WASHINGTON, D.C. — In the beginning, humans regulated their day by the rising and the setting of the sun. Then someone invented the concept of time and its division into hours and minutes.

With the development of mass media, you could count on your favorite show being on at a certain time of a certain day on a certain station or network just as you could count on the rising and the setting of the sun. Today — except for the sun’s role — much of that has been thrown into question.

Can’t commit to being in front of a radio to hear a certain program? Voila, the podcast that you can access at your convenience. Can’t guarantee you’ll be in front of the set for your favorite show? If you’re patient, you can wait for the full season to show up on DVD. Others seeking more instant gratification can access a streaming service. Or, you can store them in a DVR and watch them on your schedule, not the network’s.

Seventy percent of Americans admit to being binge-watchers. Given how much time Americans spend with the TV on, it was bound to happen.

A friend of mine has on DVD the complete series of the 1960s TV spy spoof “Get Smart.” I envy him slightly, but I don’t know when I’d find the time to watch 138 episodes. I have, though, sat through “High School Musical” and its two sequels — more than once. But that’s a time commitment of a bit less than six hours.

At a recent Friends of the Library book sale, I picked up DVD sets of four of the five seasons that “Lou Grant” aired. Just one season comes to about 18 hours with the commercials gone. I plowed through the first season over one weekend, then thought I’d better save the rest for retirement, when I’ll have more time on my hands.

At some point, my daughter got into a Colombian telenovela on Netflix called “La Reina del Flow” (“The Queen of Flow”). Netflix posted all 82 episodes at once, each running 44 minutes and change without commercials — although Netflix is kind enough to crop out, if you wish, all but the last few seconds of the opening credits and the first few seconds of the closing credits to shave the per-episode commitment to under 43 minutes.

Over Christmas, it seemed as if “La Reina del Flow” was the perfect time-waster when not traveling, going out to eat or visiting friends and family. Two or three episodes after breakfast, and a few after dinner, kept her satisfied — or from being bored, as the case may be.

Set in the intersection of the music and narcotics industries in Medillin, the soap opera of love and revenge had its moral points, although from the English subtitles it was obvious Colombian censors don’t fret as much about bad language as do their U.S. counterparts.

There are teachable moments — such as how some characters value the power of prayer. A teachable moment in the parent-child relationship can manifest itself in other ways, like, “You’ve got time for three episodes before you go to bed.”

Sleep, incidentally, is one of the big casualties of binge-watching. According to Psychology Today, a joint University of Michigan-University of Leuven study found that regular TV viewing doesn’t disrupt sleep patterns, but binge-watching does. Binge watching was linked to insomnia symptoms, fatigue and poor sleep quality. And among those who already had poor sleep quality, a third of them could link it to binge-viewing.

“When we’re deprived of sleep, lots of stuff can go wrong. For one, anxiety and depression can increase. That makes us prone to mistakes, which can stress us out more,” according to an article in USC News, a University of Southern California online publication. “Research shows binge-watchers report higher levels of loneliness and depression.” On the good side, though, binge-watchers said it gave them something to talk about with friends and colleagues.

A 2016 study by three Dutch researchers among Dutch binge-watchers indicated “binge-watching is a solitary activity that occurs in an online socially active context,” they said in their abstract describing the research. “The amount of time spent binge-watching — number of episodes — correlates with the amount of free time and plays an important role in the effect of binge-watching on emotional well-being.”

Their proposed next step, though — “to be able to design and promote a recommendation tool for TV streaming services to create a more optimal binge-watching experience” — makes me think they’d better sleep on it.