Granted, you get a lot of exercise after you drop the hook but when you're on passage there's no exercise unless you're doing it the wrong way. If you get your exercise on shore it's not sailing exercise.
An example,, on the passage from Isla Mujeres in the Western Caribbean to the Dry Tortugas ( almost 400 miles ) there's nothing to do but sit on your butt. That's 4 days of sitting on watch or lying in the bunk trying to get some sleep. For us with only 2 aboard we have 3 hour watches (more if one of us is tired or under the weather). That's not a lot of sleep at one time and, while you're on watch you don't do much except for tweak the sails once in a while because the distances you're traveling don't demand much in the way of changes. That's not a lot of work. Now, if your racing it's different. Racing is a lot of exercise.
I don't buy 'hand steering' as work. Hand steering is only a way to keep yourself active. Personally I don't see any benefit in hand steering. If you want to keep active, make a flute out of a piece of driftwood.
OK everybody, tell me I'm wrong. Tell me that when you do a week at sea you get a lot of exercise. I'd say it's only if there's a storm and you're scared. Then, your scared and really tired but generally not from exercise, from just trying to keep from hurting yourself and not getting any sleep. Oh yeah, you're also hungry because you ran out of pre made foods and are too uncomfortable to make spaghetti.
Exercise and passage making, I don't think it happens. That's why I have the dumbell,,,, or is it me that's the dumbell.