Sports medicine pt.3 Flashcards
Dynamic vs static exercise CV change
- Dynamic exercise vs. Static exercise
In dynamic exercise (isotonic, aerobic), heart rate increases tremendously, while the mean blood pressure is always the same. - In static exercise (isometric, anaerobic), heart rate and mean blood pressure increases.
How is such high increase in cardiac output seen in exercise?
Because of the phenomenon of the
redistribution of the cardiac output. Blood flow to the different organs can be regulated according to the body district involved during exercise.
- At rest, blood mainly flows to GI system and 15- 20% goes to the muscles and kidneys
- However, when exercise, 80-85% of blood goes to muscles
- Proportion (4-5%) of blood going to the heart is the same, but the amount changes
Psychological factor and cv changes
In neurogeneic sport activities (intense activities, F1 and skyjumping) heart rate increases in critical moments from adrenaline
Altitudes effect on body
- High altitude (hyperbarism)- when you are higher from the sea level, there is a
progressive reduction of barometric pressure and oxygen partial pressure that can lead to hypoxia - Around 800m, O2 saturation of the arterial blood goes down to 65% and the
peak aerobic power goes under 25%. - Hypoxia in high altitude can cause high altitude cerebral edema (HACE). This can
occur after body is exposed to a low- oxygen environment and before it acclimatizes. When you change altitudes without waiting for a certain amount of time (acclimatization) HACE can happen. It is a severe and potentially fatal condition. It can be seen in altitudes
higher than 3000m. It is characterized by ataxia, fatigue and altered mental status.-
Depth effect on body
Same mechanism as high altitude leads to hypoxia
What is the effect of dehydration on CV
Increase in heart rate
What is the diving reflex?
An ancestral reflex where contact with cold water, especially the face, causes bradycardia
Heat effect on CV
Heart rate increase when the temperature increases, even when at rest, fever leads to increase in HR
What is chronic cv change?
Chronic CV changes are physiological changes of both structure and function of the heart and vessels, induced
by a regular training : Athlete’s heart.
What can chronic cv changes be divided into?
There are 2 types of CV changes of chronic adaptation:
- Central changes (heart)
- Peripheral changes (blood vessels
What are central cv changes in chronic exercise?
- Increased heart volume (higher stroke volume)
- Lower heart rate (both at rest and at submaximal working loads
The heart grows in dimension, athletes have bigger and more efficient hearts, with normal systolic and diastolic function, called Athletes’s cardiomegaly, hypertrophy
HR of blue whale
In nature the blue whale has the biggest heart: 180 kg, with a SV of 220L. it
has indeed an HR of 8 or 10 beats per minute
What does enlargement of the heart in athletes depend on?
There’re physiological limits for the enlargement of the heart in the athletes and they depend on:
- Body size of the animal
- Muscular energy demands: the size of the heart depends on the size of muscular mass involved during
activities
Which animal has the smallest heart to body weight ratio?
Humans
Type of heart growth in power cs endurance athletes
In endurance athletes (like cross
country runners), the heart was characterized by eccentric hypertrophy with big cavity and moderate
hypertrophy of LV walls while in power athletes (weight lifters) it was characterized by a concentric
hypertrophy with similar cavities to the one of sedentary people but with a considerably thicker LV
wall.
Characteristics of heart enlargement in athletes heart vs pathological conditions
- Athlete’s heart becomes larger
harmoniously, bilaterally, symmetrically and involving all the chambers. - Most pathological conditions did
not have this symmetry like in hypertrophic cardiomyopathy
(affecting mainly the LV), dilated cardiomyopathy (LV) and
arrhythmogenic cardiomyopathy (affecting primarily but not
exclusively the RV).
The symmetry is an important
Cardiac hypertrophy in white vs black athletes
Black athletes have more cardiac hypertrophy than the white athletes, making them more efficient
LV diastolic diamter and left ventricular thickness values in athletes
- The upper limit of the LV diastolic
diameter is 63mm, while most adult male athletes have 58-59mm, but we can also see some extreme cases up to 70mm. - For the hypertrophy, the limit for the LV
wall thickness at 13mm even if there can be cases of extreme hypertrophy with values reaching up to 16mm especially in athletes practicing sports that require a very high
energy. - In junior athletes: These limits are
lower in junior athletes even if they are also highly trained. The limit for the LV
diastolic diameter is 60mm, and 64mm can be seen in some rare cases. For LV wall thickness the limit is 12mm and there are rare cases of 14mm.
Most CV diseases in the young that don’t allow them to do sports
In italy, Most of our diseases, CV diseases in the young, have an arrhythmic risk problem. They do not die
from heart rupture but from arrhythmia
How do GPs make money in Italy?
every GP takes the money based on the number of assigned pt, independently on whether they come to the clinic or not
What is the top cause of sudden cardiac death in the USA?
Hypertrophic cardiomyopathy is the first cause of SD in athletes in the US.
What can the Causes of sudden death in athletes be divided into
SD in athletes during sports is mainly due to 2 reasons:
* Arrhythmic death: usually due to ventricular tachycardia that leads to ventricular fibrillation
and finally results in death
* Mechanical death: mainly aortic rupture
Sudden death from impact to chest
- Commotio cordis is a phenomenon in which a sudden blunt impact to the chest causes sudden death in the absence of cardiac damage.
- Resuscitation, once thought to be nearly universally unsuccessful, has now been demonstrated to be successful in up to 35% of commotio cordis victims.
- The initial rhythm is ventricular fibrillation in those in whom a defibrillator is used relatively early
after the event. Currently, the outcome of resuscitation in commotio cordis appears to be very similar to that for resuscitation in other forms of sudden cardiac death. - Commotio cordis is a primary arrhythmic event that occurs when the
mechanical energy that is generated is confined to a small area of the
precordium and profoundly alters the electrical stability of the
myocardium, resulting in ventricular fibrillation. It is usually, although not invariably, fatal. In only about 25% (1/4) of cases (internet says 35%), cardiopulmonary resuscitation, or
defibrillation results in survival - a low percentage, considering that commotion cordis is defined by the absence of structural heart disease.
