That's nonsense. There's no objectively healthy inflationary rate.

Low interest rates are the key factor in driving demand for borrowing. Low interest rates signal a healthy supply of savings from which to borrow. So, low interest rates naturally match a large supply to a healthy demand. Such a scenario would create a market for investment-led expansion.

High interest rates signal the opposite. Either the supply of available savings is insufficient, or relative demand is high enough to drive out uncompetitive demands for savings.