There is growing evidence that physical activity reduces the symptoms of attention deficit hyperactivity disorder (ADHD). It helps children focus their attention on the task at hand and not get distracted by what is happening around them, two skills that are often deficient in children with this disorder. But what type of physical activity is really beneficial? And at what intensity and for how long is it most effective? A consensus is emerging around these parameters and now makes it possible to formulate recommendations.
Various studies have in fact shown that following a moderate-intensity exercise session, children with ADHD performed better on reading and mathematics tests, had a better level of attention and had better control. their impulsiveness than if they had spent that moment reading or watching a video. “Studies even show that children with ADHD benefit more from physical activity than neurotypical children (without ADHD),” emphasizes neuropsychologist Chaïma Meneceur, who is carrying out research to determine precisely how long after a physical activity session the beneficial effects begin to appear and how long they last.
“Immediately after physical activity, we will not necessarily observe effects on the child’s cognitive abilities. There is a small latency period during which neurobiological adjustments take place,” says M.me Meneceur, who is doing a doctorate at UQAM under the supervision of Claudia Verret, professor in the Department of Physical Activity Sciences, and Marie-Claude Guay, professor in the Department of Psychology and associate researcher at the Center jeunesse de Montréal-Institut university.
For the moment, it appears from the scientific literature that the effects begin to be seen 15 minutes after physical activity and remain present for approximately one hour. Butme Meneceur hopes to clarify the moment when the effect is optimal on motor hyperactivity (agitation), but also on the cognitive level on the different forms of attention, i.e. sustained attention (ability to provide mental effort for several minutes), divided attention (ability to process several different sources of information, such as listening and taking good quality notes) and selective attention (ability to focus on relevant things and ignore the rest) which are affected in people with ADHD.
A “fairly clear consensus” nevertheless emerges from studies carried out to date on the impact of physical activity in children and adolescents with ADHD. The practice of regular physical activity (say three times a week) generates beneficial effects – which are maintained over time – on executive functions, such as action planning, on the ability to remain focused on a task for longer (sustained attention), as well as on inhibitory control (which reduces impulsivity).
Action planning is very affected in children with ADHD, recalls Mme Menace. “They have difficulty organizing themselves, breaking down a large amount of work into subsections. They go all over the place and miss a lot of information. [Ils ont un déficit quant à] the ability to plan action and anticipate, two skills that allow us to achieve the goal optimally, without spreading ourselves too thin,” she explains.
Physical activity parameters
The parameters of physical activity prove to be decisive in the effects that we will observe, warns the neuropsychologist. Firstly, intensity is of great importance. If it is “light, the effects will not necessarily be observable all the time,” says M.me Menace. Moderate-intensity activity is optimal for affecting functioning [cognitif] and on hyperactivity. On the other hand, when the activity reaches a very high intensity, it can cause a “fatigue effect”, and at that moment, “the body will instead try to put its energy into regaining a certain stability, which we call homeostasis, and will not necessarily have the effect we hope for on hyperactivity and on the level of cognition.”
Moderate-intensity activity can be different from person to person, as it corresponds to an intensity of approximately 65% of the individual’s maximum heart rate. A smart watch that measures heart rate can help determine the intensity at which this value is achieved.
The same phenomenon is observed with duration. We do not necessarily see spectacular effects when physical activity is less than 15 minutes. A duration of between 30 and 45 minutes at moderate intensity seems optimal. Beyond 45 minutes to an hour, the body may have an overload of fatigue which makes it difficult to return to balance. Studies of marathon runners have shown that at the end of their event, many of these athletes had lower cognitive abilities than they normally had before the race, notes Mme Menace.
Aerobic activities, the most studied, are those for which the most notable effects have been observed. When aerobic activities, such as running, swimming and cycling, were compared to somewhat calmer activities, such as yoga, it appeared that the aerobic type had a greater impact. Perceptual-motor exercises that particularly require coordination, such as rhythmic dancing, also prove to be very effective, underlines the scientist.
Researchers have observed that aerobics increase blood flow to the brain, which will thus be better oxygenated and better supplied with nutrients. It increases the concentration of certain neurotransmitters, including dopamine, which is insufficient in people with ADHD. It would also induce the secretion of neurotrophic factor from the brain (BDNF for “ brain-derived neurotrophic factor ), which promotes neuroplasticity. Clearly, these neurobiological phenomena help to alleviate the various symptoms of ADHD.
Research also indicates that an exercise program respecting these different parameters should be adopted from an early age by children with ADHD or who are suspected of being at high risk of developing this disorder. Such a program would be particularly important during child development and adolescence.
“We can only recommend physical activity because children with ADHD are often more at risk of engaging in more sedentary activities. Which may seem paradoxical given that they are hyperactive, but they have a particular attraction to such activities, like video games and television. They may even become addicted to video games. Young people with ADHD have a much greater risk of falling into addiction, and this can be to video games, but also to drugs,” emphasizes M.me Menace.
Can physical activity replace medication? It all depends on the severity of the disorder, says Chaïma Meneceur, who works in a clinic with young people with ADHD. “When the disorder is mild, some manage to compensate with physical activity and cognitive-behavioral therapies, which help reduce the anxiety which exacerbates attentional difficulties. » For more severe cases, the most reliable studies present physical activity as a complementary treatment, rather than a replacement. “Medication really remains the main treatment. But by adding physical activity, and why not cognitive-behavioral therapy, we further improve the chances of seeing symptoms decrease. »