Sticking to a nine-to-five workday seems ridiculous, but long hours and work emails are starting to jeopardize our health
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Working overtime can score points with your boss, earn you a raise (or even that corner office!). But it could also earn you a heart attack and depression, according to two new studies that further prove we're spending way too much time on work and not nearly enough on the balance. (Find out how to Sidestep Stress, Beat Burnout, and Have It All-Really!)

Americans are the hardest working people on the planet-or at least we spend the most hours doing it. We work about 1,788 hours per year, more even than the famously diligent Japanese, who work about 1,735 hours a year, and far more than Europeans, who average only 1,400 hours per year, according to the Organisation for Economic Co-operation and Development. Likewise, a Gallup poll last year found that the average American works 47 hours per week. Just eight percent said they work less than 40 hours a week, and nearly one in five of us clocks more than 60 hours a week (that's 8 a.m. to 8 p.m!).

But all those hours aren't necessarily being spent chained to a desk; instead we're chained to a phone. Thanks to the miracle of technology, we're all connected to the office regardless of wether we're actually in the office. And while that can be awesome (answer an urgent work e-mail from the comfort of my own bed? Don't mind if I do!), it also means that work is taking over all hours of the day (another urgent work e-mail when I'm going to bed? I do mind!). (Learn more about how Your Cell Phone Is Ruining Your Downtime.)

There is no such thing as "clocking out" anymore and, while most of us just throw up our arms and say, "It is what it is," our workaholic nature is actually making us sick, according to the new research.

A study published in The Lancet found that the biggest overachievers-those working 55 hours a week or more-were 33 percent more likely to suffer from a stroke and 13 percent more likely to develop coronary heart disease. But the stress harmed even those who only worked 41 hours a week, upping their risk by 10 percent. It's not just the stress, either. The researchers speculate that the increased tension might lead to other risky behaviors like drinking too much, and could compromise healthy habits like spending time at the gym. (Find out How Your Gym Workout Prevents Work Burnout.)

It's not just your heart that suffers during late night project meetings, though. Overtime takes a toll on your brain as well, according to another new study, this one in the Journal of Occupational Health Psychology. German researchers found that employees who were told to be available for work during their off hours were more stressed out and had the higher cortisol levels to prove it-even if no actual extra work was required. It appears that just knowing you might get called on is enough to drive your body into stress city, which in the long-term can lead to mental health problems like anxiety and depression, said the scientists. (See: 10 Weird Ways Your Body Reacts to Stress.)

And trying to set boundaries with your job may be harder on women. For starters, less women have the confidence they'll make it to the top of their field than their male peers, according to a McKinsey and Co. survey, which means those with their eyes on the prize often feel they have to work harder. Then, Women Are Looked Down Upon More Than Men When It Comes to Work-Life Balance.

The worst part though is that all those extra hours don't necessarily translate to getting more work done. According to a 2014 Stanford study, the more hours you work past 40 a week, the less productive you actually are. Officials in Gothenburg, Sweden have taken this to heart and have instituted a six-hour workday after previous experiments showed that shorter-working Swedes were both healthier and more productive, saving the country money in the long run.

But you don't have to move to Sweden to protect your work-life balance. Start with these 15 Simple Steps That Will Change Your Career (and your life!). Because the research is clear: To protect your heart, mind, and sanity, it's time to say no to being on-call 24/7.