Daylight saving time ends at 2 a.m. on Sunday, which means an extra hour of sleep.

But how does this time change affect your body?

“Negatively. Even if we can’t hear it, we all have an internal clock,” says Anita Layton, professor of biology and mathematics at the University of Waterloo.

Whether it’s a “forward swing” or a “backward swing,” Layton said it disrupts our body’s clock.

“It tells you when you should wake up, why you should eat, when you should go to bed. And then light is a very important regulator of this circadian rhythm. So when you change the amount of light exposure you get, you mess it up,” Layton said.

Neither time change, she said, is ideal because they pose some physical health risks.

“With daylight saving time in the spring, we see an increase in heart attacks,” Layton said. “The week after the time change, you tend to be hungrier in the fall as you are in the spring… You have less leptin, which is the hormone you want to feel full after eating.”

Perhaps unsurprisingly, this also takes a toll on your mental health.

“Not getting enough sunlight is not good for your health. This makes your body less able to produce serotonin,” she says. “Vitamin D is a vitamin deficiency that is also associated with depression and fatigue.”

She explained that people with different mood disorders tend to have more difficulty with the time change because it is associated with seasonal depression.

So with the clock ticking down, Layton suggests people stick to the timing of their usual routines as much as possible when it comes to sleep, workouts, and meals.

But Layton has strong feelings about the biannual change.

“Just get rid of it.” I’ll stick with daylight saving time or standard time. I don’t care. Stick to one already.