system
Given the following post, respond as if you're commenting on Reddit:
human
Is it possible to strengthen the muscles in your body that you don't have conscious control over?

I realise there are some muscles in your body that you have *indirect* conscious control over like your heart muscles (aerobic exercise = heart workout). I'm not talking about those.

Is there any muscles in the body that you have no conscious control over, direct or indirect (For example, muscles involved in digestion and other internal processes)? Can these muscles be strengthened with steroids, electric pulses ect.?
gpt
The short answer is yes.

First of all there's diet. Improper diet will reduce muscle mass and if you return to a normal diet, the musculature will be able to adapt to "normal" daily activities even without additional exercise. 

Second, there's exercise. Even tho you might not have the mental control to lets say flex or pull that muscle individually, it is still capable of performing work like bearing a load. Like the prior point, muscles will stop adapting once they're adapted. Add work and they will have a new requirement beyond normal daily ruitines to adapt to. 

The muscles we have good mental control over are muscles that create motion. This is because we have trained our capabilities to move these exact muscles. And most of the time we don't control these well as single muscle, but more so as a muscle group. Like how most of us can only possess the control to flex our abs as one muscle group because all the individual muscles serve more or less the same motion and purpose.

Most muscles play supportive and stabilizing roles, and with training we should be able to single them out from the group. Or atleast single out smaller groups from a larger group. Like how some people can "roll" their stomach. This is because they have achieved the neurological control of down to two abdominal muscles at the time. 

However, we are able to activate these supportive muscles even without having mental control over them.  We do this by performing a task in which they are needed. Infact, this is probably a necessary step if you want increased mental control over them. (But then you must try to remove segments from a task or a motion which requires other muscle(groups) too untill you've isolated the desired muscle(s).) If you do an exercise like the plank, you will activate many such muscles. They will bear a load and perform work, which again gives them something to adapt to.  The same thing goes when you do other full body exercises. 

The "Kegel exercise" for women is often explained by "stopping your urinal flow". This is a motion, or activity, that you know how to do. If you do it a few times while peeing you'll soon learn to control, atleast the group as a whole, whenever you decide to, allowing you to exercise it. 

This even goes for your heart, which is a muscle. You probably cant take mental control over your heart. You cant suicide by deciding that it should shut down. Most of us cant even make it slow down when we're confronted with a cute person of the opposite sex even as it creates awkward situations. But like above, you can do things to make it change. You can think of things that makes it work slower or faster, or do activities which requires it to do more work. It might even make you capable of taking better control over it, perhaps calming it down in stressful or scary situations.
As for strength of the hearth, more work will make it adapt, making it capable of pumping faster, pumping harder(more amount of blood per stroke) and so forth, or in other words; becoming stronger, even without ever having had mental control over it. 

Third, there is medicaments, which can cause more work or greater adaptation than normal for the amount of work. Perhaps the biggest problem with anabolic steroids is that the heart too becomes bigger and thicker and therefor clusters up. This is why so many athletes using anabolic steroids, particulary those in high intensity sports, which puts work on the heart, drops dead from heart problems not long after turning 40. 
Stimulants puts more work on the heart, and many of the more extreme ones, like amphetamine and efedrin,  are highly connected to hearth problems also.