Investor's risk in the event of a change in interest rates on bond market

Even if an investor wants to actively manage his portfolio, he should study in detail what the behavior of the bonds is based on their maturity, their yields and in the event of a change in interest rates. An increase in interest rates will lead to a reduction in the prices of all bonds. 
One risk to consider is that the issuance rates of new bonds also change the returns required by investors to buy or sell bonds already issued. Bond prices correspond in the opposite direction to interest rates, in which case an increase in interest rates will result in a fall in the prices of all bonds. Another risk is the decision to choose a bond based on the maturity time, where the longer the time, the more volatility it will have due to the change in interest rates. As well as the percentage change in the price of the bond increases with a decreasing course when the maturity of the bond increases. But even in the case of an equal change the yield at maturity will not be symmetrical in any case. Finally, the investor should calculate the risk in the behavior of interest rates, where the smaller the interest rates of the bond, the greater its volatility in price, as interest rates change.
In summary, the investor should calculate the risks based on the bond maturity maturity parameter and the amount of the issue interest rate, ie the bond interest rates he wishes to add to his portfolio. These two factors are the interest rate risk.