A few breathless minutes of exercise each week could have a far bigger impact on your health than most people realize.
As summer approaches, many people start thinking about getting back into an exercise routine. While most of us know that physical activity is good for our health, finding the time and motivation to start, and then stick with it, can be a challenge.
Current public health recommendations call for at least 2.5 hours of exercise per week, with 5 hours considered even better. For many people, however, that amount can feel difficult to fit into an already busy schedule.
Research conducted over the past 20 years suggests there may be another option. According to scientists, just 30 minutes of exercise per week can improve health, provided the activity is performed at a high intensity. That works out to about 4.5 minutes per day or roughly 10 minutes every other day. The key is pushing yourself hard enough to become noticeably out of breath.
If you use a heart rate monitor, researchers recommend reaching about 85 percent of your maximum heart rate. But no special device is required. A simple rule of thumb is that you should be able to speak in short phrases, yet be too breathless to sing or carry on a long conversation.
Cardiovascular Fitness Drives Many Health Benefits
“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.
According to Wisløff, even a relatively small amount of vigorous exercise can improve cardiovascular fitness, which is one of the strongest indicators of overall 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 this connection in a 2006 study involving health data from 60,000 people. Since then, numerous large studies from Norway and around the world have reached similar conclusions.
How Often Should You Exercise?
Is one intense 30-minute workout each week enough, or is it better to spread the exercise out?
“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 note that a single workout session that leaves you breathless for several minutes can improve blood pressure and blood sugar regulation for 24–48 hours afterward. Because of these short-term effects, spreading exercise across two to four days each week may provide the greatest overall benefit.
Short Intervals Can Be Highly Effective
Does high intensity exercise mean running at top speed or using maximum resistance 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.
The amount of effort needed varies from person to person. Someone who is less fit may reach the desired intensity with a brisk walk, while others may need more demanding exercise to achieve the same effect.
Fitness Needs Ongoing Maintenance
Can you make up for skipping workouts this week by exercising extra hard 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.
The same principle applies to strength training.
“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 collected health information over four decades.
AQ Measures Exercise Intensity, Not Just Activity
Researchers have also developed a new measurement system called AQ (Activity Quotient).
Unlike traditional measures that focus on steps taken or total minutes of exercise, AQ is designed to capture how intensely a person is exercising by tracking heart rate. According to researchers, those traditional measures do not always reflect whether someone is active enough to gain meaningful health benefits.
The AQ algorithm was created by NTNU researchers at CERG using data from population studies in five countries, including Norway.
To calculate AQ, users can use the Mia Health app developed by NTNU and Sintef through the spin-off company Mia Health. The app can connect to a heart rate monitor, but users can also manually enter activities if they do not have a monitor or forget to wear one.
What AQ Scores Mean
AQ points accumulate whenever your heart rate rises enough to leave you slightly out of breath. The harder your heart works, the more quickly points are earned.
Researchers report that people who reach at least 25 AQ points per week significantly lower their risk of lifestyle-related diseases. The greatest benefits are seen at activity levels of 100 AQ points or more.
In a study examining the relationship between AQ and health, researchers analyzed data from more than 500,000 participants. They found a strong association 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 Benefits the Brain Too
The advantages of exercise extend beyond physical health.
Large studies indicate that regular exercise can also support brain function and healthy aging.
“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 was among the researchers behind a study on exercise and brain health published last year. The paper became one of the most widely read articles in The Lancet in 2025. You can read a Norwegian SciTech News article about it here: Exercise helps improve how our brain ages.
Researchers Call for More Focus on Micro Workouts
Based on the growing evidence, Wisløff and Tari are urging Norwegian health authorities to reconsider current exercise recommendations. They argue that exercise intensity deserves far more emphasis.
The researchers have also written the book ‘Mikrotrening’ (in Norwegian), drawing on research reviews showing that short bursts of high-intensity physical activity can provide greater health benefits than spending many hundreds of minutes per 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.
Norway’s extensive long-term health databases provide a unique opportunity to evaluate the impact of public health measures over time and compare outcomes.
“Norway could become a pioneer with regard to health benefits from micro workouts,” said Wisløff.
References:
“Survival of the fittest? Peak oxygen uptake and all-cause mortality among older adults in Norway” by Atefe R. Tari, Daniel E. Brissach, Emma M.L. Ingeström, Javaid Nauman, Tristan Tyrell, Carl Foster, Kimberley Radtke, John P. Porcari, Stian Lydersen, Leonard A. Kaminsky, Jonathan Myers, Tara L. Walker, Jeff S. Coombes, Dorthe Stensvold and Ulrik Wisløff, 4 December 2024, Progress in Cardiovascular Diseases.
DOI: 10.1016/j.pcad.2024.11.004
“Temporal changes in cardiorespiratory fitness and risk of dementia incidence and mortality: a population-based prospective cohort study” by Atefe R Tari, Javaid Nauman, Nina Zisko, Håvard K Skjellegrind, Ingunn Bosnes, Sverre Bergh, Dorthe Stensvold, Geir Selbæk and Ulrik Wisløff, November 2019, The Lancet Public Health.
DOI: 10.1016/S2468-2667(19)30183-5
“A single weekly bout of exercise may reduce cardiovascular mortality: how little pain for cardiac gain? ‘The HUNT study, Norway’” by Ulrik Wisløff, Tom IL Nilsen, Wenche B Drøyvold, Siv Mørkved, Stig A Slørdahl and Lars J Vatten, 1 October 2006, European journal of cardiovascular prevention and rehabilitation.
DOI: 10.1097/01.hjr.0000216548.84560.ac
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