Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by enduring difficulties with inattention, hyperactivity, and/or impulsivity that cause problems in different areas of life (NIH, 2023). It is a relatively common psychological disorder, with prevalence estimated to be around 2-4%. Even so, according to a National Comorbidity Survey Replication in the United States, only 11% of adults with ADHD were receiving treatment as of 2006 (Kessler et al., 2006). While treatment most often includes medication, therapy, or coaching focused on improving skills, alternative approaches such as dietary supplementation, meditation, and physical exercise also show promise.
Exercise has been shown to benefit individuals suffering from a wide variety of psychological disorders and concerns (Carl, Mason, Smits, & Asmundson, 2021). Meanwhile, the fact that exercise has innumerable other health benefits, is generally low-risk, and can be very affordable and accessible to most people, make it a highly attractive intervention option.
So, what is the evidence for exercise as an intervention for ADHD? A number of clinical trials have taken a look.
Trials in children and adolescents
Much of the research in exercise for ADHD has focused on changes in executive functioning. Executive functions are cognitive functions that support self-monitored and self-regulated goal-directed behavior (Gioia et al., 2001). In people with ADHD, working memory (the part of memory that holds things in mind for a short period of time), response inhibition (the ability to wait and consider options before responding), cognitive flexibility (the ability to switch between thinking about two different concepts), risk taking, and planning are often operating at less than ideal levels. These executive functions contribute to the difficulties in attention, hyperactivity and impulsivity in ADHD.
A review of experiments found that immediately following physical exercise, children with ADHD showed improvements in a number of executive functions (response inhibition, cognitive control, attention allocation, cognitive flexibility, processing speed, and vigilance; Den Heijer et al., 2017). Academic performance in reading comprehension and arithmetic were also found to be improved in both children with and without ADHD following physical exercise. However, not all assessed aspects of academic and cognitive functioning responded to exercise, including verbal short-term and working memory. Another study reported that parents and teachers found children with ADHD overall showed improvements in class behavior after physical activity (e.g., diminished interruption and unintentional aggression), although there weren't changes to intentional aggression, language use and following directions.
In addition to looking at effects immediately following exercise, some studies have looked at effects of “chronic,” or regular exercise in children with ADHD. Cardio exercise has also been linked to longer lasting effects on cognition in children with ADHD, resulting in improved attention, response inhibition, planning, verbal working memory, and cognitive speed (Den Heijer et al., 2017). Some uncertainty about how helpful exercise might be in the long-term exercise can be inferred by some studies not reporting more significant beneficial long-term effects in areas like inhibition, processing speed, planning, and memory span (which suggests null findings); however, lack of agreement in findings might partly be explained by the small sample sizes.
Overall functioning, general ADHD symptomatology, attention, self-esteem, anxiety, depression, somatic complaints, academic and classroom behavior, and social behavior were reported to be improved after regular cardio exercise in this review, extending beyond the day on which the physical exercise took place.
Trials in adults
For adults with ADHD, the research is scarcer, but is picking up recently. The same review reported that in the available studies, adults had improved cognitive and behavioral functions including attention, inhibition, motivation, and impulsivity immediately after exercise (Den Heijer et al., 2017) Just as in children, not all tested executive functions improved, but the fact that positive findings were shown in these studies is promising when considering physical exercise interventions for adults with ADHD.
More recently, a study showed that exercise seemed especially helpful in improving response inhibition for people with ADHD (Mehren et al., 2019). In this study, researchers asked some people with ADHD and some people without it to do a response inhibition task in an MRI scanner following 30 minutes of cycling and not following exercise. In the ADHD group, patients who had worse response inhibition showed better performance following exercise and also had greater brain activity following exercise. In other words, for people with ADHD, exercise might help by being able to take a moment in deciding how to respond.
How does exercise work its benefits for ADHD?
There are a number of potential mechanisms that might explain why exercise would be helpful for ADHD. Most notably, it supports neurochemicals that facilitate cognition and directed behavior, such as monoaminergic catecholamines, which increase in the brain after exercise in a similar way to some ADHD medications (Wigal et al. 2003).
Dopamine, a neurotransmitter that helps to regulate emotions and motivate action with feelings of pleasure and reward, is considered to be a major factor in ADHD, with most people with ADHD having lower levels than people without it. Along with monoaminergic catecholamines, regular exercise has also been shown to increase dopamine levels in a similar way to some ADHD medications.
While these chemicals respond to exercise and might account for changes immediately afterward, regular exercise might take effect through structural brain changes, cardio-respiratory functioning, improved blood flow, or cell maintenance.
Exercise for Comorbidity in ADHD
ADHD has high comorbidity with other psychological disorders. In fact, studies have estimated as many as 53% of individuals with ADHD also experience depression, and estimates are almost as high for anxiety disorders (Katzman et al., 2017).
Although trials on exercise for ADHD are limited, especially for adults, there are many more indicating that exercise alleviates symptoms of depression – so people with comorbid ADHD and depression are very likely to experience relief from depression at a minimum. There is some evidence indicating exercise reduces symptoms of anxiety as well.
Rates of bipolar disorder are also higher in ADHD (~10-20%; Katzman et al., 2017), and individuals with bipolar disorder should be aware that intense exercise could be dysregulating and contribute to manic episodes. Keeping limits on the amount of exercise, as well as maintaining regular sleep and eating routines, can help to regulate mood for people with both bipolar disorder and ADHD.
Nature might help too
In addition to exercise itself, getting into nature might have its own benefit for people with ADHD. In one study of children with ADHD (7-12 years old), they had better performance on a cognitive task after a 20-minute walk in the park than after a 20-minute walk downtown (Faber et al., 2009). Another study of kids with ADHD (aged 9-17) reported that researchers assessed them to be more social and less aggressive, inattentive, impulsive or hyperactive when assessed at a farm in the woods than in a town (van den Berg et al., 2011).
6 Tips for Exercising for ADHD
So, if you have diagnosed or suspected ADHD, what can you do to get the benefits?
1. Aim for at least 30 minutes/session, 3 times per week. Exercise in any amount is great no matter how small, but most guidelines recommend at least 90 minutes per week. Studies that test exercise for ADHD and mental health use around 30-minute sessions as a minimum, too. If it sounds like a lot, try starting small and building tolerance.
2. Work out right before you need the effect. While there are some studies showing that exercise might be helpful for ADHD in the long run, there is way more certainty that it helps within the hour or two afterward. If you have trouble focusing on work or school at a certain time of day, try to get active right before!
3. Cardio is the best bet. Most research on exercise in ADHD has used cardio exercise, which is exercise involving repetitive movements of large muscles that increases heart rate - like cycling, hiking, dancing, swimming, jogging, or brisk walking. So, to benefit from the cascade of neurochemical changes that can benefit people with ADHD, the best bet is doing the same.
4. Consider exercising in nature. As mentioned above, being outside in a natural setting might have its own benefits for ADHD (and mental health generally). In addition, some research has linked ADHD to higher rates of vitamin D deficiency, so a little more sunshine (which your body can convert in vitamin D) might be helpful too.
5. Work with your ADHD, not against it. People with ADHD tend to find that the usual tips and tricks to plan and follow through with an activity – setting a time aside, putting it in a schedule, creating a goal for the month, etc. – don’t work as well for them. Consider alternative ways to help make it happen using the ADHD motivation system – in which novelty, interest, and urgency reign. For example:
· Choose an exercise activity that is novel and stimulating, like a class you’ve always wanted to try
· Work in something you find interesting, like finding a good podcast for a run
· Buy some new exercise clothes so you’ll be excited to put them on
· Ask a friend to do it with you or hold you accountable to create urgency
People with ADHD also might find those "executive functions" get in the way, so if you:
· Always seem to forget to pack a change of clothes? Keep a change of clothes in the car.
· Can't seem to get out the door? Choose a work out spot that's close to somewhere you already visit regularly, like a gym next to the grocery store or a park next to work. When you are nearby, the mood just might strike!
6. Do something you enjoy. There’s evidence that if you do exercise such as high-intensity training and don’t enjoy it, you might be in a worse mood afterward, and disliking the experience could reduce the chances that you’ll do it again. Picking something you like can help you keep up with regular exercise – and why not have fun with it?
References
Carl, E., Mason, J., Smits, J.A.J., & Asmundson, G.J.G. (2021). Exercise for mental health: Current perspectives, clinical practice, implications, and future directions. In Neuroscience and Biobehavioral Psychology, Comprehensive Clinical Psychology, 2nd Edition. Elsevier. https://doi.org/10.1016/B978-0-12-818697-8.00074-1
Den Heijer, A.E., Groen, Y., Tucha, L, Fuermaier, A.B.M, Koerts, J., Lange, K. and Tucha, O. (2017) Sweat it out? The effects of physical exercise on cognition and behavior in children and adults with ADHD: a systematic literature review. Journal of Neural Transmission, 124, (S-1), pp 3–26]
Faber Taylor A, Kuo FE. Children With Attention Deficits Concentrate Better After Walk in the Park. Journal of Attention Disorders. 2009;12(5):402-409.
Gioia GA, Isquith PK, Guy SC (2001) Assessment of executive functions in children with neurological impairment. In: Simeonsson RJ, Rosenthal SL (eds.) Psychological and developmental assessment: children with disabilities and chronic conditions. New York, NY, US: Guilford Press, pp 317–356
Katzman MA, Bilkey TS, Chokka PR, Fallu A, Klassen LJ. Adult ADHD and comorbid disorders: clinical implications of a dimensional approach. BMC Psychiatry. 2017 Aug 22;17(1):302. doi: 10.1186/s12888-017-1463-3. PMID: 28830387; PMCID: PMC5567978.
Kessler RC, Adler L, Barkley R, Biederman J, Conners CK, Demler O, et al. The prevalence and correlates of adult ADHD in the United States: results from the National Comorbidity Survey Replication. Am J Psychiatry. 2006;163(4):716–23.
National Institute of Mental Health. Attention-Deficit/Hyperactivity Disorder. U.S. Department of Health and Human Services, National Institutes of Health. Retrieved July 26, 2023, from https://www.nimh.nih.gov/health/topics/attention-deficit-hyperactivity-disorder-adhd
Mehren, A., Özyurt, J., Thiel, C.M. et al. Effects of Acute Aerobic Exercise on Response Inhibition in Adult Patients with ADHD. Sci Rep 9, 19884 (2019). https://doi.org/10.1038/s41598-019-56332-y
van den Berg, A. E., & Van den Berg, C. G. (2011). A comparison of children with ADHD in a natural and built setting. Child: care, health and development, 37(3), 430-439.
Wigal, S. B., Nemet, D., Swanson, J. M., Regino, R., Trampush, J., Ziegler, M. G., & Cooper, D. M. (2003). Catecholamine response to exercise in children with attention deficit hyperactivity disorder. Pediatric research, 53(5), 756-751.