Jeff Bezos, the founder of Amazon, is apparently running his business like a 21st-century tech sweatshop. As reporters from the New York Times Jodi Kantor and David Streitfeld put it, "[Amazon] is conducting a little-known experiment in how far it can push white-collar workers, redrawing the boundaries of what is acceptable."

On the other side of the marketplace, Netflix announced early in August unlimited maternity and paternity leave. This, evidently, on top of the company's already unlimited vacation plan. Reed Hastings, the Netflix co-founder, explained his company's thinking in a piece for Bloomberg Businessweek a few years ago. "We focus on what people get done," Hastings wrote, "not on how many days they worked."

Kind of a no-brainer for Best Places to Work 2015?

Squeezing the most out of workers, without squeezing too hard, has been a balancing act for centuries. Now comes a study that, in a scientifically "Well, duh!" kind of way, suggests something that anybody who ever walked out of the office late and trudged home to a cold dinner already knows.

Too much work is not good for you. Seriously not good for you.

Overtime is no good time

The study, published online in the Lancet Medical Journal on Aug. 19, was not some flip-through of medical charts for a dozen or so guinea pigs. The authors of the paper gathered the data and research from 25 studies done throughout the U.S., Europe and Australia over several years — studies that covered more than 600,000 test subjects — to back up what many of us suspected.

Their bleak conclusion: "Employees who work long hours have a higher risk of stroke than those working standard hours."

The study wasn't as conclusive on coronary heart disease, something it was examining. But its findings on stroke, and the correlation between the amount of overtime a worker puts and an increased risk for stroke, was startlingly obvious.

For example: An employee, man or woman, who put in 55 hours of work in a week or more was 1-3 times more likely to have a stroke than someone who puts in a standard amount (35-40 hours) and goes home. "This association is biologically plausible," the researchers — more than two dozen of them, from the University College London, Sweden, Germany, Finland, Belgium and elsewhere — wrote. "Sudden death from overwork is often caused by stroke and is believed to result from a repetitive triggering of the stress response."

Work is gonna get you

The study suggests a few other ways, other than stress, that long hours may lead to poor health.

First, there is the simple fact that work, for many of us, involves sitting on our butts for too long. Or, as a popular slogan goes, "Stillness is what kills us."

"Behavioral mechanisms," the study says, "such as physical inactivity, might also link long working hours and stroke; a hypothesis supported by evidence of an increased risk of incident stroke in individuals who sit for long periods at work.”

Second, those long hours of sitting on our butts keep us away from other activities that might alleviate that stress or help to deal with it. Specifically, exercising. We work too long, we miss workouts. We miss exercising … all sorts of bad things can happen.

Third, heavy drinking — never good for your health — "might be a contributing factor because employees working long hours seem to be slightly more prone to risky drinking than are those who work standard hours," the study says.

Lastly, working long hours might make you hardheaded. Says the study: "[I]ndividuals who work long hours are more likely to ignore symptoms of disease and have greater prehospital delays in relation to acute cardiovascular events than do those who work standard hours."

None of this is to say that the employees at Amazon need to start doubling-down on their health insurance or making sure that the will is updated. But, certainly, the study reaffirms that we have to watch the clock, at least once in a while, for our own good.

It also makes Hastings look like the boss of the year. "Hard work, like long hours at the office," he wrote, "doesn't matter as much to us. We care about great work."

Now that's an idea worth getting all worked up about.