It may sound silly, but some experts say laughing can be good for your health—mental and physical. Laughing is like a mild workout: it causes physiological changes, raising our pulse and blood pressure and breathing rate and sending more oxygen to our tissues. One study showed that 10 to 15 minutes of laughter burned 50 calories. There’s some evidence that laughter can even help lower blood sugar levels and help you sleep better. And we all know that laughing usually means we’re among friends—that’s a plus in and of itself, because staying social is one of the best ways to boost mental health (especially in retirement).