Fitness space is part of operational capacity

A Type 23 provides routes where sailors can run around parts of the ship, but the enclosed form of a lower-observable Type 45 offers fewer such options. A flight deck can support exercise only when it is not needed for helicopters or other operations. That makes an internal gym more than an optional amenity. Fitness helps keep the crew healthy and alert, while exercise also helps manage stress and mental health during long deployments. As fewer hulls cover more duties, those deployments can grow longer, so removing crew space to fit new equipment carries an operational cost.