Neurophyschologist Barbara Fisher describes people with Inattentive ADHD as anxious and unable to relax.
Conversely, other ADD experts claim that many people with Inattentive ADHD tend to be lethargic and hypoactive. These contradictory descriptions may possibly be related to body type.
Males tend to fall into three main body types: mesomorphs, endomorphs and ectomorphs. Mesodomorphs tend to be muscular and moderately energetic, ectomorphs tend to thin and nervy, while Endomorphs tend to be sluggish, easy-going and prone to putting on fat. Women also fall into these three main body types although the differences are not usually as pronounced.
Hence it may be that Inattentive ADD types who are hypoactive tend towards the endomorphic body type, while Inattentive ADD types who are anxious and restless lean towards the ectomorphic type.
I tend to have a lot of physical restlessness with my ADD symptoms and I definitely have an ectomorphic body type. I usually constantly fiddle with things like pens and find it hard to sit still and concentrate if I don’t get some physical exercise during the day. Even though I tend to be short on mental energy a lot of time I usually have plenty of physical energy.