Health - Amphetamines and exercise

[Moonage Daydream]

Sometimes, but by no means every time, SWIM goes to the gym after doing a few lines. She does not do this immediately afterwards, usually allowing an hour as if digesting food. Swim is worried about the strain on her heart, so she deliberately goes for a relatively gentle workout rather than pushing her body further than it could go naturally which can be tempting. Swim finds that exercise helps her relax and sleep better whether on speed or not.
She used to dance for eight hours on speed without worrying about her heart but she worries now because in relative terms she is more sensible.
Should swim worry if she is careful in this way, within the limits of her controlled, but none the less habitual, use of amphetamine?
By the way swim eats normally on speed days as well (ie 2 or 3 times) just a bit less than on the 2 or 3 days per week on which she forces herself to do without. This means that she replenishes energy used with the trusty old "emergency bananas" and dried fruit etc...