This paper advocates that low income countries' vulnerability to external shocks be taken into account in connection with indebtedness. It names several sources of volatility affecting these economies and puts forward a new way to measure shocks, defined as the deviation of a macroeconomic variable (such as exports) from its 5-year moving average. It also documents the links between shocks on LICs' export earnings over the past 30 years and the probability that they faced a debt crisis, such as default or rescheduling. Finally, it describes the mechanisms of a new lending instrument which would enable the prevention of an accumulation of debt problems by allowing for the suspension of repayments in case of a shock.