Forty Germans jumped into an ice-cold Berlin lake for their annual Christmas Day swim for good health, undeterred by floating ice chunks or water temperatures of one degree Celsius (34 degrees Fahrenheit).

The men and women, nearly all of them naked, spent about five minutes in the water during the traditional swim on Thursday last in Berlin?s Oranke Lake which they believe is good for their health and for a laugh.

The tradition goes back many years though no one knows for sure how many. The swimmers ? outnumbered by camera people drawn to the annual media event ? built up their courage for the dip by singing Christmas carols.

?It?s actually sick to get up so early and jump into such cold water,? said shivering Max Korinke. Christl Barth added: ?I?d never do this on my own, but in a group you lose your inhibitions.?