When GH decided to launch a fitness challenge, there was only one woman we could turn to. Because honestly, who doesn’t want just a tiny slice of Davina McCall’s irrepressible energy for themselves?

In October, Davina designed a 31-day programme of fun, feelgood movement for GH readers – no equipment, no gym, no pressure. Just five minutes of each movement every day with a mat and your favourite playlist.

She hasn’t exactly slowed her pace since then. ‘My workout today,’ she recently wrote on Instagram, beneath a video of her shadowboxing in leopard-print leggings. ‘I absolutely love a fight. I literally want to go and run a marathon now!’

Current health recommendations suggest exercising for at least 2.5 hours each week, with 5 hours considered even better. For many people, that target can seem overwhelming.

But research from the past two decades suggests the amount of exercise needed for meaningful health benefits may be much lower than many assume. According to researchers, just 30 minutes of high intensity exercise per week can improve health. That works out to roughly 4.5 minutes per day or about 10 minutes every other day. The important part is intensity. The activity needs to be strenuous enough to leave you noticeably out of breath.

If you use a heart rate monitor, researchers say your heart rate should reach about 85 percent of your maximum. However, special equipment is not necessary. A simple way to judge intensity is by how difficult it is to talk. You should still be able to speak in short sentences, but you should not be able to sing or carry on a continuous conversation comfortably.

Why Cardiovascular Fitness Matters

“The biggest reported challenge regarding exercise is lack of time. But with intense, short workouts, this is no longer a valid excuse,” said Ulrik Wisløff, a professor at the Norwegian University of Science and Technology (NTNU) and head of CERG, a research group that conducts research on the health effects of exercise.

Researchers say even a small amount of high intensity activity can improve cardiovascular fitness, which plays a major role in long term health.

“Cardiovascular fitness is the best indicator of current and future health. Good cardio fitness reduces the risk of over 30 lifestyle diseases as well as premature death by 40 to 50 percent,” explained Wisløff.

CERG first documented these effects in a 2006 study that analyzed health information from 60,000 people. Since then, additional large studies from Norway and other countries have reported similar findings.

Is It Better To Spread Workouts Out?

Would it be just as effective to do one intense 30 minute workout each week instead of several shorter sessions spread across multiple days?

“It is best to spread the sessions out a bit, because exercise also has an acute effect that lasts for one to two days, so that way you get the best of both worlds,” said Wisløff.

Researchers say blood pressure and blood sugar control improve for 24-48 hours after a workout that pushes you hard enough to become breathless for several minutes. Because of these short term benefits, experts recommend dividing exercise across two to four days per week whenever possible.

Short Interval Training Can Be Effective

That does not necessarily mean sprinting at full speed or using the highest resistance setting on an exercise bike.

“No. Your own personal fitness level determines what gives you a high heart rate. If you are not very fit, simply taking a brisk walk may be enough. Having said that, you need to walk fast enough that you get quite out of breath. You can then increase the intensity as your fitness improves. Short intervals are effective. For example, this could be bursts of 45 seconds with 15-second breaks. Or like in Tabata workouts, with intense 20 second intervals interspersed with 10 second breaks. Otherwise, 4×4 intervals are recognized as highly effective for increasing oxygen uptake,” Wisløff said.

Fitness Must Be Maintained

Can you compensate for skipping exercise this week by doing extra workouts the week before?

“No. Fitness is something you have to maintain. Cardio fitness and strength decline quickly when not maintained, especially as you get older,” said Atefe R. Tari, a researcher and head of CERG’s initiative on exercise and brain health.

Strength training is also considered important, particularly for middle aged and older adults.

“We know that strength training is important, especially for middle-aged and older adults. There is limited research on how strength training affects lifespan, but a HUNT study exploring this is due to be published soon,” said Wisløff.

The Trøndelag Health Study (The HUNT Study) is a long running population health study in Norway that has gathered health data for more than 40 years.

New AQ Measurement Tracks Exercise Intensity

Researchers have also introduced a new measurement system called AQ (Activity Quotient).

Unlike traditional activity tracking methods that focus mainly on steps or workout duration, AQ measures exercise intensity by monitoring heart rate. Researchers say this provides a more accurate picture of whether someone is active enough to improve health.

Scientists at NTNU and CERG developed the AQ algorithm using population data from five countries, including Norway.

AQ can be measured through the Mia Health app created by NTNU and Sintef through the spin-off company Mia Health. The app connects with heart rate monitors, although users can also manually enter activities if they are not wearing one.

How AQ Points Work

AQ points are earned whenever physical activity raises your heart rate enough to make you slightly out of breath. The harder your heart works, the faster AQ points accumulate.

Researchers found that people reaching at least 25 AQ points per week significantly lowered their risk of lifestyle related diseases. According to the researchers, the strongest health benefits appeared at 100 AQ points or higher.

Click here to read more about AQ.

In a study examining the relationship between AQ and health, researchers analyzed data from more than half a million people. The study found a strong connection between higher AQ scores, better cardiovascular fitness, and improved health outcomes:

Association between Activity Quotient and cause-specific mortality — A prospective cohort study of 0.5 million participants in Asia, Progress in Cardiovascular Diseases, March-April 2025

Exercise and Brain Health

Large studies also suggest exercise benefits the brain in addition to the body.

“Physical health and brain health are closely linked, and cardio fitness is key here as well. Exercise leads to the formation of new brain cells,” said Atefe R. Tari, who is head of a research group at CERG.

Tari helped lead a scientific study on exercise and brain health published last year. The paper became one of the most widely read articles in The Lancet in 2025.

Researchers Push for “Micro Workouts”

Wisløff and Tari are now encouraging Norwegian health authorities to revise the country’s official exercise recommendations, arguing that exercise intensity should receive greater emphasis.

The researchers also wrote the book ‘Mikrotrening’ (in Norwegian), which draws on research reviews showing that brief bursts of high intensity activity may provide greater health benefits than spending many hours each week doing low to moderate intensity exercise. (Captions)

“We need a new Dagfinn Høybråten to get the whole population on board with this,” said Wisløff, referring to the man who was the driver behind the introduction of the smoking ban in Norway.

“In my opinion, Høybråten is the politician who has done the most for public health in Norway since the Second World War,” said Wisløff.

“It usually takes 3 to 5 years to see the effects of implemented measures, and since we have general elections every four years, this is not easy to achieve. This should be a cross-party initiative because it would save Norway 2 to 4 health budgets per year, and could be used for prevention and in areas such as elderly care,” Wisløff said.

Researchers say Norway’s extensive long term health databases make it easier to evaluate how exercise policies affect public health over time.

“Norway could become a pioneer with regard to health benefits from micro workouts,” said Wisløff.

The article below is an excerpt from my newsletter: Well Enough with Harry Bullmore. To get my latest thoughts on fitness and wellbeing pop your email address into the box above to get the newsletter direct to your inbox.

Exercise is good for you. Brilliant, in fact, by nearly every objective measure. For this reason, the world is full of fit people telling less fit people to do more exercise – but this rarely works. Why?

There’s a quote I love from my chat with experienced trainer, author and all-round sensible chap Ben Carpenter.

“Fitness professionals are hardcore exercise enthusiasts who often don’t know how to empathise with people who are not also hardcore exercise enthusiasts.”

This causes a massive divide between those who exercise and those who don’t.

Those who exercise regularly (group A) often built this habit as a child. Exercising regularly is their default, they are good at it, it feels fantastic, and (as with anyone who has ever hit a dopamine goldmine) they are keen to encourage others to do it too.

But for those who don’t exercise regularly (group B), it doesn’t feel good or natural at first – quite the opposite, actually. This is especially true when a member of group A recommends they start with a high-octane exercise class or hardcore workout programme.

No one is in the wrong – we are all just playing the cards we have been dealt. But there is a solution: start where you are, not where you want to be.

To do this, it is important to realise there is no one-size-fits-all fitness plan. The same workouts will affect people differently depending on individual factors such as genetics, environment and training experience.

This means, when a fitness figure or influencer tells you, “You can look like me by doing exactly as I do,” you would do well to question it.

Instead, it’s best to find a fitness routine that meets you where you’re at. (I think this plan from coach Darren Ellis offers a good framework for getting started, alongside a few options to scale it to your specific needs.)

If you currently don’t do any exercise, adding any new healthy behaviours into your regular daily routine will likely see an uptick in your fitness fortunes. For example, an extra portion of fruit and veg, a walk or a short mobility session.

If you’re a seasoned runner or gym-goer wanting further fitness progress, you need to upgrade the intensity of your existing workouts. For example, quickening your paces during interval sessions or adding a few extra kilos to the barbell for your next set of squats.

In both situations, picking appropriate workouts for you and progressing them in line with your fitness levels is the key to long-term success.

It’s also worth noting that exercise doesn’t always feel good at first, especially if you bite off more than you can chew.

I remember listening to elite coach Chris Hinshaw describe a running session he did with a former professional powerlifter who wanted to learn how to sprint. Powerlifters are juggernaut figures who excel at lifting heavy barbells, but they are often less adept at moving their own bodies.

So, Hinshaw gave his client a beginner sprinting drill he knew the athlete could excel at. “The first bite of the apple has to taste good,” Hinshaw later explained. Spurred on by his early success, the motivated athlete continued to work on his sprinting.

Perhaps hypocritically, given the intro, I am now going to tell you that exercise does ultimately end up feeling inexplicably good. My recent interview with 47-year-old Irishman David Keohan reinforced this belief.

“In my 20s I was into art and music and drinking and smoking,” he told me. “I was obese and unhealthy, mentally and physically. Then you get to your 30s and your body says, ‘Hold on a second, we need to start doing something about this, kid’.”

So, he went and bought a pair of trainers, fending off questioning glances from the man behind the till. Within six months he had run his first marathon. In the next few years he became a world champion at lifting kettlebells. Then, during Covid lockdowns, he started lifting huge boulders in his garden and stumbled across the lost Irish culture of stone lifting (this is one of my favourite recent interviews).

“I got bitten by the bug of feeling good,” Keohan continues. “Before, I never knew what feeling good felt like, if that makes any sense? But once you start to feel good, it’s amazing, and you realise how bad you felt for the last 10 years.”

Now, you don’t have to lift 170kg stones in your back garden to get in shape. This is an extreme example. But it does pay to do something slightly challenging (for you) on a fairly regular basis – whether that’s a short walk or a gnarly workout.

Because eventually, I’m afraid to say, exercise does have a tendency of making you feel rather good.

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