Keeping a secret doesn't just take a toll on your mental health -- it can also feel physically burdensome, a new study suggests.

Researchers from Tufts University found that people who know of another's deep secret -- for example, one concerning sexual orientation or infidelity -- were more likely to perceive certain tasks as more arduous.

For one part of the study, participants were asked to remember a secret they were told -- some were asked to remember a "meaningful secret," while others were just asked to remember a "small personal secret," Everyday Health reported. Then, they were asked to estimate things, including how steep a hill was and how far a distance was.

The people with the meaningful secrets "estimated hills to be steeper [and] perceived distances to be farther," researchers wrote in the study.

And in another part of the study, researchers had people who'd recently been unfaithful to a partner rate how much that act of infidelity bothered them, Everyday Health reported. Then, they were asked to say how much effort it took to do tasks like give carry groceries upstairs, help someone move, or walk the dog.

The researchers found that the people who were more weighed down by their acts of infidelity were more likely to say that the everyday tasks required more effort and energy, according to the study.

"The more burdensome the secret and the more thought devoted to it, the more perception and action were influenced in a manner similar to carrying physical weight," researchers wrote in the study. "Thus, as with physical burdens, secrets weigh people down."