I'm 28, have been running for 10 years (up to 6 miles/day), and 3.5 years ago I got my script for Adderall. If anything, it was like I couldn't STOP running when I took the meds. What used to be a 3-4 mile run turned into 7-8 miles.
At first, that may sound like over-exertion and hard on the heart. However, I was already in shape when I started taking the Adderall so I never have had a problem exercising while dosed.
Moreover, I would argue that you specifically should exercise more when taking Adderall for 3 reasons:
1) Adderall increases your BP (about 10-15 points for me), and if taken over a long period of time can have serious consequences on your heart. Running decreases BP and it's a very noticeable difference. My BP is generally 120-130/70-80 when I'm on the Adderall, which is within a controllable and safe range. I stopped running for 6 months one time and my BP was consistently 130-140+ while dosed.
2) I'm sure someone will correct me if I'm wrong, but I believe Adderall decreases your dopamine levels which can lead to depression and anxiety. Exercising helps restore dopamine levels.
3) Running helps to deplete excess energy and regulate serotonin levels (again, correct me if I'm wrong). This helps to decrease the chance of amphetamine psychosis and restore appetite. When I take Adderall for several days in a row without running, I'll notice an increasing tensity in my muscles that has led to panic attacks. A quick run has always cured this for me completely.
Ok so I'm not a doctor or pharmacist, so this is just my understanding from doing research and talking to a handful of doctors since receiving my script. I am, however, an engineer and even if I got the terminology wrong, the mechanisms of action make scientific sense.