Chances are you’ve noticed that when you’re sick and battling with a hacking cough, it’s often worse at night. And there’s a very good reason for that.

“When you’re asleep, you’re not coughing and cough is the way we get rid of mucus that’s in the airways,” Dr Nick Vozoris, a respirologist and sleep physician at St Michael’s Hospital told Global News.

“So if you’re asleep and you’re not coughing and clearing that mucus that’s building up, you’ll wake up at some point in the night or first thing in the morning and have a lot of mucus you’ll need to get rid of.”

In fact, he says being physically active and moving around can help loosen any mucus trapped in your airways. When you’re not as active – or sleeping – the mucus builds up.