Sleep differs by age, geography and gender, scientists say

Sleep isn't the same around the globe, or even between genders.

Scientists say people in Europe and North America sleep the longest, while those in Asia sleep the least.

People go to sleep later in the Middle East, but much earlier in the Pacific Islands and Australia.

Young women sleep more than young men, and they fall asleep earlier.

This new study also found that the circadian rhythm shift which causes teens to sleep later actually continues into the mid-20s.