Winter is a painful season for Satoko Kojima (not her real name), a Tokyo office worker who says she cannot tolerate cold temperatures.

In the morning when waiting on the platform for her train, her toes go numb. At work, she is not comfortable without a blanket on her lap, even though the office's temperature hovers around 30 degrees. Compounding the problem are neck and jaw aches because Kojima unconsciously stiffens her body and clenches her teeth whenever she is cold.

"I really envy people who have no problem with cold weather," she says with a sigh.