A British scientist says he has proven January 23 to be the year's lowest emotional point.

Cliff Arnall has made the calculation after coming up with a special formula of personal and seasonal factors.

The variables are weather, debt or monthly salary, time since Christmas, time since failure to quit a bad habit, low motivational levels and the need to take action.

On January 23 people face bad weather and holiday debts, and in the meantime don't have a lot of events or parties to anticipate.

His formula is said to be valid for the UK and most of the United States.

But Arnall, who is a health psychiatrist at the University of Cardiff, Wales, says there are ways to beat the blues.

He advised people to take walks, exercise, do something unusual and stay around people they like.