Play guitar for a few hours
Stay seated throughout your guitar practice and you'll burn around 140 calories per hour – so you'll need to keep playing for more than three hours to reach that '500' target. Stand up, however, and you'll burn off 200 calories in an hour – even more if you move around while you play. Either way, you'll boost your musical skills while you burn those calories. Another benefit? Learning to play a musical instrument may lower dementia risk, according to a University of California study.
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Clean the house for two hours
A two-hour cleaning blitz can help you shed up to 600 calories, according to recent research by the Good Housekeeping Institute.
The most effective task? Forty minutes of dusting burns off nearly 200 calories, while 20 minutes of vacuuming or mopping sees off a further 100. The added benefit? You'll have a squeaky-clean house at the end of it, obviously.
How to turn your cleaning session into a workout
Ride a horse for two hours
Riding a horse at a walk, trot or canter can burn up to 500 calories in a couple of hours. You'll also experience the mood-lifting benefits of being outdoors and interacting with nature. More than 80 per cent of regular riders say their hobby makes them feel 'quite a lot' or 'extremely' cheerful, relaxed, happy or active, University of Brighton researchers have found.
Get gardening for an hour or so
Tackle that heavy landscaping work and you'll have burned off at least 500 calories after an hour.
Raking and bagging leaves for just over an hour will burn off a similar amount. Or you could spend two hours digging, shovelling or mowing the lawn.
As well as having a tidy garden at the end of it, you'll improve your mental health, brain function and hand dexterity, says a recent study by the American Society for Horticultural Science.
How gardening keeps you fit
Spend the afternoon shopping
You'll have burned off around 500 calories after three hours of walking round the shops at a leisurely pace – but you can boost that amount by using the stairs instead of the lift or walking up the escalator. Then you can treat yourself to a new pair of shoes.
Try belly-dancing for two hours
As well as burning off at least 500 calories, you'll have toned your stomach, given your confidence a boost, had fun and probably made new friends.
Belly-dancing not for you? You'll get similar benefits from other dance forms. A 30-minute street, swing or contemporary dance class burns more calories than running, cycling or swimming, according to a University of Brighton study.
Your easy guide to getting into dancing
Have a five-hour-long kiss
Kissing can burn up to 100 calories per hour. You might have sore lips by the time you've hit 500 calories – but you'll have released a wealth of stress-busting hormones and given your facial muscles a good workout, too.
Kissing for a longer, healthier life
Go kayaking or canoeing for 90 minutes
It may not an activity you've considered before – but paddling is a low-impact exercise that's suitable for all ages. Aside from burning calories, you'll boost your upper body strength, cardiovascular fitness and mental health.
In an Australian study, people who'd completed a 12-week kayaking course experienced enhanced feelings of self-worth, confidence and adequacy.
Go bowling for two hours
A couple of hours spent crown green or ten pin bowling will burn around 500 calories – as well as give you a low-impact, full-body workout and improve your hand-eye coordination. Try crown green bowling and you'll also make new friends and reap the benefits of exercising in the open air, of course. Find a club near you at www.bowlsengland.com.
Do the ironing for four hours
Yes, it's dull – but there are benefits. You can catch up on your favourite TV show while you're doing it. And surely there'll be nothing left to iron by the time you've finished.
Finally, a quick word about calories: the amount you'll burn in any given time depends on a range of factors, including your age, size and activity levels. So the figures given above are only an approximate guide.