In recent years fitness trends have swung from short snappy HIIT sessions, to clocking up kilometres in preparation for a marathon.
But which is best - short or long workouts?
YOU WANT FAT LOSS
Alternating between bursts of intense exercise with short rest periods gives you the same (if not more) health benefits of slow and steady cardio, but in a shorter amount of time.
Commonly known as High Intensity Interval Training (HIIT), the intense work periods are performed at roughly 80% to 95% of a person's estimated maximal heart rate and last anywhere from 5 seconds to several minutes in duration.
HIIT has become popular for its ability to bust a higher number of calories during the workout, but also for several hours after. This phenomenon known as "excess post-exercise oxygen consumption" or EPOC has you burning up to 15% more energy overall, making it ideal for fat loss.
But before you throw yourself into HIIT, make sure you have a good base level of fitness to avoid injury, and alternate hard workouts with strength and rest days to give your body ample time to rest and recover.
The winner: Short and intense workouts
YOU WANT STRENGTH GAINS
When training for strength (i.e. ability to increase force) quality over quantity matters. With a focus on compound moves, such as multi-joint exercises (think squats or lunges), you work more muscle groups in half the time.
Heavier weights, with low repetitions are key with longer rest periods in between exercises to maximise recovery. To avoid injury, you've got to make sure you have proper form and are lifting the appropriate weight. Seek professional advice from a personal trainer or exercise physiologist.
The Winner: short and intense workouts
YOU'RE A TOTAL BEGINNER
When you're just starting out it's important to build up your fitness slowly to allow your muscles, bones, heart and lungs to adjust. Push yourself too hard too soon and you run the risk of extreme soreness or injury, such as a stress fracture or extreme shortness of breath, bringing your fitness session to a grinding halt.
To avoid this, opt for 30 minutes of "moderate" intensity cardio (brisk walking or cycling). By moderate we're talking a slight but noticeable increase in breathing rate. Once you adapt and sense you've a built a base level of fitness, build it up the intensity and duration gradually, then adapt. Repeat.
The Winner: Short and low intensity
YOU WANT TO LIVE LONGER
A recent study, which tracked the physical activity habits of 63,591 adults over a 12-year period, found that the risk of death from any cause was about 30% lower among "weekend warriors" (people choose to fit their weekly physical activity into one or two sessions) compared with inactive adults.
And people who chose to walk briskly for 30 minutes on five days of the week had similar health benefits to those that chose to undertake one long walk of 150 minutes every week.
The winner: A tie. Any exercise of any duration is better than leading a sedentary life.
YOU'RE TRAINING FOR A SPECIFIC EVENT
Marathons, triathlons, obstacle courses and most sports games require endurance - that is the ability for your cardiovascular system to keep up with your chosen activity. During these events you'll likely be exercising for an average of 60-minutes, so longer workouts are necessary to make exercise more economical.
This is because more oxygen is being circulated and a larger number of capillaries can deliver oxygen to the working muscles. Just make sure to increase your mileage by no more than 10% each week and intersperse these workouts with strength training and rest days to optimise performance, recovery and prevent injury.
The Winner: Long workouts