Doesn't affect existing debt but as bonds mature they need to be replaced and that's when servicing costs go up. That happens all the time since bonds are alway

Doesn't affect existing debt but as bonds mature they need to be replaced and that's when servicing costs go up. That happens all the time since bonds are always maturing, but there are different maturities (2, 10, 30 year) so servicing costs go up relatively slowly.