From 45 Minutes to 40 Seconds: How HIIT Can Transform Your Workout

The BBC’s recent airing of ‘The Truth About Getting Fit’, revealed some interesting findings on just how little exercise may be needed in order for it to be significant. The show followed six office workers leading sedentary lifestyles, and gave them the opportunity to hop on an exercise bike. Each participant, led by presenter Michael Mosley, began the experiment by testing their baseline oxygen use, as well as the glycogen stores in their muscles. Using these markers, the show’s research team set out to find just how much their six subjects could improve on their fitness.

The experiment was simple. After an initial warm-up, each office worker was told to peddle as hard as they could, but just for 20 seconds. After a short break, they repeated that 20-second interval. This amounted to only a total of 40 seconds of high intensity exercise, which they repeated three times a week for five weeks. The results were relatively significant for a group of people who had never been exposed to high-intensity interval training.

Let’s take a look at the numbers. After just one cycling session, the researchers found glycogen levels had dropped up to 24 percent. This significant drop in glycogen is unique to cycling and HIIT. No other form of exercise can compete. Glycogen, however, was not the only notable result from this trial. Each participant experienced huge jumps in oxygen levels: on average, they increased their oxygen levels by 11 percent. One participant even saw a 14 percent increase. You can’t argue with that kind of data. And for those of us who have been cycling for years, we already innately knew the difference our lifestyle can make. Now we have the results to back it up.

To put the results in perspective, according to researchers from Sheffield Hallam, if you wanted to see the same kind of numbers from a traditional long distance run, you would need to run for 45 minutes instead of one of these 40-second sessions.

According to the lead scientist, Niels Vollaard, who lead the research, a workplace setting is appropriate for this form of exercise. “The total time-commitment of our protocol is just 3 x 10 minutes per week (including warm-up), the exercise does not produce a lot of heat so people do not sweat (I.e. no need to wear exercise kit or have a shower afterwards), and the exercise is associated with manageable ratings of perceived exertion. This means that our protocol removes a lot of common barriers to exercise”.



Less understood, but possibly more compelling for employers, is the energising effect of such short but intense bursts. You may leave your desk to do your HIIT session feeling lethargic and unenthused but you can be pretty sure that when you get back to your desk you would be awake and invigorated.