Exercise: How little is enough?

Published on 16 March 2021

We all know that exercise is good for us and that a lack of it is bad for our health. What is less clear however, is how much exercise is enough to derive health benefits?

A common question that I’m often asked, is ‘how little is enough?’, or, to put it another way, ‘what is the minimum amount of exercise I need to do in order to see some benefit?’.

When I respond by telling people that current physical activity guidelines recommend a minimum of 150-minutes of moderate-to-vigorous aerobic exercise per week and going no more than two consecutive days without (which in our currency equates to 30-minutes of swimming, jogging, or dancing every day of the working week), the next, somewhat predictable, question is ‘how on earth am I supposed to fit all of that into my schedule?’; I also receive more succinct and powerful replies…

This question is less easy to answer. In fact, many people find it pretty difficult to achieve the physical activity recommendations whilst juggling the competing priorities of everyday life.

Not only do a large proportion of people do little or no structured exercise, but there are also fewer opportunities today than yesteryear for ‘incidental’ physical activity – the small amounts of time spent moving around such as walking to the bus stop, taking the stairs to the office, and even doing the hoovering! These small snippets of physical activity quickly add up across the day and they actually play a really important part in keeping us healthy, independent to any structured exercise that we might do on top. 

Thinking about how our lifestyles have changed over the decades, it is clear to see that our rapidly advancing technology-driven societies have created environments conducive to prolonged periods of physical inactivity – how long have you been sat at your desk before reading this article?

Furthermore, the pandemic has led to a temporary closure of gyms and sports clubs and local and national restrictions have largely reduced opportunities for incidental physical activity.

Many of us will spend long hours sat in front a screen, followed by several more hours sat in front of the TV before the Groundhog Day alarm rings again tomorrow morning. Plus, owing to the pandemic we have seen a negative shift in physical activity and eating behaviour – remember the spontaneous upsurge in baking (and then eating) boredom-induced banana bread?

Large volumes of sedentary time are strongly associated with morbidity (poorer health) and early mortality in a dose-dependent manner. It’s well established that sedentariness increases your risk of long-term chronic conditions such as diabetes and cardiovascular disease, whereas regular physical activity reduces these risks and results in a myriad of other benefits such as improved psychological wellbeing and quality of life. Even if you’re a weekend exercise warrior, spending prolonged periods of time sedentary during the week is harmful, and your weekend exercise blow-out might not be enough to counteract the negative impact of sedentariness.

So, rather than simply promoting exercise (as many healthcare professionals do), it is important for public health and healthcare professionals to consider types of lower-intensity physical activity, because a large proportion of people require interventions that target sedentariness, and it is these inactive individuals who have the greatest health concerns and have the most to gain.

Physical activity is important for everyone, but for physical activity to be fully adopted and maintained at a population level, it is necessary to start with solid, achievable and positive behaviour routines. For those that do not currently exercise or struggle to meet the physical activity guidelines, exercise can be viewed as daunting or unachievable and its outright promotion can often discourage and intimidate. However, reducing sedentary behaviour and enabling lower-intensity physical activity is more likely to be viewed by many people as achievable and a logical starting point to building more solid behaviour routines.

So, how little is enough and how can you incorporate this into every-day life? There are emerging alternatives to the conventional notion of health-enhancing bouts of exercise. Research from our team has informed the development of new physical activity guidelines that now include specific recommendations to reduce and interrupt prolonged sitting: ‘breaking-up’ prolonged sitting with short bouts of low-intensity activity such as a walking. Importantly, research has shown that this strategy of accumulating physical activity in small bit-size chunks can achieve comparable and even superior health benefits as structured activity. Although, I would caveat this with saying that although current research shows some very promising results, this is a relatively new area of research and more work is needed to confirm initial findings.

In practice this can be something as simple as standing up and walking for five minutes every 45-minutes to an hour during the working day, or three 10–15-minute walking breaks – that’s easily 30-minutes of accumulated physical activity between 9 and 5. The best ‘bang for your buck’ is to ‘snack’ on higher-intensity exercise throughout the day – short and sharp periods of activity that get you breathless and struggling to hold a conversation – this could be anything from sprinting on the spot, quickly climbing the stairs a few times, or even skipping, for example. This form of activity is similar to High-Intensity Interval Training (HIIT) and is a time-efficient approach to exercise. It has the capacity to induce rapid physiological adaptations and has been shown to improve the structure and function of the cardiovascular system. What’s more, the benefits of this type of activity appear to be similar to those achieved with traditional long-duration moderate-intensity continuous exercise (i.e., your 30-minute daily jog).

So, how little is enough? Well, the key message is that incidental physical activity is important, and it should be incorporated into your day in whatever way is practical for you. Although more exercise is better than less, some exercise (even a little) is still better than none.