SEHS Topic 2.2 Cont’dS&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-of-cardiac-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

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 fat-burning 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