Physical activity is a good way to boost one's physical and mental health — but not if it's your job, a study claims.

Exercise has long been the primary solution for acquiring a healthier lifestyle. Not getting enough of it is linked to a number of health problems, including obesity, heart disease, diabetes, and many other illnesses.

A new research published in the British Journal of Sports Medicine argues that not all forms of physical activity yield health benefits. In fact, some strenuous work is associated with a risk of early death.

Too Much Physical Activity Might Kill You

Occupational health researcher Pieter Coenen along with his colleagues looked at 17 previous studies that discussed the effects of job-related physical activity. Collectively, the studies provide information on over 193,000 men with varying levels of physically exhausting jobs. They conclude that those with the hardest jobs had an 18 percent risk of dying early compared with people who have less physically demanding work.

The results are conflicting with popular belief. After all, countless studies have been telling us that all forms of exercise can only be good for one's health, right? But Coenen says studies claiming as such only focus on leisure-based physical activity.

"We think physical activity at work and during leisure time are two really different types of exercise with different physiological outcomes as a result," he says.

Two Different Kinds Of Exercises

One big difference between those two forms of exercise is that people who work out for leisure can stay active for a set amount of time and take a break when they become too tired. Meanwhile, people whose jobs require them to remain physically active for hours on end don't get long periods of relaxation. Moderate physical activity may be beneficial for the heart, but intense physical activity may damage it.

"[People with physically demanding jobs] may get very limited rest breaks; their heart rate and blood pressure are consistently high over the entire day. That may lead to the opposite of what is healthy for the heart, namely putting a strain on the cardiovascular system."

What's more, these people may not be getting the right kind of exercise that could be beneficial for their health. Since their physically demanding jobs are hard enough, they might assume working out for leisure is unnecessary.

It should be noted, however, that the study doesn't explicitly conclude physically demanding jobs will kill you. There could be a number of factors why individuals with strenuous jobs are 18 percent more likely to suffer early death — smoking, educational attainment, and socioeconomic standing may all play a role.

Even still, the study highlights that not all exercises are good for one's health.