If the government borrows a lot of money, what will this do to interest rates?

Interest rates will eventually go up because there is a massive amount of borrowing by the federal government. This is the result of the amount the government is spending - budget deficits. But gov mustn't have never had this level of spending. The government must borrow to cover all this spending. Much of the borrowing is from foreign countries such as China, India, Brazil, Japan, European countries, etc. Over time, the only way that they will loan us money is if we pay them more for the risk they are taking - which means paying them a higher interest rate. This is a major concern for the country in the long term. I hope that makes sense and helps you.

And here is the graph: it shows aggregate demand shifting left because interest rates had mount.







As Chris Told, Change in interest rates will have an impact on Unemployment, inflation, Exchange rates. All this macro economic stuff. And then The effect on inflation causes more problems, savings, etc. And then Wages, cost of production.
Crisis will occur. Entire economy will struggle causing downward growth. All this stuff could happen just because of over borrowing. I will suggest you something, " don't even borrow money from your friends, this will make successful man in the future" )