How Much Exercise Does Your Heart Actually Need?

A large observational study published in the British Journal of Sports Medicine in May 2026 found that the exercise volume associated with meaningful reductions in cardiovascular risk is far higher than current public health guidelines recommend — while independent experts warn the finding should not become a new prescription.

What the UK Biobank Data Showed About Exercise and Cardiovascular Risk

Researchers tracked more than 17,000 British adults aged 40 to 69 enrolled in the UK Biobank study. Participants wore wrist accelerometers for a week to capture their activity levels objectively, and completed a cycling test to estimate baseline cardiorespiratory fitness (VO2 max). Over a median follow-up of eight years, the team recorded more than 1,200 cardiovascular events including heart attacks, strokes, atrial fibrillation, and heart failure.

Meeting the standard WHO and NHS recommendation of 150 minutes of moderate-to-vigorous physical activity per week was associated with an 8 to 9 percent reduction in cardiovascular risk compared with doing less. That is a meaningful benefit — but a modest one relative to what higher volumes appeared to confer. Participants who logged between 560 and 610 minutes of moderate-to-vigorous activity each week — roughly 10 hours, or three to four times the guideline — were associated with a risk reduction exceeding 30 percent. Only about 12 percent of study participants reached that threshold.

The chart below shows how the observed cardiovascular risk reduction scaled across three exercise-volume benchmarks identified in the source material.

Why Starting Fitness Level Changes How Much Exercise You Need

The study identified a secondary pattern that has clearer practical implications than the headline figure: your baseline cardiorespiratory fitness changes how hard you have to work to achieve the same relative benefit.

According to the research described by The Guardian, the least fit participants needed 30 to 50 more minutes of exercise per week than the most fit participants to achieve equivalent cardiovascular risk reductions. The difference was most visible at the 20 percent risk-reduction mark: people in the lowest fitness tier needed around 370 minutes per week to reach it, while those in the highest fitness tier needed roughly 340 minutes. That 30-minute gap is relatively narrow in absolute terms, but it suggests that people starting from a low fitness baseline face a steeper initial climb — a finding that may matter when designing public health programs or clinical referrals.

The chart below compares the two fitness groups at the 20% risk-reduction threshold.

Why Experts Are Pushing Back on the 10-Hour Figure

The study's authors described the current 150-minute guideline as offering a "modest safety margin" rather than optimal protection. But independent researchers drew a sharper line between what the data shows and what it should communicate publicly.

Professor Aiden Doherty at Oxford, quoted by Scientific American, argued that framing 10 hours a week as a target is "not a sensible public health message" and risks discouraging people who are currently sedentary. His position — that "every move counts" and the primary message should be that 150 minutes is already highly beneficial — reflects a genuine tension in exercise science communication: dose-response data showing higher benefits at higher volumes does not automatically translate into population-level advice.

There is also a methodological limit to keep in mind. This was an observational study. Participants were not randomly assigned to exercise at different volumes; they were tracked as they lived their lives. That means the data cannot rule out reverse causation — people with better underlying cardiovascular health may naturally be more active, which would inflate the apparent benefit of high exercise volumes. The researchers used accelerometers to measure activity objectively, which is more reliable than self-reported data, but the design constraint remains. As the authors acknowledged, the association between high exercise volumes and lower risk does not by itself establish that more exercise caused the better outcomes.

For most adults, the practical takeaway from the research is narrower than the headline suggests: meeting the 150-minute guideline is clearly worthwhile, and there appears to be a meaningful gradient of benefit beyond it — but the data does not support treating 10 weekly hours as a new universal target.