"When you leave people to their own devices and don't constrain them, the results are mind-blowing, " Naumoff said.

CNN: , for

Each sleep position has benefits and disadvantages, although sleeping on the stomach generally isn't recommended because it can constrain the neck.

WSJ: Find the Perfect Sleep Position

On Monday, Mr. Kerry told reporters in London that Iran could face "terrible consequences" if it didn't take advantage of the current diplomacy and agree to constrain its nuclear program.

WSJ: Kerry Hits Bumpy Road in World Diplomacy