Less fit people need more exercise for same heart health gains, study finds

Less fit people may need 30 to 50 minutes more exercise a week than fitter people for similar heart health gains, research suggests.

The study analysed data from more than 17,000 British adults in the UK Biobank study.

Participants, aged 40 to 69, completed a cycle test to measure baseline cardiorespiratory fitness, or how well the body uses oxygen during exercise.

They also wore a fitness tracker for a week to record their usual activity levels.

The adults were followed for an average of eight years, during which more than 1,200 cardiovascular incidents were recorded.

These included heart attack, atrial fibrillation, stroke and heart failure. Atrial fibrillation is an irregular heart rhythm that can raise the risk of stroke.

The NHS advises adults to do at least 150 minutes of moderate to vigorous physical activity each week, such as brisk walking, cycling or running.

The study found that meeting this guideline was linked to an eight to nine per cent lower cardiovascular risk.

The researchers said: “Given that large proportions of the population do not meet even this benchmark, the primary public health message remains straightforward: achieving 150 minutes per week of moderate to vigorous activity delivers meaningful cardiovascular protection regardless of fitness level.”

The analysis also suggested that higher activity levels were linked to further reductions in cardiovascular risk.

However, people with the lowest fitness levels needed around 30 to 50 extra minutes of exercise each week to achieve the same level of benefit as fitter people.

To achieve a 20 per cent reduced risk, the least fit participants needed to do 370 minutes of moderate to vigorous physical activity each week, compared with 340 minutes among those with the highest fitness levels.

For a reduction of more than 30 per cent, the least fit would need more than 10 hours, or 610 minutes, while the fittest would need just over nine hours, or 560 minutes.

The researchers said: “This finding highlights the steeper challenge faced by deconditioned populations.

“Current moderate-to-vigorous physical activity guidelines provide a universal but modest safety margin, whereas optimal cardiovascular protection may require substantially higher activity volumes.

“Future guidelines and implementation strategies may need to differentiate between the minimal moderate-to-vigorous physical activity volume required for a basic safety margin and the substantially higher volumes necessary for optimal cardiovascular risk reduction.”

The findings appear to challenge earlier research, which found that walking only 4,000 steps a day could still cut older people’s risk of early death by around a quarter.

But experts said recommending more than nine hours a week of exercise was “misguided”.

Aiden Doherty, professor of biomedical informatics at the University of Oxford, said: “We can’t give much weight to the figure of 560-610 minutes of exercise a week.

“Clearly there will be cardiovascular benefit for people who are able to do (more than) 1 hour 20 minutes of moderate-to-vigorous intensity physical activity a day but this is not a sensible public health message.

“The public should continue to aim for at least 150 minutes of moderate to vigorous intensity of physical activity a week; more is better; every move counts.”

Responding to the findings, a Sport England spokesperson said that increasing activity levels was vital for keeping people healthier for longer.

“Emerging research like this reinforces the importance of helping more people be active, more often.

“Sport England’s own research shows activity relieves healthcare issues for both individuals and the NHS, preventing 1.3 million cases of depression, 600,000 of diabetes and 57,000 of dementia.”