If you start your day at work already exhausted, you're not alone.

According to The General Social Survey of 2016, nearly 50 percent of people say they are "often or always exhausted due to work," which is a 32 percent increase from 20 years ago, reports Harvard Business Review.

Sixty-three percent of people say they have "high levels of stress at work, with extreme fatigue," according to a 2012 CompPsych survey, writes USA Today. Thirty-six percent "just work harder" to cope.

"People are so exhausted because they are always on," Steve Magness, co-author of "Peak Performance," tells CNBC Make It.

The problem is, no one gets better at their job just by pushing harder and harder, as New York magazine points out in an interview with Magness and his co-author, Brad Stulberg.

Magness, who coaches professional runners, began researching "Peak Performance" to find out how driven individuals can get ahead in their fields, without burning out. What he found is that while stress is necessary for growth and performance, so is recovery. People need to "let their minds bounce back and rest so that they feel rejuvenated," he says.

Here are five simple strategies you can use every day to be more productive without losing your stamina.