What's the best temperature for sleeping?

While other experts think mostly about optimal indoor temperatures for day-time settings like offices and malls, Ilene Rosen spends her time thinking about the night, a source of conflict in many households.

"The best temperature for great sleep is between 60 and 68," said Rosen, a Penn Medicine sleep specialist who is president-elect of the American Academy of Sleep Medicine.

"The temperature of the world drops at night and [our ancestors] slept in a cave. This is why your bedroom should be like a cave, dark and cool because core body temperature need to drop."

Rosen said she doesn't see gender differences on this. In fact, menopause makes some women run hot at night. It's OK if you need a blanket at those temperatures. Affording that level of cooling is another matter. Fans can help.