Is marriage good for you? It depends which medical expert you ask. Some claim it’s the equivalent of a gym membership, which is both depressing (nothing is bleaker than a gym membership) and encouraging (hey, I can cancel my gym membership). Others claim it makes little difference.

The latest evidence is confusing. One study found that married people have lower stress levels than singles. Another found that people with type 2 diabetes or high cholesterol are more likely to survive if they’re married. And there is evidence that marriage reduces the risk of heart attack. All of which suggests that everyone should tie the knot immediately.

Except now there is another study, of 11,000 Swiss people, which says that married people become less healthy over