Let's say you have two possible projects: X is investment in growth, which will result in increase of your revenue in the short term, and Y is investment in reduction of risks which will increase the value of your assets in the long term. If interest rates are low, borrowing money for Y or for both projects becomes more tangible option. If interest rates are high and you are an optimist, you will choose to borrow money for X. Based on this logic, higher interest rates would expose the optimism of the investors better. Whether there is a causal link between them or not, that is an open question.