Normally, the main causes of cyclical fluctuations in economic activity are related to changing levels of investment and government spending. This is because a large proportion of consumer expenditure is financed from loans more than current income. As a result, consumption begins to be increasingly influenced by interest rate. Also size reduction policy interventionist government spending led to different effects on the overall level of economic development. Cyclical changes may thus alter the macroeconomic conditions and regional supply, with direct influence on the level of potential output in two ways: - by increasing or reducing prices of primary goods; - the impact of technological innovations on the level of economic activity. In terms of historical changes in the level and quality of energy sources or means of transport are significant examples in this regard.