Actually, I don't already understand what you mean by real interest and what you mean by nominal interest.
http://www.investopedia.com/articles/investing/082113/understanding-interest-rates-nominal-real-and-effective.aspNominal interest rate Inflation = Real interest rate
A hypothesis maintains that the inflation rate moves in tandem with nominal interest rates over time, which means that real interest rates become stable over longer time periods. Investors with longer time horizons may, therefore, be able to more accurately assess their investment returns on an inflation-adjusted basis.