Sleep Patterns?

I heard a passing verbal blip on the radio that made me ever so curious something about first and second sleep, and history. . .what? Time to visit our friend Google. 

So some excerpts from Wikipedia:

Segmented sleep

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Segmented sleep, also known as divided sleep, bimodal sleep pattern, or interrupted sleep, is a polyphasic or biphasic sleep pattern where two or more periods of sleep are punctuated by a period of wakefulness. Along with a nap (siesta) in the day, it has been argued that this is the natural pattern of human sleep.^[1][2] A case has been made that maintaining such a sleep pattern may be important in regulating stress.^[3]
Historian A. Roger Ekirch (2001,2005) argues that before the Industrial Revolution, segmented sleep was the dominant form of human slumber in Western civilization. He draws evidence from documents from the ancient, medieval, and modern world, which he discovered over the course of fifteen years of research. Other historians, such as Craig Koslofsky,^[4] have endorsed Ekirch's discovery and analysis.

 According to Ekirch's argument, typically individuals slept in two distinct phases, bridged by an intervening period of wakefulness of up to an hour or more . . .  . . .

The human circadian rhythm regulates the human sleep-wake cycle of wakefulness during the day and sleep at night. Ekirch suggests that it is due to the modern use of electric lighting that most modern humans do not practice segmented sleep, which is a concern for some scientists.^[8] Superimposed on this basic rhythm is a secondary one of light sleep in the early afternoon and quiet wakefulness in the early morning.
There is evidence from sleep research that this period of nighttime wakefulness, combined with a midday nap, results in greater alertness than a monophasic sleep-wake cycle.
. . . .

The modern assumption that consolidated sleep with no awakenings is the normal and correct way for human adults to sleep may lead many people to approach their doctors with complaints of maintenance insomnia or other sleep disorders. If Ekirch's theory is correct, their concerns might best be addressed by assurance that their sleep conforms to historically natural sleep patterns.^[9]

Is left me wondering is the 8 hr sleep just a modern construct?? Intriguing thought. Why not? Maybe insomnia isn't an epidemic here, maybe it is a mis- perception

Let's see per sleepcottage.com:

Insomnia statistics
- 20 to 40% of all adults encounter insomnia problems during a year time.
- More than 2 million children suffer from various sleep disorders.
- Almost 35% of people suffering from insomnia have a family history of insomnia.
- We now sleep 20% less than we did 100 years ago.

So still wondering now is it really insomnia  . . .

and the bigger question how do we accept as truth without giving it a second thought?