Daily Video

November 16, 2012

Why Humans Have to Snooze

On a stressful day it might be the first part of your routine to suffer, but sleep is absolutely essential for humans to remain healthy and productive. However, the question of why we need sleep in the first place has long puzzled scientists.

“The basic driving evolutionary pressure for sleep is still hotly debated, and I don’t even know if we have discovered it yet,” said Professor Robert Stickgold of Harvard University Medical School.

What scientists do know is that when you do not get enough sleep, your mental and physical health starts to spiral downward. Stickgold says that sleep maximizes our capacity for problem solving and information processing. In one experiment, he asked test subjects to solve a maze, pause, and then try again, with and without sleep in between. Those who slept were able to solve the maze on average of a minute faster, and those who dreamed about the maze performed even better than that.

However, sleep also affects how our body works physically. Stickgold says that if you only get four hours of sleep a night, the amount of antibodies you produce against bacteria, against viruses, is dramatically reduced.

“Your ability to process food is altered, so that you have a greater hunger the next day. You start to look pre-diabetic. You will start to put on weight.”

Scientists also suggest that our sleep needs may evolve over time. “It’s possible that, in a few million years, if there are still humans around, we will sleep less, or it may be that we will decide that we enjoy sleeping…we may decide that the thing to do is sleep more,” said Professor Jerry Siegel, a top sleep researcher from UCLA.


“On some level, you can summarize what we know about sleep functions now by saying that if you don’t get enough sleep, you’re going to end up fat, sick and stupid. And that just feels like something my mother used to say to me,” – Robert Stickgold, Harvard Medical School.

Warm Up Questions

1. How many hours of sleep do you get on a typical night? Do you think this is enough? How are weekends different?

2. How do you feel when you don’t get enough sleep?

3. Is sleep is a major priority in your life?

Discussion Questions

1. If you could function with less sleep, would you want to? Why or why not?

2. In your experience, do you think you perform better academically when you have more sleep?

3. What can you do to get more sleep?

Additional Resources

Video Transcript

Test Tomorrow? Get Your Sleep

Teens Explore Dangers of Too Little Sleep

Lesson Plan: Mental Health and Disasters: How Your Body Reacts During and After a Tragedy

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