Not everyone has gotten the message: We can’t afford to sit on our butts all day.

Our bodies need exercise, and two new studies show just how big a boost you’ll get from that sweat.

One of these studies, published in the American Journal of Medicine, finds that just 30 minutes of light exercise like jogging or bicycling three times a week can significantly reduce the risk of early death in people with heart problems.

I know people who spend more time in the bathroom than that – so surely most of us can find that half hour a day.

Researchers tracked 522 people with heart conditions, including high stress, over six years. They were given 12 weeks of exercises classes, then sent on their way.

Those who stuck with it were 60 percent less likely to die over the six-year follow-up period.

The routine they were given was consistent, but not taxing: 10 minutes of warm-ups followed by 30 to 40 minutes of light aerobics – like walking, rowing or jogging. Then, they capped the workout off with 10 minutes of stretching.

Exercise also helped reduce stress levels, a significant factor for heart problems. Prior to the program, one in 10 patients had high stress levels. Afterward, just one in 20 were still fighting that battle.

Another study finds that exercise can make stiff arteries more elastic. In plain English, that means it can significantly lower your risk of heart attack and stroke.

Canadian researchers found that diabetics who got an hour of vigorous aerobic exercise three times a week saw a 15 percent to 20 percent reduction in arterial stiffness. What’s more, they got this boost in just three months.

These subjects were working out relatively hard – reaching 70 percent of their maximum heart rate.

But they started out small with some light exercise and worked their way up – and so can you, even if you never reach that 70 percent level. Any exercise is better than nothing at all.

I know a few seniors who start out using soup cans (unopened, of course) as light weights. And let’s face it – that’s a much better use for these things than eating what’s inside.

Open the can, and you have an unhealthy meal packed in salt and preservatives. Keep it sealed, and you have a dumbbell that only costs a buck or two and is the perfect size for many people in the 65+ crowd.

Just don’t throw the can opener away… you might still need the food in that can in the event of a hurricane or other natural disaster. But that’s about the only time you should consider eating it.

And of course, talk to your doctor before adding new exercises to your daily routine.