The disturbing thing is that, despite interest rates being very low at this time, a whole 10% of the government revenue is going to paying off interest. 20-year yields on Treasury bonds are only 2.5% right now, but it has usually been 4% or higher. It is only low now because so many investors have fled the stockmarket in uncertain times, and Treasury bonds are have traditionally been considered "safe". When interest rates go back to their normal levels, the share of government revenue that goes to pay of the interest rate will increase.
Even if the interest only went up to 20% of the government revenue, which is very plausible within the next decade, this could be a great burden on both the government budget and the economy as a whole. If 40% of government taxation went to paying off debt, there would no doubt be big problems, severe cuts would have to be made to social programs and defence, and taxes would have to be increased. This could indirectly cause more unemployment.
All this borrowing naturally effects interest rates in the rest of the economy.