SLEEPING solidly for around 150 days is the key to feeling on top, according to ursine sleep experts.

Grizzly bear Roy Hobbs spent three years studying sleep patterns, concluding that less than five months of uninterrupted rest can cause tiredness and mood swings.

He said: “For peak performance, eat shitloads of meat so that you gain about 40 pounds of body fat per week, then go to sleep in early November.

“If you wake up before mid-March, you’re likely to feel groggy and irritable and be more vulnerable to hunters.”

Hobbs recommended a cave or hollow as the perfect sleeping environment.

He said: “You want somewhere isolated so that clumsy teenagers aren’t going to stumble on you, obliging you to tear them to shreds .”

Office worker Emma Bradford said: “I’ve only ever managed nine hours at a stretch, no wonder this morning’s presentation went badly.

“What do bears say about how much water you should drink?”