Hyperactivity is a key component of ADHD. Although in the past it was thought that only people who were visibly hyperactive had ADHD, it is now known that the hyperactivity in ADHD brains can be presented both externally and internally. 

External hyperactivity presents as hi energy, can't sit still, speaking out of turn, and impulsivity. In childhood it can look like an unruly child that has no discipline. In adulthood it can present as constantly fidgeting, moving around, unable to sit still, and impulsive risky behavior.

Internally, hyperactivity can present as impulsively blurting out answers to questions, seemingly sporadic conversation topic shifting, and lack of focus on a subject.

Hyperactivity tends to present itself more when triggered. Every person will have different triggers to their ADHD, however, here is a list of common triggers: ‌

Stress

Stress is a common trigger for ADHD episodes . At the same time, ADHD can put a person in a constant state of stress. ADHD causes a person's stress levels to rise because they are unable to focus and filter out excessive stimuli. Anxiety, which can be caused by looming deadlines, procrastination, or an inability to focus on the task at hand, can exacerbate stress. Unmanaged stress exacerbates frequent ADHD symptoms.

Lack of Sleep

Poor sleep causes mental sluggishness, which can exacerbate ADHD symptoms and lead to inattention, tiredness, and sloppy errors. Sleep deprivation also affects performance, focus, response time, and memory and comprehension. In attempts to compensate for their tiredness, a youngster who gets too little sleep may become hyperactive. A child or adult with ADHD who gets at least seven to eight hours of sleep each night may be able to regulate unfavorable symptoms the next day.

Food and Additives

Certain foods can either improve or aggravate ADHD symptoms. It's critical to pay attention to whether certain meals increase or alleviate your symptoms when dealing with the disorder. Proteins, fatty acids, calcium, magnesium, and vitamin B aid to properly fuel your body and brain, and may help to alleviate ADHD symptoms.

Some foods and food additives have been linked to the exacerbation of ADHD symptoms in some people. Foods high in sugar and fat, for example, may be crucial to avoid. Certain additives used to improve the flavor, taste, and appearance of meals, such as sodium benzoate (a preservative), MSG, and red and yellow dyes, may increase ADHD symptoms. According to a 2007 study, artificial colors and sodium benzoate are linked to increased hyperactivity.

Overstimulation

Many people with ADHD endure episodes of overstimulation, in which they are overwhelmed with distracting images and noises. Congested places, such as music halls and amusement parks, can exacerbate ADHD symptoms. Allowing enough personal space is vital for averting outbursts, thus avoiding crowded restaurants, rush hour traffic, crowded supermarkets, and high-traffic malls may help alleviate unpleasant ADHD symptoms.

Technology

Constant technological stimulation from devices such as computers, mobile phones, television, and the Internet, may further exacerbate symptoms. Although there is great controversy regarding whether viewing TV affects ADHD, it may exacerbate symptoms. ADHD is not caused by flashing pictures or loud noises. However, if a child is having difficulty focusing, a dazzling screen would make it much more difficult for them to concentrate.

A child is also far more likely to release pent-up energy and develop social skills by playing outside than by sitting in front of a computer for lengthy periods of time. Make a point of keeping track of your internet and television usage and limiting your viewing to certain times.