Children who are diagnosed with ADHD may have to deal with hyperactivity. These children grow into adults. While some adults with ADHD learn to control their hyperactivity and restlessness, others still struggle with this symptom.
Hyperactivity or restlessness is a hallmark symptom for some adults with ADHD. These adults literally feel the need for speed racing a car, either on a racetrack or down the freeway to help them relax and clear all extraneous thoughts out of their minds.
As one patient responded on the MedicineNet website (page two), “Relaxing at 110 mph – that should have been a clue.” This patient said his mind is always “frantically going and going.” Before he received his diagnosis of ADHD, he thought everyone experienced racing thoughts. This patient cannot sit still for more than 10 minutes at any one time–he feels the need to get up and move.
Another patient, in her mid-40s, likened her feelings of hyperactivity to feeling “like the Energizer bunny.” (Page three) 
Yet a third patient, a nurse, used to joke with colleagues that she was unable to sit quietly long enough to work on patient charts and write care plans for each patient. While her need to be moving made her a favorite among nurse’s aides, she was not able to complete required paperwork on each patient.
After she changed nursing jobs to a new position that required her to sit for long periods of time, she realized her inability to concentrate was related to her need to move. After she took an online quiz about ADHD, she spoke to her doctor and received an official diagnosis of adult ADHD. (Page three) 
Under the hyperactivity, an entire constellation of symptoms includes racing thoughts, feelings of agitation, and internal restlessness, getting easily bored, risk-taking, multi-tasking, fidgeting and inability to sit still, excessive talking, and craving for excitement, states Helpguide. 
Some of the same treatments for children with ADHD also work well for treating hyperactivity in adults. These include Dexedrine, Ritalin, Focalin, Concerta, Adderall, and Vyvanse. Treating an adult with ADHD with a stimulant medication comes with drawbacks because some of these adults have developed substance abuse problems. Stimulants are controlled substances–Schedule II. These same adults may forget to take the medication at the right time, which is a problem when the adult is on a prescription that requires taking a pill more than once a day. In addition, some stimulants are short-acting and wear off quickly. In seeking a way of relaxing, these adults may be tempted to self-medicate with other substances, states WebMD.
A non-stimulant medication like Stratterra has little to no abuse potential and requires no special prescription. This is the only medication, thus far, to receive approval from the Food and Drug Administration, for treatment of ADHD in adults. 
ADHD doesn’t miraculously end or “get cured” when the child grows into adulthood. Instead, the adult continues to feel symptoms, one of which is hyperactivity.
The adult with ADHD continues to need medical and psychological intervention to deal with hyperactivity and related symptoms/behavior. While stimulant medication may offer short-term help, it comes with risks. The adult has another option in the FDA-approved non-stimulant medication–Stratterra.
 Patient Discussions: Adult ADHD (Attention Deficit Hyperactivity Disorder: - Symptoms Experienced. MedicineNet, retrieved at https://www.medicinenet.com/adhd_in_adults/article.htm
 Attention Deficit Hyperactivity Disorder: ADHD in Adults. WebMD, retrieved at https://www.webmd.com/add-adhd/guide/adhd-adults?page=2
 Melinda Smith, M.A. and Jocelyn Block, M.A. Adult ADD/ADHD: Signs, Symptoms, Effects, and Treatment. Helpguide, retrieved at https://helpguide.org/mental/adhd_add_adult_symptoms.htm