Question: what is good for your heart?
Answer: anything that makes it beat faster. "Exercise that is good for the heart has got to be aerobic," says Penny Hunking, a nutritionist and exercise expert.
"Aerobic" means using or requiring oxygen, and "aerobic activity" is defined as "any repetitive, rhythmic exercise involving large muscle groups."
"So we're talking about brisk walking, power walking (striding out, with arms pumping), jogging, rowing, cycling, swimming or even dancing," says Penny, who runs a consultancy called Energise.
What if the weather's bad? "An exercise bike can be convenient," she says without great enthusiasm. "You can sit and pedal and it'll give you all sorts of technical information. You can do it while watching TV or a movie."
However, as with much home exercise equipment, exercise bikes tend to sit unused after an initial spurt of zeal. Better, she says, to get out into the fresh air on a real bike, or combine exercise with social life by playing a team game with friends.
But you don't have to stick to conventional ways of keeping fit. "Dancing is good," she says. What kind? "Anything you want, from ballroom to break-dancing to disco."
So is skating, on ice, roller skates or blades. And aqua-aerobics is good for both heart fitness and body tuning, as arms and legs encounter great resistance as they push through the water.
Then there is the wonderfully named "fartlek" (Swedish for speed play) - alternate walking and running - which is good for training.
"It's very effective because you huff and puff while you're getting your heart rate up and then have rest periods," says Penny. "You can match the intervals to your level of fitness."
How do you know when you've pushed yourself hard enough?
Exercise experts have a simple test, she says. If you can still sing, you're not working hard enough - and if you can't talk, you're probably overdoing it.
It is worth the effort. Not only does exercise make you feel happier, it halves the risk of developing coronary heart disease.
And if, despite regular exercise, you do have a heart attack, you are twice as likely to survive it www.bhf.org.ukwww.energise.org.uk