The sun has risen, and it's time for "Hey, Science," our boldly scientific weekly feature in which we have your most provocative scientific questions answered by real live scientists (or related experts). No topic is off limits in our ongoing quest for truth and time-wasting. This week, doctors explain: Why do cardio exercise when you could just do cocaine?
Today's question comes from perky Gawker reader Emma, who writes: "Why is the use of cocaine awful for cardiovascular health while running/doing some form of high-intensity exercise for 35 minutes a day ideal for heart health? Both activities raise one's heart rate to about the same BPM for similar amounts of time. Both activities temporarily raise one's blood pressure. I know there has to be a simple answer out there, but I'm not finding it and whenever I ask friends they are wont to say phrases like 'Wow. Just wow.' while looking at me as if I'm wearing a drug rug and telling them about how nobody's ever overdosed on weeeeed. Yes, I'm kind of ashamed for even wondering something so dumb, but if Gawker can't be my personal judgment free zone then what can?"
Right you are Emma! Forget your so-called friends and come party with us. But first, the experts speak:
Although they both increase the heart rate and blood pressure, exercise is beneficial in many ways that cocaine is not. The increase in blood pressure with isotonic exercise (as with running) is modest by comparison to the increase that can occur with cocaine. Furthermore the increase in heart rate and pumping action of the heart is highly regulated by the nervous system and is in tune with the metabolic demands of the body during exercise (not so with cocaine)
Whereas exercise tends to cause relaxation of the blood vessels to your muscles and heart, cocaine can cause the heart vessels to spasm. Coronary spasm reduces blood flow to the heart at the same time that the cocaine is making your heart do more work which can result in heart damage or death. Cocaine can also trigger abnormal heart beats.
Finally, whereas exercise can have favorable effects on your blood cholesterol and blood sugar, cocaine does not
I have seen young people that are regular cocaine users with coronary arteries resembling those of a sick old man, and there are famous examples of athletic young people ending up in the morgue after a noseful of cocaine.
Any questions? [Ed.: we're asking for a friend, we swear!]
Interesting question. Cocaine can intensely stimulate the sympathetic nervous system, which will elevate heart rate, but it can also stimulate release of some hormones that are bad for the heart, and inhibit some hormones that protect the heart, leading to adverse cardiovascular consequences. While exercise increases blood flow to heart due to blood vessel dilation, cocaine causes blood vessels to constrict. This effect can be severe, especially in diseased blood vessels (i.e. atherosclerosis), leading to decreased oxygen supply to the heart. Unlike exercise, cocaine can also promote blood clotting. Cocaine can decrease the heart muscle’s ability to contract and can cause abnormal heart rhythms. So, in marked contrast to exercise, cocaine can cause problems with both the blood vessels supplying the heart, as well as the heart muscle itself.
In the short run (the activity event) - Cardiac output during exercise is to meet the demand for energy and oxygen as requested by the wide range of muscles used to keep the body in motion. Thus, the body is in a position to receive the products of heightened delivery system. While cocaine use can increase cardiac activity the demand for this is not the same as in the context of the working out, thus the heightened delivery is not needed. This can pose numerous challenges to the rest of the body and heart... Thus they key is to think of cardiovascular functioning health in the broader context of the bodies response to the event - in exercise it is a coordinated response - while cocaine may stimulate a cardiac response - it is not the same when we think of it in a broader context. In addition, there are some breaking mechanisms during workouts (fatigue, be winded, etc) that allow an individual to control the stress being applied; with cocaine use this more voluntary control of the event is removed thus taxing the cardiovascular system differently. I would also suggest that the neurochemical basis for the stimulation most likely differs which could have implications for the overall cardiac functioning.
If we think of exercise over the long run, cardio exercise offers more protective factors and (mood regulation, increased endurance, lower blood pressure, improved cognitive functioning) than extended cocaine use (dopamine depletion, cardiac problems such arrthymia later in life, a potential for impaired cognitive functioning) which also is associated with lifestyle factors that can negatively impact health.
In brief, stimulant drugs and especially cocaine not only increase the work of the heart, but can have a direct toxic effect as well. Additionally they can sometimes cause the arteries of the heart to spasm, decreasing blood flow right when the heart is working harder, causing a heart attack. Finally, they are more likely than exercise to cause arrhythmias, which sometimes can be fatal.
[Send your own bizarre "Hey, Science" questions to Hamilton@Gawker.com. Image by Jim Cooke. Photo via Getty.]