A seven-minute workout – how hard could it be?

That was my first thought, anyway. But, to be honest, somewhere between thrashing out 30 seconds of high knees, followed by a burst of lunges, then a series of non-stop push-ups, I felt far less confident of finishing the express workout.

In fact, as the seconds counted down on the Scientific 7-Minute Workout app, I felt relieved I had not selected the Advanced option!

To briefly explain, I – like you – am time-poor, but I like to keep fit. So I decided to trial the internationally acclaimed New York Times workout designed to help you get fit – fast.

The full-body exercise program was released in 2014 and has since sparked a worldwide craze for short workouts. A few minutes browsing your app store will uncover express workouts for every pursuit from running programs, yoga, strength training, plyometrics and meditation.

The thing about a short workout is:

a) It’s appealing to professionals, parents and pen-pushers alike because, let’s face it, it’s hard enough finding time to think about exercise, let alone actually donning your Dri-FITS and doing it on a regular basis, right?

b) Apps like the Scientific 7-Minute Workout include a timer and audio cues to guide you through the brief session anywhere, at anytime, with no equipment needed; and

c) Short workouts promise to increase metabolism, increase bone density, burn hundreds of calories in a short time, build muscle, improve endurance and lift your mood. Research even shows exercising for 15 minutes a day can reduce your risk of cancer and add an average of three years to your life span.

So why wouldn’t you do short workouts?

On trial next, I found the PT in my Pocket app, designed by Melbourne trainer Colette McShane, aka The HIIT Mum.

Be careful not to overdo it.

I queued the Trim Tummy Ten workout – a specific abs and core session – and checked over the explanations for each exercise. Five minutes later, I was Russian Twisting my way into workout oblivion. I realised if I did actually do this on a regular basis I would, in fact, have abs of steel!

The thing about High Intensity Interval Training (HIIT) is that you alternate periods of high- and low-paced activity for a set amount of time. Usually a HIIT workout includes around 12 exercises, which are performed in 30-second bursts, with a short rest period between each. For the best results you should exercise at 80 per cent of your capacity.

The third short workout I decided to road test was one of US-based coach Jenny Hadfield’s 20-minute running workouts. I decided on a session that includes a 12-minute tempo run.

After a short warm-up, I ran at an easy pace for five minutes before dialling up the speed for 12 minutes. The key was to take myself just outside my comfort zone, but not end up in a mess on the footpath gasping for air. It was a close call!

The verdict?

There’s no doubt if you subscribe to short workouts like these, you will get fit in no time. But after years of hearing The Heart Foundation’s recommendation for at least 30 minutes of exercise per day, does working out for just seven, 10 or 12 minutes at a time really cut it?

Vanessa Gospel, a Sydney-based personal trainer at Fitness First, says no.

“But if you can only spare 20 minutes or less, ensure you are exercising at moderate- to high-intensity levels the entire time with very short ‘active recovery’ breaks (where the rest period is still a movement),” she advised. What’s more, know the risks.

“Smashing out short workouts prescribed by apps and online HIIT programs, can sometimes mean you sacrifice technique when trying to keep up with others or the app,” warned Gospel.

That can lead to injury and see you sidelined for weeks.

“Apps are not personalised to your training goals, body type or diet; you can also easily lose motivation as there is no one to keep you accountable.”

Harriet Edmund is a Melbourne-based freelance journalist.