SEHS Topic 2.2 Cont’d
S&F of the Cardiovascular System
Explain cardiac drift
• Cardiac Drift -
• Heart rate vs. pace for a 20-mile training run
• http://running.competitor.com/2012/03/training/the-effect-ofcardiac-drift-on-heart-rate-training_48317/3
Define the terms systolic and diastolic blood pressure
• Systolic – the force exerted by blood on arterial
walls during ventricular contraction
• Diastolic - the force exerted by blood on arterial
walls during ventricular relaxtion
Analyze systolic and diastolic blood
pressure data at rest and during exercise
Cont’d
• Determine the percent change between Resting
systolic blood pressure and sytolic blood pressure at
peak exercise for
• Group 1 – _____________% change
• Group 2 - _____________ % change
•
%change = change/original x 100
Discuss how systolic and diastolic bp respond to dynamic and
static exercise
• First things first. What’s the difference?
• Static exercise, also known as isometric, exert muscles at
high intensities without movement of the joints. Holding a
squat position, calf stretch, pushup position or plank are
examples.
Cont’d
• Dynamic exercises - These involve slow and
controlled movements through a complete range of
motion. Dynamic exercise activities keep joints and
muscles moving. Examples include full squat,
pushup, bent-over row and step-ups (moving on
and off the platform, which adds to the cardio
component).
So how does SBP respond to both?
Why? – Dynamic:
• During cardiovascular exercise such as running,
swimming and cycling, normal blood pressure responds
with an increase in SBP (increased C.O. due to gas and
nutrient demands by the exercising (cells engaged in
respiration) tissues. There is no change or slight
decrease in DBP.
• Blood pressure response is proportional to the overall
exercise intensity. In other words, as exercise intensity
gradually increases, SBP gradually increases. Although
maximal heart rates are comparable for men and
women during maximal exercise, men generally have a
higher SBP.
Why? – Static:
• In contrast to cardio exercise, there is a
disproportionately high blood pressure response to
more static exercises. During isometric exercise, where
the muscle is contracted but there is no change in
muscle length, both SBP and DBP can increase
substantially even at only 30percent maximal effort.
• An example of an isometric muscle contraction is a
sustained handgrip or a sustained pull-up arm hang.
Isometric exercises aren't recommended for those with
heart conditions.
•
Why? – Static cont’d
• In addition, heavy resistance exercises involving
movement of the muscle can cause extreme blood
pressure responses. A study measuring arterial
blood pressure response to heavy resistance in
bodybuilders reported blood pressure responses
for 95 percent to 100 percent maximal effort
during a biceps curl, single leg press and a double
leg press. Both SBP and DBP elevated, with average
values exceeding 320/250mmHg for the double leg
press.
The elevation in pressure was believed to be due to
the compression of the arteries by the muscles, and
holding of breath. Researchers recommend that the
length of the lifting set is the main factor in affecting
blood pressure response.
Compare the distribution of blood at rest and
the redistribution of blood during exercise
• Bottom line – there is a shunting of blood to the
skeletal musculature during exercise
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Describe the cardiovascular adaptations resulting from
endurance exercise training
Increase to the left ventricular volume, which equates to?:
Increase in SV
Lower resting and exercising HR
Increase in blood flow leads which leads to an increase in O2 to
the working muscles. An increase in O2 transport to the working
muscles enables your muscles to exercise longer before
fatiguing.
• Endurance training can induce growth of new blood vessels
(angiogenesis), but the effect is dependent of the type and
intensity of training. An increased capillarization has been
observed in training studies performed at 70–80% of V˙O2max
(Andersen & Henriksson, 1977); whereas training at an
intensity of 45% of V˙O2max has been shown to have no effect on
capillarization (Denis et al. 1986)
Explain maximal oxygen consumption
• Also known as VO2 max represents the functional
capacity of the body to transport and use oxygen .
It may also be described as your body’s maximal
aerobic capacity.
• VO2 max can be expressed
either as an absolute rate in
liters of oxygen per minute
(l/min) or as a relative rate in
millilitres of oxygen per kilogram
of bodyweight per minute (ml/kg/min).
Cont’d – What the gas-analyzer
determines:
Discuss the variability of maximal oxygen consumption in
different groups
• Absolute values of VO2 max are typically 40-60% higher
in men than in women.
• Obviously, this difference is most notably due to the
variance in bodyweight and lean body mass between
men and women. A more accurate comparison of
maximal oxygen uptake between men and women
would use the relative measure.
• Research has shown that the average young untrained
male will have a VO2 max of approximately 3.5
litres/minute (absolute) and 45 ml/kg/min (relative).
• The average young untrained female will score a VO2
max of approximately 2.0 litres/minute and 38
ml/kg/min.
Cont’d
Here are some more relative VO2 max
scores (measured in ml/kg/min) for men
and women:
Males
Females
Cross-country skiiers
84
72
Distance runners
83
62
Sedentary: young
45
38
Sedentary: middle-aged
35
30
Post heart attack patients
22
18
Severe pulmonary disease patients
13
13
Discuss the variability of maximal oxygen
consumption with different modes of
exercise
• http://www.sport-fitnessadvisor.com/VO2max.html
Cont’d
• Oxygen uptake is important when exercising,
especially for people who are training for a specific
event or trying to lose weight.
• A sufficient oxygen supply helps to increase
performance, prevent dizziness and raise fatburning potential.
• Sprint interval training helps to increase EPOC, or
excess post-exercise oxygen consumption, which
helps to dramatically accelerate results, according
to San Diego State University.
• While jogging also can increase oxygen uptake
somewhat, it does not do so nearly as much as
interval training