When is the buoyant force on a swimmer the greatest, when the swimmer is exhaling or inhaling?

The buoyant force on a swimmer is greatest when the swimmer is exhaling. This is because when the swimmer exhales, they are expelling air from their lungs, which decreases their overall volume and density. This decrease in density causes the swimmer to become more buoyant and float higher in the water. On the other hand, when the swimmer is inhaling, they are taking in air, increasing their overall volume and density, which decreases their buoyancy.

Inhaling