Katie Couric's Notebook: SAD Story

Hi, everyone.

Feeling the winter blues? You're not alone.

Almost one in five Americans lives with some form of seasonal affected disorder -- known, appropriately enough, by its acronym: SAD.

As days become shorter--and darker--SAD sufferers experience declines in mood, energy, and productivity, symptoms that can last from as early as September to as late as April, depending on where you live -- leading to a seven-month long, yearly depression for millions of people.

Promising research suggests that seasonal affected disorder resembles jet lag in the way it interrupts our sleep cycle and may be treated with tiny doses of melatonin.

But until this new theory is proven, medical experts agree that exposure to high-intensity light boxes--which can replicate summer sunrises--are a big help.

As always, we're urged to resist the temptation to carbo-load in the winter and--difficult as it is--to stick to a regular exercise plan.

That's a page from my notebook.