Best of all, many of these easy moves work to jump start a lagging metabolism so you continue to burn extra kilojoules throughout the day—even while you sleep! 

1. Swing those arms

Turn your walking into a kJ-torching workout by bending your elbows 90 degrees and pumping your arms as you stride. It not only automatically speeds up your pace but helps you burn up to 15% more kilojoules every time you work out. For proper pumping: Trace an arc from your waist to your chest as you swing. Your thumbs should come close to touching your waistband as your elbow goes backward. Also, make sure to keep elbows in and don't let hands cross past the middle of your chest (in front of your sternum). Too much side-to-side motion drags down your pace.

2. Pop in headphones

You can fight flagging energy with music: Working out to your favourite fitness playlist can help you to go up to 20% longer and burn more kilojoules, finds a study from West London's Brunel University. Music blocks fatigue, produces feelings of vigor, and helps you keep pace by synchronising your movements, says study author Costas Karageorghis, PhD.

3. Put on some weight

To really rev your kilojoule burn, it is not about the number of reps, but the size of the weights. Even when exercisers lifted identical volumes (such as 5kgs 10 times or 10kgs 5 times), those using the heavier dumbbells burned about 25% more kilojoules when they were finished. "Heavy weights create more protein breakdown in the muscle, so your body has to use more energy to repair and recover—that's how lean muscle tissue is built," says researcher Dr Anthony Caterisano. Bonus: working out with heavy weights even for as few as 3 to 6 reps increased exercisers' sleeping metabolic rate—the number of kiljoules burned overnight—by nearly 8%. That's enough to lose about 2.5kgs in a year, even if you did nothing else! 

4. Quench with cool water

A fresh-out-of-the-fridge water bottle may energise you for warm-weather exercise, finds a British study. Exercisers who drank refrigerated water (4°C) worked out about 25% longer than those who consumed the same amount of warmer water—and they said their exercise sessions felt easier too. Whether you're inside or out, sipping chilled water both before and during exercise may help keep your body temperature down and your energy up for maximum kilojoule burn. 

5. Break up your sets

Instead of performing 2 or 3 sets of a single exercise before moving to the next one, do a circuit: Complete just 1 set and then immediately move to the next exercise, repeating the circuit 2 or 3 times. When researchers had testers do either standard strength-training (3 sets of 6 exercises with 2 minutes of rest in between) or circuit-training (moving through a series of 6 exercises 3 times, with 30 seconds of rest in between), the circuit-trainers burned nearly twice as many kilojoules postworkout as the standard-style lifters. "Because your heart rate stays elevated longer after circuit-training, you continue burning fat as though you were still exercising," says researcher Anthony Caterisano.

6. Head outside

Trade the treadmill for trails. Besides the fresh air and better scenery, heading outside can give your workout a major boost. Research finds that exercisers burn 10% more calories when they walk or run outdoors than they do on a treadmill at the same speed. "You use more energy to propel yourself over the ground," explains fitness expert Jay Blahnik, "and pushing a little against the wind or other elements burns more kilojoules, too." 

7. Crank up the incline

If bad weather forces you indoors, challenge yourself on the treadmill. Crank up the incline to firm up your derriere and rev up your kilojoule burn by up to 60%. And when you come back down to earth, walking will feel easier.

To safely take your walks to the next level, follow these guidelines:

  • Don't lean. Maintain an upright posture; keep your shoulders over your hips; your hips over your ankles.
  • Start easy. Do a 5-minute slow walk and then a 10-minute brisk pace before adding your first hill.
  • Go 5 and 5. Alternate 5-minute hills with 5 minutes of level walking. Repeat as often as you like. Cool down for 5 minutes.
  • Inch up. You may only be able to walk a 1% incline initially. The key is to maintain the same speed during the hills as you do with no incline. Aim for a 5.5 kph speed, and keep your hills moderate; a 5% incline is a great goal, and go no more than 7%. (Steeper inclines put too much strain on your back, hips and ankles.)

8. Log at least 12 minutes

Any amount of cardio will burn kilojoules, but to really fight off kilos, you need at least 12 minutes (beyond a warm-up) of continuously moderate to high-intensity activity (where you're breathing somewhat hard) most days a week. That's the amount necessary to "create a training effect, which improves your body's ability to use oxygen and generate more fat-burning enzymes, such as lipase, so you can blast more fat during exercise and other activities all day," says exercise physiologist Chip Harrison.

9. Cut your workouts in half

Introducing short bouts of vigorous activity can speed up weight loss and cut your workout time by up to half or more. Australian researchers found that women who alternated just 8 seconds of high-intensity exercise with 12 seconds of low-intensity activity for 20 minutes, 3 times a week, slimmed down faster than steady-paced exercisers who worked out twice as long. Those who did intervals lost up to 8kgs, shrunk their bellies by 12% and their thighs by 15%, and gained, on average, 700gm of metabolism-revving muscle in 4 months—without dieting! Get started with these 20-minute interval workouts.

10. Don't skip stretching

Stretching keeps your muscles flexible, helping to prepare them for exercise and recover from the effort afterward. Skip the stretches, and you won't get nearly the benefits you should from aerobic exercise and resistance training. (Get started with these 3 feel-good stretches.) "Stretching helps you move freely during aerobic exercise, it enables your muscles to build more strength during weight training, and it helps keep muscles long and lean," says Sharon Willett, a physical therapist and sports trainer.