At the extremes of latitude the days and nights obey a different cycle than most of us are used to. During spring the sunless days of winter steadily lengthen until the world remains alight 24 hours a day. Inuvik is situated well above the arctic circle, and as the solstice nears, the days here are long. There is a time of dusk around 3AM, but even then it the sky remains fairly bright.
Since I have been here I've found my usual day night cycle thrown off a little. The light is energizing, and plays havoc with any internal chronometer I might have. I find myself wondering why Conan O'Brien is on TV so early, only to remind myself that it is not really early at all but only a trick of the light.
On call last week I was paged back to the hospital just before midnight. The sky was still bright and there were still people out and about enjoying the day. I spent a couple of hours at the hospital admitting a patient, and when I wandered home at 2 AM it was like an early evening dusk. Luckily for me I can sleep anywhere and anytime, so the light doesn't disrupt my sleep at all. The funny thing is that with so much light, I just don't feel like sleeping as much as usual...
Here's what Robert Peary had to say about the arctic sun as he tried for the pole.
It must be remembered that during all this time we were in the region of constant daylight, in the season of the midnight sun. Sometimes the weather was foggy, sometimes cloudy, sometimes sunny; but there was no darkness. The periods of day and night were measured only by our watches—not, during the passage of these channels, by sleeping and waking, for we slept only in those brief intervals when there was nothing else to do. Unresting vigilance was the price we paid for our passage.
From: The North Pole, by Robert E. Peary
Peary's ship, The Roosevelt, at Cape Sheridan