Sports medicine pt.2

Question 1

How does the body produce energy?

Answer 1

Through the formation of ATP from ADP+phosphate, main source of energy and storage being glycogen and fats, which are activated to produce ATP

Question 2

What source is used for ATP production?

Answer 2

Depends on the situation :
- ATP and Phosphocreatine in muscles are used in maximal power short-lasting activities, lasting only 6-8 seconds
- Anaerobic glycolysis which is activated after phosphocreatine storage is depleted, and is represented by the lactic anaerobic system, it lasts 40-60 seconds, as it is fast but no so efficient since glycolysis is not so good in anaerobic situations; this will lead to
production of lactic acid and, as a consequence, pain in muscles – even if the pain is in reality due to
the fact that lactic acid is a weak acid and with time free hydrogen accumulates giving tissue acidosis and so pain
- Aerobic glycolysis: Limited power long lasting energy (minutes to hours) is provided by fats, through beta oxidations and glycogen, through aerobic glycolysis (dependent on oxygen) and; it is very
long lasting but has limited power: the typical examples of use of this energy are during marathons or cycling races.

Question 3

How much glycogen is stored in the body?

Answer 3

About 500g (400g in muscles and 100g in liver)

Question 4

What is the anaerobic treshold?

Answer 4

• The point where the body switches from anaerobic to aerobic glycolysis
• The exercise intensity where the muscles start to use anaerobic glycolysis
• The exercise intensity when the balance of production and removal of blood lactate is equal.

Question 5

What is the waste product of anaerobic glycolysis?

Answer 5

Lactate and hydrogen ions

Question 6

What happens during lactate production in anaerobic glycolysis

Answer 6

• Lactate production at the end of anaerobic glycolysis is
  not alone but with hydrogen ions
• So you start to accumulate hydrogen ions which is being buffered by
  bicarbonate. When you use bicarbonate in your body, you develop metabolic acidosis
• At maximum exercise you start to develop metabolic acidosis. So the real reason you feel pain and start
  wheezing like hell and need to stop is because of metabolic acidosis and this is the anaerobic threshold.
• Don’t think that this is because of lactate since it is a weak acid, it is because of hydrogen ions being
  buffered by bicarbonate (HCO3)
• However blood lactate is a good thing to measure to see if your body is
  going into metabolic acidosis

Question 7

What are ways to measure lactate?

Answer 7

Two different ways:-
Direct- taking a blood sample.
- Indirect methods use derived parameters to find the same concept. You don’t directly measure lactate but
you look for other parameters that can suggest to you where the anaerobic threshold happens. You can use
respiratory gases or heart rate. You can do an analysis with face masks with oxygen inspired and CO2
expired.

Question 8

How does our body increase O2 supply during exercise?

Answer 8

1.By increasing blood flow to muscles (main mechanism): from 3 to 70-75 ml x 100 g of muscle/minute (20-25 folds increase of blood flow to muscles);
2- 2-3 fold increase in O2 extraction from the blood (O_2A-V difference goes from 5 to 13 ml x 100ml of blood)

Question 9

What type of CV changes are seen during exercise?

Answer 9

2 types: Acute and chronic
- the more active CV changes are
stimulated the more the CV system tries to adapt and be more efficient, leading to chronic CV changes that
will allow us to be more fit.
- All these mechanisms give you the chance to achieve maximal performance in the acute phase of the
exercise.

Question 10

Maximum heart rate calculation

Answer 10

• Theoretical max heart rate= 220-age in years (formula most simple and used in the clinic)
• Another formula is Tanaka formula: 208 – 0.7 x age in year; it is more efficient for extreme ages
  (very young or very old pts)

Question 11

What is cardiac output determined by?

Answer 11

Stroke volume and heart rate

Question 12

How does heart rate, stroke volume, and cardiac ouput differ between sedentary people and athletes?

Answer 12

• In sedentary people, the HR can raise about 3-fold when they exercise. The SV on other hand increases just a little. In the end, the CO increases just by 3-4-
  fold..
• In athletes the numbers are different; The HR is lower and the SV are much
  higher at rest. This happens since they have bigger hearts and so bigger SV, reaching the same CO at rest
  with fewer beats
• During exercise, their HR and SV
  increase a lot, giving rise to an almost doubled CO respect to sedentary people after exercise.

Question 13

Which variable, sv or hr, affects cardiac output more in sedentary vs activity CO?

Answer 13

HR since it increases much higher than sv

Question 14

What are conditioning factors?

Answer 14

These are the factors that are most relevant to determine the impact of a physical activity on the body, more
specifically the CV system:
* Intensity (energetic demand)
* Kind of exercise (endurance, isometric, …)
* Posture, involved limbs, …
* Psychological factors;
* Environment (altitude, depth, temperature, humidity …)

Question 15

How can intensity of exercise be measured?

Answer 15

It can be measured by calculating MET (Metabolic Equivalence of Tasks)

Question 16

What is a MET?

Answer 16

1 MET stands for the energy used in resting conditions, and MET values
of different sports can be seen on the chart (Golf 4.5 METs, etc)
- It can be expressed as a direct indicator of O2 consumption

Question 17

O2 consumption at rest

Answer 17

At rest every kg of a person uptakes 3.5 ml of oxygen per minute. 3.5ml x kg/min

Question 18

What can the kind of exercise be divided into?

Answer 18

Through studies, scientists established classifications on all sports based on their effect on the body. These
are;
- Power/Explosive Strength activities,
- Mainly Anaerobic Activities (short, brief, strenuous)
- Mixed Aerobic/Anaerobic Activities (short, max involvement of both metabolisms)
- Mainly Aerobic Activities (endurance)
- Dexterity/Skill Activities (posture, neuromuscular coordination)
We can also divide exercise into isotonic and isometric exercies

Question 19

Describe CV effects of skill/dexterity activities

Answer 19

• CV involvement is minimum.
• Chronic Heart changes are poor, increase of volume and of myocardial mass are minimal and are
  similar to sedentary subjects.

Question 20

Describe CV effects of power activities

Answer 20

• Typical chronic heart changes are not much increase in heart volume and huge increase of myocardial mass.
• Weightlifting, alpine skiing, and surfing are some of the sports that fall into this class.

Question 21

Describe CV effects of mixed activities

Answer 21

• Mainly compromised by a variety of team sports like football or water polo.
• Of course, the CV involvement is not the same in football as it is in volleyball but generally, they are all classified by variable changes in peripheral vascular resistance and cardiac output.
• During a match, HR, PVR and CO vary a lot and in the chronic setting the CV changes for heart volume and myocardial mass vary for each sport.

Question 22

Describe CV effects of aerobic/endurance activities

Answer 22

• CV changes include a high increase of heart volumes and a moderate increase in myocardial mass.
• In this class we have long distance running, triathlons, and rowing. Cycling is included in the mixed
  section rather than this one because there are both aerobic and anaerobic elements present.

Question 23

Isotonic exercises vs isometric exercises discription

Answer 23

• Isotonic exercises are dynamic, they imply movement of articulations, while isometric exercises do not imply movement of articulations
• More simply, isotonic means that during the exercise there is a continuous change of muscle fibre length, whereas the force stays regular. Isometric on the other hand is when the muscle fibre length is stable when the force applied changes
• We classify dynamic isotonic exercises as endurance exercises that are performed for a long time over long distances, on the other hand weightlifting is an isometric exercise.

Question 24

What is VO2 max related to?

Answer 24

Directly related to oxygen and cardiac output

Question 25

short duration Aerobic exercises cardiovascular changes

Answer 25

• At the beginning of the activity,
  stroke volume (SV) and heart rate
  (HR) increase leading to a increase in
  cardiac output (CO)
• After the rise at the beginning, they all remain constant during the exercise.
• Systolic blood pressure (SBP) rises
  at the beginning like the SV and HR
  and then remains constant.
  = Diastolic blood pressure (DBP)
  does not change in these kinds of
  activities.
• Mean arterial pressure (MAP) can
  only increase at the beginning then
  stays the same.

Question 26

long duration Aerobic exercises cardiovascular changes

Answer 26

There is a phenomenon known as
Heart Rate Drift- it happens when the
exercise is pushed beyond the
anaerobic threshold.
It is also called the cardiovascular drift,
and it is the progressive increase in HR
and decrease in SV that begins after
approximately 10 min of prolonged
moderate- intensity exercise. It is also
associated with decreased maximal
oxygen uptake, particularly during heat
stress. – ncbi
The decrease in SV is little since the
target is to maintain constant CO. SBP
increases then remains constant and at
the end decreases. MAP and DBP
remains constant

Question 27

Diastolic blood pressure value in isotonic aerobic exercises

Answer 27

In isotonic aerobic exercise, diastolic blood pressure does not rise. Mean arterial pressure rises because systolic blood pressure rises.

Question 28

How can Isotonic dynamic exercise be looked at

Answer 28

Isotonic dynamic exercise can be defined as volume work, because the cardiovascular system adapts by trying to increase the preload and to decrease the afterload

Question 29

isotonic incremental exercises cardiovascular changes

Answer 29

• It means increasing the workload until x2
• There is a simultaneous increase in the HR until maximum and the SV increases at the beginning and then reaches a plateau.
• At the maximal intensities, CO relies mainly on the rise of HR
• Stroke volume is relevant around 50% of the maximal intensity.
• In this case SBP increases significantly, DBP does not change.

Question 30

dynamic (isotonic, aerobic) exercises cardiovascular changes

Answer 30

• HR increase related to intensity,
• MBP increases slightly,
• Vascular resistance decreases mainly by vasodilation.
• Venous return increase, mainly by squeezing of veins.
  = Myocardial O2 uptake rise is proportional to the increase of SV and CO.

Question 31

Static isometric exercise cardiovascular changes

Answer 31

• In isometric exercise the main aspect is the power expression of exercise
• The first row is the cardiac output. MVC stands for maximum voluntary contraction. From left to right there is an increase in MVC and the intensity of the exercise increases in terms of force and strength.
• The second row is the stroke volume, the third row is the heart rate.
• Increasing MVC means increasing the HR, but SV decreases during exercise with high intensity.
• In isometric exercise, also known as static exercise the venous return decreases slightly and vascular resistance, which is the peripheral arterial resistance increases with vasoconstriction.
  MAP also increases.
• HR increases only due to adrenergic stimulation, and this is the main difference between isometric and isotonic exercise. This is called pressure work and it implies an increase in peripheral vascular resistance
• In static exercise, myocardial oxygen uptake increases but this increase is not proportional to the amount of increased stroke volume and
  cardiac output.

Question 32

Blood pressure in high intensity isometric exercises

Answer 32

Mean blood pressure increases drastically during high intensity isometric exercise

Question 33

Effect of exercise location on BP

Answer 33

• BP increases more with lower body exercises (e.g. leg press vs biceps)
• This is because muscle mass
  in superior limbs is lower than that
  of inferior limbs.

Question 34

What does the amount of pressure work depend on?

Answer 34

• Intensity of exercise (% of 1 muscle repetition, MR)
• Amount of muscular mass involved
• Time of contraction

Question 35

Exercise changes in a patient with hypertension

Answer 35

For a patient with hypertension that likes to workout in gym, we need to decrease pressure load on the heart. For this reason, correct exercise prescription is very important.
A lower pressure load on the cardiovascular system can be reached with:
- Lower intensities of work (max 30-50% of 1MR)
- Smaller muscular masses involved- less muscles are working at the same time
- Shorter time of contraction (1-3 sec.)
- Longer recovery time between series (at least 2 minutes)