If the fast-approaching swimsuit season isn’t motivation enough, here’s one more reason to whittle down your waistline. A recent study in France, which considered more than 120,000 people’s waist sizes in relation to their overall health, has discovered a conclusive correlation between the size of your middle and your lungs’ ability to do their job. The danger zone begins when the circumference of your waist tops 35 inches if you’re a woman, and 40 inches if you’re a man. This research builds upon previous findings, which established a connection between waist size and increased risk for diabetes, high blood pressure, and heart disease. All of the sudden, a few sit-ups doesn’t sound like such a bad idea!