How Much Is One Minute of Hard Exercise Worth? What a 73,000-Person Study Found

In a 2025 study of 73,485 adults who wore activity trackers, one minute of vigorous activity was linked to the same lower risk of death and disease as about 4 to 9 minutes of moderate activity, or about 53 to 156 minutes of light activity (Biswas et al., Nature Communications, 2025). Current guidelines count a vigorous minute as worth two moderate minutes, so the study suggests short, hard efforts count for more than we've been assuming. It's an observational study, so it shows a strong link, not proof of cause.

What did the study measure?

The researchers used UK Biobank data. Participants wore a wrist accelerometer around the clock for seven days, and the researchers then followed their health for an average of eight years. They compared how many minutes of light, moderate, and vigorous activity it took to get the same drop in risk for five outcomes.

The accelerometer counted every vigorous minute, not just workouts, so fast stair climbs and hurried walks counted too.

How is that different from the usual exercise guidelines?

Current guidelines treat one minute of vigorous activity as worth two minutes of moderate activity. That's why U.S. guidelines call for 150 to 300 minutes a week of moderate activity or 75 to 150 minutes of vigorous activity (U.S. Department of Health and Human Services). The authors note that the 1-to-2 ratio came mostly from studies where people reported their own activity. Measured with a device, vigorous minutes lined up with a much bigger drop in risk than that ratio assumes.

What are the study's limits?

It's observational, so it can't prove that vigorous exercise caused the lower risk. Healthier people may simply be more able to exercise hard, and the authors say they can't rule that out. Activity was measured for one week and assumed to represent the following years. Participants were UK Biobank volunteers with an average age of about 62, which may not match everyone.

So "science proved it" would be too strong. A fair summary: hard minutes appear to count for a lot.

What counts as vigorous activity?

Vigorous activity is effort hard enough that you can't say more than a few words without stopping for a breath. Moderate activity is when you can talk but not sing (CDC). Running, hard rowing, fast cycling, and the conditioning part of a CrossFit class usually count as vigorous. A brisk walk is usually moderate.

What does this mean for your training?

A few practical takeaways:

• Hard efforts are worth doing, even short ones. A 10- or 12-minute workout done at a genuinely hard effort counts for a lot, and your weekly total doesn't have to be long.
• Don't skip strength training. Guidelines also call for muscle-strengthening work at least two days a week, which this study didn't measure. A CrossFit class covers both.
• Move harder in daily life when it's easy to. Take the stairs quickly, walk fast, carry the groceries in one trip.
• Build up to it. If you've been inactive, start at a moderate effort and add harder efforts over a few weeks. A coach can scale the intensity to where you are.

How do I add vigorous exercise if I'm starting from zero?

Start with two or three coached classes a week at an effort you can manage, and let the coach scale the workout. Most classes include a short, hard piece, and you choose how hard to push it. If you live in Bryan–College Station, start your free week with five coached classes within nine days. For more on getting started, read what to expect your first week.

Sources

• Wearable device-based health equivalence of different physical activity intensities against mortality, cardiometabolic disease, and cancer — Biswas et al., Nature Communications, 2025
• Physical Activity Guidelines for Americans, 2nd edition — U.S. Department of Health and Human Services, 2018
• Measuring Physical Activity Intensity — Centers for Disease Control and Prevention