They need fun, not a workout
In my opinion bulldogs are the best dogs, because all they want is love. They need to be outside, get some sun and fresh air and move around, but you don't have to put them through an exercise regimen. They don't need a big yard either. They want to hang out, be petted and be funny. That's why they're good for apartments and for houses.
Activity level depends on the bulldog. A well-built dog like DaChamp, with a strong back and strong hips, will be more active than a bulldog that isn't as structurally sound. Ours are agile and active, but still have that chill, funny bulldog attitude.
Warning: be careful when it's hot and humid. Don't overwork your bulldog. Let them rest, put them in the AC, and always give them water.