A growing body of research suggests that many people may not need hours in the gym to dramatically improve their health. According to scientists at the Norwegian University of Science and Technology, just 30 minutes of high intensity exercise per week may significantly improve cardiovascular health, reduce the risk of disease, strengthen the brain, and even extend lifespan.
At the center of this research is Ulrik Wisløff, a professor at NTNU and head of the Cardiac Exercise Research Group, known as CERG. For years, Wisløff and his colleagues have studied how exercise intensity affects human health. Their findings are reshaping how some scientists think about fitness.
“The biggest reported challenge regarding exercise is lack of time. But with intense, short workouts, this is no longer a valid excuse,” Wisløff said.
The 30 Minute Breakthrough
For decades, public health officials recommended at least 150 minutes of moderate exercise per week, with even more considered ideal. But Wisløff’s research suggests that much smaller amounts of exercise may still produce major benefits if the intensity is high enough.
Researchers say just 30 minutes of high intensity exercise spread throughout the week can improve health. That works out to about 4.5 minutes per day or roughly 10 minutes every other day. The key is not the duration but the intensity. People should push themselves hard enough to become noticeably out of breath.
Scientists recommend reaching approximately 85 percent of maximum heart rate. However, Wisløff says people do not need sophisticated equipment to judge effort. If someone can only speak in short sentences during exercise and cannot comfortably sing or carry on a long conversation, they are likely working hard enough.
The exercises themselves do not need to be extreme. For some people, a brisk uphill walk may be sufficient.
“Your own personal fitness level determines what gives you a high heart rate,” Wisløff explained. “If you are not very fit, simply taking a brisk walk may be enough.”
He also pointed to short interval sessions such as 45 seconds of effort followed by 15 seconds of rest, Tabata workouts with 20 second bursts, and the popular 4×4 interval method as highly effective ways to increase oxygen uptake.
The Massive Study Behind the Claims
One reason the findings have attracted so much attention is the scale of the research. In 2006, CERG conducted a major study using health data from 60,000 people in Norway. The results showed that strong cardiovascular fitness dramatically lowered health risks.
“Cardiovascular fitness is the best indicator of current and future health,” Wisløff said. “Good cardio fitness reduces the risk of over 30 lifestyle diseases as well as premature death by 40 to 50 percent.”
The studies did not stop there. Researchers later analyzed data from more than half a million people in Asia while studying a new system called Activity Quotient, or AQ. The findings showed a strong relationship between higher exercise intensity, improved cardio fitness, and lower mortality rates.
What Are AQ Points?
One of the newer concepts developed by NTNU researchers is AQ, short for Activity Quotient. Unlike traditional exercise tracking systems that mainly count steps or total workout time, AQ focuses on exercise intensity through heart rate.
AQ points are earned whenever physical activity raises the heart rate enough to make someone slightly out of breath. The harder the heart works, the faster AQ points accumulate.
Researchers found that people who reached at least 25 AQ points per week significantly lowered their risk of lifestyle diseases. The strongest benefits appeared at 100 AQ points or higher.
With an average intensity level of around 80% of your maximum heart rate, most people will earn around two AQ points every three minutes. A rule of thumb, for a 63 year old, the estimated maximum heart rate is approximately:
Scientists at NTNU and CERG developed the AQ algorithm using population data from five countries, including Norway. The score can be tracked through the Mia Health app, which works with heart rate monitors but also allows manual activity entry.
How Exercise Changes the Brain
Perhaps the most striking findings involve the brain. Wisløff and fellow researcher Atefe R. Tari have become major advocates for “micro workouts” because of their potential neurological benefits.
“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,” Tari said.
In research published in the medical journal The Lancet, scientists reviewed evidence from both human and animal studies. They found that exercise improves blood flow, reduces inflammation, strengthens immune function, increases brain plasticity, and stimulates the release of protective molecules in the blood. These are all processes that weaken with age and contribute to dementia and cognitive decline.
The researchers concluded that even small amounts of high intensity exercise may reduce dementia risk by up to 40 percent.
“We believe it’s time for health authorities to provide clearer advice on how important exercise is for the brain,” Wisløff said. “Even small doses of high intensity activity equivalent to brisk walking where you can’t sing can reduce the risk of dementia by up to 40 percent.”
Tari emphasized that the message should encourage people who feel overwhelmed by traditional fitness recommendations.
“A little is better than nothing and it’s never too late to start,” she said.
A New Way to Think About Exercise
The NTNU researchers believe current public health messaging may unintentionally discourage people by making exercise seem too time consuming. Wisløff says between 50 and 70 percent of people fail to meet current exercise recommendations.
That is why Wisløff and Tari are pushing for a shift toward “microtraining,” which involves brief but intense bursts of exercise incorporated into daily life. Their research suggests the body responds more strongly to intensity than duration.
“Exercise is cheap, accessible and has no side effects,” Tari said. “It should be considered a first-line measure to preserve brain health.”
The message from the Norwegian researchers is surprisingly simple. You do not necessarily need endless hours on treadmills or complicated workout programs. A few minutes of intense movement several times a week may be enough to improve your heart, strengthen your brain, reduce disease risk, and potentially add years to your life.
