woman sweating in the gym after hiit class

12-minute bursts of exercise: the unexpected health benefits of short stints of intense activity

Posted by for Strong Women

A recent study has found that 12-minute bursts of exercise offers impressive health benefits. Here, a doctor explains how and why short workouts are so good for us. 

The myths that a workout should last an hour to be productive has been dispelled by the popularity of HIIT training – a type of workout that proves short periods of exercise can yield cardiovascular and muscular endurance results. These sessions might be more around the half an hour mark, but it turns out that you could save even more time on your training, as a new study by the Massachusetts General Hospital found that health benefits can come from just 12-minute bursts of intense exercise.

According to the study, this has to do with beneficial shifts in the levels of “metabolites” circulating in the body during and after a short stint of high-intensity exercise, which, simply put, are by-products of your metabolism.

In order for researchers to gauge and examine this, 411 men and women were asked to complete 12 minutes of vigorous exercise, and their metabolites were measured before and immediately after via a blood test. 

From the post-workout samples, “the research team detected favourable shifts in a number of metabolites for which resting levels were previously shown to be associated with cardiometabolic disease.” For example, after just 12 minutes of high-intensity exercise, there was an incredible 29% drop in levels of glutamate, “a key metabolite linked to heart disease, diabetes, and decreased longevity.” Levels of DMGV, “a metabolite associated with increased risk of diabetes and liver disease”, fell by a similarly impressive 18%.

Clearly, shorter bursts of intense exercise really can work wonders for your health, and training consistently in this manner has the potential to keep you in peak physical condition for longer.

There are, however, also more immediate benefits to working out in this way. We asked Dr Sarah Davies, a sports expert from Panacea Health, to expand on the “whys” and “hows” of the many short- and long-term benefits of 12-minute bursts of intense exercise. 

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What are the benefits of 12-minute bursts of exercise?

Dr Davies explains that the change in metabolites caused by shorter bursts of intense exercise is driven by the mitochondria, which are responsible for powering almost all of the cells in the human body.

She says that “when you challenge yourself in a workout, you ramp up the metabolic processes,” which “happens mainly because high-intensity training makes the cells produce more mitochondria.” This increase in what Dr Davies terms “mitochondrial density” has a lot of benefits, including reducing your risk of developing certain life-threatening diseases.

There are plenty of more localised benefits, too. For example, the “increased production of cellular mitochondria” makes your heart muscle more efficient, because you “need less oxygen to carry out the same exercise” as a result. Not only does this have a positive effect on your overall heart health, but it also means that you will be able to make progress faster than you would with longer periods of low or moderate-intensity exercise. 

The muscles throughout your body also feel the effects, with the boost to the muscle cells’ mitochondria helping you to build muscle faster, perform better, and reap the greatest possible health gains in the fastest possible time. 

How hard do you have to work for 12-minute bursts of exercise to be effective?

“You have to challenge your own individual exercise capability,” says Dr Davies, meaning that there isn’t a one-size-fits-all answer. High-intensity training should, however, “physically tire you out, with the benefit that overall time invested is low.”

It’s important to note, though, that “if you have any family or personal history of heart or vascular illness, you should ask your doctor to advise if this is the correct form of exercise for you.”

Sprinting
Short bursts of exercise: "high intensity training should physically tire you out."

What are the best forms of exercise to try in short bursts

If you want to give shorter bursts of exercise a try, then cardio workouts are the way to go. Dr Davies recommends “cycling, running, cross-training and swimming” in particular because these forms of exercise “use the large muscle groups throughout the body for maximum mitochondrial effect.” They are also all fairly accessible, “as the equipment is widely available and can be done at home or in the great outdoors.”

She also suggests aiming to do your short bursts of exercise two to three times a week in order to make the most of their many health benefits.

However, you will need to start off slow “and build your tolerance gradually to give your body time to adapt,” says Dr Davies. If you overdo it by pushing yourself too hard and too fast, you run the risk of injuring yourself, “which will prevent you from achieving your goals.” 

Follow @StrongWomenUK on Instagram for the latest workouts, delicious recipes and motivation from your favourite fitness experts. 

Images: Getty

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