase in sympathetic stimulation leading to an increase in contraction (inotropy)

secondarily due to increase in preload (frank starling law)

why is stroke volume blunted at higher intensities?

because we have limited filling time!!

what does exercise that is coordinated repetitive movement do for our body?

it increases venous return which increases preload and stroke volume

what is the effect of exercise on major vascular beds?

- increase flow to skeletal muscle

- increase flow to the heart

- flow to the brain remains constant

- decrease flow to kidneys and GI tract

- increased flow to skin initially to dissipate heat, but at max exercise the body will prioritize skeletal muscles and heart over thermoregulation causing decrease perfusion to skin

what are the long term effects of aerobic exercise?

HR: decreases at rest (allows for longer filling times)

SV: increases at rest (growth of ventricular wall causing stronger contractions... we see increases in filling, increases in preload, and increases in overall SV)

CO: minimal change because of an increase in stroke volume

what is our bodys response to resistance exercise?

- increase in blood pressure due to sustained muscular work compressing peripheral arterioles and increasing resistance to blood flow (afterload)

- HR increases with intensity but at a lower rate when compared to aerobics, with HR peaking at the end of sets or volitional fatigue.

what happens with our bodies during isometric contractions?

- blood flow becomes decreased in working muscles due to direct compression

- after isometric exercise you see vasodilation which causes an increased blood flow

what happens to our body with the valsalva maneuver?

you see an increase in intrathoracic pressure leading to decreased venous return and reduced cardiac output may occur.

so initial phase causes increased BP and afterload, but then the baroreceptor is stimulated and causes a decreased HR to compensate for the large increase.

what are some symptoms a person may experience after doing the valsalva maneuver?

- lightheadedness

- dizziness

due to decrease in cardiac output

is resistance training really contraindicated of those with known cardiovascular disease?

- theres really only been excessive bp elevations documented with HIGH intensity exercise but...

- generally dont see that excessive rise with low to moderate resistance training with avoidance of valsalva

what overarching response do we see post-exercise on blood pressure?

a hypotensive recovery response

explain the hypotensive recovery response.

following light to moderate exercise intensities systolic blood pressure temporarily decreases below the pre-exercise levels for up to 12 hours in normal and hypertensive individuals

what is the clinical correlate of the hypotensive recovery response?

it supports the fact that rhythmic/aerobic exercise as an important non-pharmacologic hypertension therapy

what is rate pressure product (RPP)?

this is systolic blood pressure x resting heart rate that estimates myocardial workload

basically an indirect measure of myocardial oxygen consumption (oxygen demands of heart)

what happens to RPP following endurance training?

you see a decrease in HR and systolic blood pressure for a given submaximal load, so your need for oxygen to the heart is lower, and the overall exercise capacity increases.

RPP is closely associated with what 2 things?

onset of angina and arrhythmias

any total RPP value greater than what indicates an increased risk for heart disease?

10,000

what are the 4 exercise limitations in cardiac exercise?

- arrhythmias

- Ischemia

- Cardiovascular pump failure

- Cardiovascular pump dysfunction

arrhythmias (like PACs, PVCS,) are generally not problematic unless what happens?

they are hemodynamically compromising so like (200-300bpm) causing reduced coronary and cerebral blood low causing a decreased bp, lightheadedness, syncope.

what are some things we need to do when we suspect arrhythmias with our patients during exercise?

- check patient for symptoms when irregular pulse rhythm is palpated

- measure HR for 1 FULL MINUTE

- obtain EKG to identify the arrhythmia

- document

are PVCs problematic in healthy individuals with exercise?

not really, they are more ominous in heart disease

what are the significant things we need to note with the patients that have PVCs?

- if they are hemodynamically compromising

- loss of atrial kick

- if they have 3 or more PVCs with a HR > 100 (ventricular tachycardia)

- Ventricular tachycardia can lead to V-Fib!

if PVCs decrease with exercise, what does this mean?

- suppression by a higher order pacemaker (overdrive suppression)

if PVCs increase with exercise, what does this mean?

PVCs are ischemic in origin

the foci get irritable and fire as myocardial oxygen demand outstrips the available O2 to supply it

if PVCs do not change with exercise, what does this mean?

the PVCs are unrelated to exercise

what things do we need to document when it comes to PVCs at rest?

Resting:

- count the number of resting PVCs per minute and evaluate the characteristics of the waveform (uni-multifocal, bigeminey, etc)

what do we need to document for PVCs during exercise?

- look at if another ectopic focus appears due to increase in ectopic activity with exercise induction

- terminate exercise

- refer to PCP

what is ventricular tachycardia?

3 or more PVCs at 100bpm or greater with rest or exercise

document number of complexes in a run and contact referral source (Contraindication to further exercise)

what do patients complain of with palpitations?

- fluttering

- rapid

- forceful

- irregular

a rapid palpitation may be associated with what?

a supraventricular arrhythmia

a forceful palpitation may be associated with what?

exercise

a irregular palpitation may be associated with what?

ventricular ectopy

all palpitations should be followed up with what?

an EKG

when does ischemia usually occur?

during exercise with the onset of angina, and usually relieved by rest

its when the demand for oxygen by the heart muscle outstrips the oxygen supply

what are the symptoms of ischemia?

- crushing

- squeezing

- precordial

- substernal

- short of breath