Why is a rapid heartbeat and high blood pressure from exercise healthy for your cardio system, but the same effects from drugs like alcohol and nicotine cause damage?
In: Biology
The fundamental difference lies in HOW the blood pressure and heart rate is raised.
Rapid heartbeat and high BP which occur during exercise is a physiological phenomenon, a normal body reaction to physical stress. Exercise, especially cardio, is a practise for the heart and blood vessels at pumping blood. It’s like doing practice sets of exams over and over again so that at the end of your practice you’re capable to ace anything thrown at you. Exercising trains your cardiovascular system at pumping blood efficiently under stress (the heart gets better at pumping blood and the arteries become more compliant), so that under normal condition, it becomes a walk in the park. This why you see bradycardia (lowered heart rates) and physiological hypertrophy (non-disease caused increase in size) of the heart in endurance athletes.
What happens due to smoking and alcohol is pretty insidious. Smoking releases carbon monoxide and other chemicals into the blood and alcohol disturbs many enzymatic processes and directly harms the liver, which is the body’s main protein and important chemicals factory. This precipitates many pathological processes which essentially ends up in the heart pumping blood harder against a non-compliant blood vessel system. Which means that the heart is pumping against a high peripheral resistance pathway (narrowed arteries) without much avail. This leads to enlargement of the heart to compensate for the narrowed blood vessels (pathological hypertrophy) but since the blood vessels supplying the heart are still non-compliant and insufficient, the heart ultimately fails.
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