Why is Increasing My Heart Rate with Exercise Good, but Medication/Narcotics Bad?

Everything in medicine has its risks and benefits, and must be weighed.

Narcotics (opiates) do not typically increase the heart rate, but drugs like cocaine and meth do, as they cause a sympathetic surge (adrenaline rush). Regarding cocaine, it not only causes an increased heart rate but it can cause your coronary arteries (the blood vessels to your heart) to constrict (squeeze), resulting in heart attacks due to not enough blood and oxygen getting to the cardiac tissue. Additionally, cocaine has been shown to accelerate the process of atherosclerosis (plaque build-up inside arteries) which can lead to heart attacks as well. In other words, you can make your 20 year old arteries look like those of a 60 year old.  Additionally, with this surge comes an elevation in blood pressure, which can cause things like intracranial bleeding (head bleeds), aortic dissections (tears) and other not so fun things.

The temporary elevation that exercise provides is okay, to a degree, but you’re increasing your heart rate. In healthy individuals, blood pressure (BP) should increase with increasing exercise intensity, with most of that change coming in systolic BP. Diastolic BP, in healthy individuals, will stay the same or slightly increase (increases or decreases of diastolic BP of 10 mm Hg or more is criteria for terminating exercise). Lack of systolic response to increasing intensity can be a reason to stop grade exercise testing (beta blockers can affect BP responses, blunting them in testing). During steady state exercise, systolic BP will increase to a point and then plateau, but should still increase from resting levels.

Exercise does not result in the arterial constriction that we see in cocaine users. With consistent exercise, your resting heart rate will decrease as the heart molds itself and becomes more efficient. Your heart is essentially strengthened as a result of exercise, so it needs to beat less frequently.  You can see the difference in cadavers – large hearts generally indicates the person was a runner.

These are no substitute for exercise as the myriad of elements that constitute exercise involve multiple other hormones and bio-chemicals released and involve other processes such as peripheral vasodilation and visceral vasoconstriction.  Using these medications to “exercise” your heart will not improve your conditioning and in fact, if used over a long period of time, increase your mortality.

An increase in heart rate due to anxiety is a trigger from your sympathetic nervous system. This is the “fight or flight” side of the nervous system that can be triggered from stress, pain, anxiety, etc. The triggering of this reaction also causes an increase in BP, among other things.

If your BP and heart rate are frequently increased from this, it can lead to an increased risk for heart disease, heart failure, stroke, and atherosclerosis. Don’t worry about it too much, though. There are a couple of things that you can do to counteract these things:

  1. Exercise
  2. Watch sodium intake – sodium makes you store less water on your body causing the total amount of blood to decrease, therefore lowering blood pressure.

Fun fact: During the time you exercise you are at much greater risk of sudden cardiac death (heart stopping), myocardial infarction (MI, AKA heart attack), arrhythmia (abnormal rhythms of the heart), and stroke. But the time after you exercise, you get a decrease in your overall cardiovascular mortality (death) and morbidity (sickness) that more than compensates for the increased mortality of exercise.

TLDR: Narcotics are not the issue, but drugs like cocaine will make your heart weaker along with all the other bad stuff drugs can do.