The Aussie's own notes specify one to two hours daily and describe a working dog that excels at sports. Its 5/5 for both energy and exercise is honest, and the mental component is not optional.
What satisfies an Australian Shepherd is a task with rules: herding, agility, obedience, rally, disc, scent work, or structured training sessions. Distance alone does not do it. A five-mile run produces a fitter Aussie with the same unmet need, and that need surfaces as behaviour — herding children and other pets, nipping at heels, chasing bicycles and cars, patrolling, shadow and light chasing, and obsessive repetitive habits that are genuinely difficult to unpick once established.
The Pit Bull's 4/5 is a simpler proposition. An hour to ninety minutes of real activity — a brisk walk plus flirt pole, spring pole, tug, weight pull or a training session — and the dog settles. It is strong and athletic and it enjoys work, but it does not have the herding breed's compulsion to be employed. Its 3/5 tolerance for time alone against the Aussie's 2/5 reflects the same difference.
Both rate 2/5 for first-time owners, and both fail when under-exercised, but the failure modes differ. An under-exercised Pit Bull is mouthy, destructive and harder to manage around other dogs. An under-exercised Aussie becomes frantic, obsessive and neurotic.
On space, the Aussie's 1/5 for apartments against the Pit Bull's 2/5 is fair. Neither is ideal in a flat, but the Pit Bull is quiet at 2/5 barking, settles hard indoors and needs less, while an Aussie in a flat needs its whole requirement met outside the building every single day.