MIAMI (CBS) — Are you getting the kind of sleep you should be?

Dr. Daniel Buysse, with the University of Pittsburgh’s Sleep Institute, said what you think about getting a good night’s sleep may not be true.

We Should All Get Eight Hours Sleep

“Not true,” said Dr. Buysse. “People vary in terms of how much sleep they need.”

The normal range for most adults is six-and-a-half to eight hours.

You Can Catch Up on Sleep

“Only partially,” said Dr. Buysse. “You can catch up on sleep for some sleep that you lost, but you’ll never make up for an entire night of lost sleep.”

If You’re Sleeping Very Little, You’re More Likely to be Overweight

That turns out to be true.

“There’s actually quite a bit of evidence linking very short sleep to obesity and to the tendency to gain weight overtime,” said Dr. Buysse.

By “very short” he means fewer than six hours on a regular basis.

It Doesn’t Matter What Time of Day You Sleep

“That is absolutely false,” said Dr. Buysse.

Human beings have biological clocks that want us to sleep at night, according to Dr. Buysse who added that we just don’t sleep as well during the day.

Sleeping in a Cool Room Is Best

That depends on your definition of cool.

“The range of ideal sleep is between 65 and 75 degrees,” said Buysse.

He adds if a room is too hot – or too cold – you’ll wake up more.

A Glass of Wine Can Help You Sleep

“Alcohol does help people to sleep,” said Dr. Buysse.

But it turns out that it’s only partially true.

“The problem with alcohol if you use it as a sleeping pill at bedtime,” said Dr. Buysse, “Is that it doesn’t last that long and people tend to wake up and have insomnia in the middle of the night.”

If You’re Having Trouble Falling Asleep, You Should Get Out of Bed

He said this is true.

“It’s better to get out of bed, go somewhere else and only when you start to feel sleepy, go back to bed,” said Dr. Buysse.

Getting Older Means Worse Sleep

The answer here is complicated.

“Sleep tends to be lighter and tends to get more fragmented,” said Dr. Buysse.

People wake up more during the night. However, he also said that as we get older, we seem to need a little less sleep anyway.

Naps Are A Waste of Time

“Naps are not a waste of time,” said Dr. Buysse. “Naps are sign that your brain needs more sleep.”

He said a half-hour nap can work well for a lot of people and that some people find a 10-minute power nap useful.