Have you recently carried heavy shopping bags up a few flights of stairs? Or run the last 100 metres (330 feet) to the station to catch your train? If you have, you may have unknowingly been doing a style of exercise called high-intensity incidental physical activity.
Our paper, published today in the British Journal of Sports Medicine, shows this type of regular, incidental activity that gets you huffing and puffing is likely to produce health benefits, even if you do it in 30-second bursts, spread over the day.
In fact, incorporating more high intensity activity into our daily routines – whether that's by vacuuming the carpet with vigour or walking uphill to buy your lunch – could be the key to helping all of us get some high quality exercise each day.
And that includes people who are overweight and unfit.
What is high intensity exercise?
Until recently, most health authorities prescribed activity lasting for at least ten continuous minutes, although there was no credible scientific evidence behind this.
This recommendation was recently refuted by the 2018 US Physical Activity Guidelines Advisory Report. The new guidelines state any movement matters for health, no matter how long it lasts.
This appreciation for short episodes of physical activity aligns with the core principles of high intensity interval training (HIIT).
HIIT in a hugely popular regimen involving repeated short sessions, from six seconds to four minutes, with rests from 30 seconds to four minutes in-between.
Among a range of different regimens, we consistently see that any type of high intensity interval training, irrespective of the number of repetitions, boosts fitness rapidly and improves cardiovascular health and fitness.
That's because when we regularly repeat even short bursts of strenuous exercise, we instruct our bodies to adapt (in other words, to get fitter) so we're able to respond better to the physical demands of life (or the next time we exercise strenuously).
The same principle is at play with incidental physical activities. Even brief sessions of 20 seconds of stair-climbing (60 steps) repeated three times a day on three days per week over six weeks can lead to measurable improvements in cardiorespiratory fitness.
This type of fitness indicates how well the lungs, heart, and circulatory systems are working, and the higher it is the lower the risk for future heart disease is.
Achievable for everyone
The main reasons people don't do enough exercise tend to include the cost, lack of time, skills, and motivation.
Exercise regimens like high intensity interval training are safe and effective ways to boost fitness, but they're often impractical. People with chronic conditions and most middle aged and older people, for example, will likely require supervision by a fitness professional.
Aside from the practicalities, some people may find back-to-back bouts of very high exertion overwhelming and unpleasant.
But there are plenty of free and accessible ways to incorporate incidental physical activity into our routines, including:
replacing short car trips with fast walking, or cycling if it's safe
walking up the stairs at a fast pace instead of using the lift
leaving the car at the edge of the shopping centre car park and carrying the shopping for 100 metres (330 feet)
doing three or four "walking sprints" during longer stretches of walking by stepping up your pace for 100-200 metres (330 - 600 feet) (until you feel your heart rate is increasing and you find yourself out of breath to the point that you find it hard to speak)
vigorous walking at a pace of about 130-140 steps per minute
looking for opportunities to walk uphill
taking your dog to an off-leash area and jogging for 30-90 seconds alongside the pup.
This type of incidental activity can make it easier to achieve the recommended 30 minutes of physical activity a day. It can also help boost fitness and make strenuous activity feel easier – even for those of us who are the least fit.