Short on Time? A Little More Intensity May Go a Long Way

By Maureen Farrar

There are days when a full workout simply isn’t going to happen.

Your schedule gets crowded. You have 15 minutes instead of 45. The walk gets cut short. Or you manage a little movement here and there but nothing that feels substantial enough to call a workout.

It’s easy to assume those small efforts don’t count. But new research suggests there may be another way to think about the movement you manage to fit into your day: It’s not only how much you move that matters. How hard you move may matter, too.

In a large study of adults with an average age of nearly 62, researchers found that a greater proportion of vigorous physical activity was associated with lower risks of eight major chronic diseases and death from any cause, even after accounting for how much physical activity people accumulated overall.

That’s an important distinction. More movement is still good. But occasionally turning up the intensity may offer benefits that simply adding more minutes doesn’t provide on its own.

It’s Not Just How Much You Move

Physical activity recommendations have traditionally been expressed in minutes: Adults should aim for at least 150 minutes of moderate-intensity aerobic activity or 75 minutes of vigorous activity each week, along with muscle-strengthening activity at least two days a week.

Those targets haven’t changed. But researchers are increasingly interested in another part of the equation: intensity.

In the study, recently published in European Heart Journal, researchers analyzed activity data from 96,408 adults participating in the UK Biobank. The group had an average age of nearly 62, and 56% were women. Participants wore wrist accelerometers, allowing researchers to objectively measure their movement rather than relying solely on people to remember and report how much they exercised.

Researchers then examined the relationship between physical activity and the development of eight chronic conditions, including major cardiovascular events, atrial fibrillation, type 2 diabetes, inflammatory diseases, chronic respiratory disease, chronic kidney disease and dementia—as well as death from any cause.

But they weren’t simply asking whether the most active people were healthier.

They wanted to know whether the intensity of that activity mattered independently of the total amount of movement.

It did.

More Intensity Was Associated With Lower Risk

Researchers looked at the percentage of participants’ physical activity that qualified as vigorous. As that percentage increased, risk generally decreased across all eight diseases and all-cause mortality.

Participants whose vigorous activity made up more than 4% of their total physical activity had a 29% to 61% lower risk of the outcomes studied compared with participants who accumulated no vigorous physical activity, even after researchers adjusted for their overall activity volume.

In other words, the association wasn’t explained simply by the fact that people doing vigorous activity were moving more overall.

The researchers also found that the relative importance of intensity and total activity differed depending on the health outcome.

For cardiovascular events, atrial fibrillation, chronic respiratory disease and dementia, intensity appeared to have a stronger relationship with risk than total activity volume. The same was especially true for immune-mediated inflammatory diseases.

For type 2 diabetes, metabolic dysfunction-associated steatotic liver disease, chronic kidney disease and all-cause mortality, both intensity and total movement appeared to make important contributions.

The takeaway isn’t that the amount you move suddenly doesn’t matter. It’s almost the opposite: both pieces matter, but they may not be interchangeable.

Related: Pressed for Time? Try One of These 20-Minute Workouts

What Does “Vigorous” Actually Mean?

Before you picture sprints, burpees or an all-out HIIT workout, there’s an important distinction to make: Intensity is relative.

Vigorous activity is generally movement that noticeably increases your breathing and heart rate. You might be able to say a few words, but carrying on a comfortable conversation would be difficult.

What produces that response will be different for everyone.

For one person, it might mean running up a hill. For someone else, it could be walking briskly uphill, climbing stairs, cycling faster for a minute or increasing the pace or resistance on a cardio machine. Your current fitness level, age, health and mobility all affect how hard a particular activity feels.

And vigorous doesn’t have to mean high impact. You can increase effort on a bike, rower, elliptical or while swimming without running or jumping.

Why Intensity May Matter

When you ask your body to work harder, even briefly, several systems have to respond.

Your heart beats faster to deliver oxygen-rich blood to working muscles. Your breathing increases. Your muscles demand more oxygen and energy. Repeated over time, those challenges can improve cardiorespiratory fitness, including VO2 max, a measure of how effectively your body can take in and use oxygen during exercise.

Higher-intensity exercise may also influence metabolic health, blood-vessel function and inflammatory processes, all of which could help explain some of the associations researchers observed.

But it’s important to keep the findings in perspective. This was an observational study. It can show an association between a greater proportion of vigorous activity and lower disease risk, but it can’t prove that increasing vigorous activity directly caused those reductions.

What it does add to the evidence is another reason to consider intensity as part of a well-rounded approach to fitness.

Related: Women Are More Likely to Put Fitness on the Back Burner

Find Small Opportunities to Turn Up the Effort

You don’t necessarily need another workout to experiment with intensity.

Think about the movement already built into your day and where you might safely increase the effort for a short period.

Pick up your pace during part of your walk. Take the stairs a little faster. Add a hill to your usual route. Increase the resistance on your bike. Push the pace for 30 or 60 seconds during a cardio session before returning to an easier effort.

You can also bring the same idea into a structured workout by occasionally choosing intervals or conditioning sessions that deliberately challenge your cardiovascular system.

The goal isn’t to make every workout harder. In fact, it shouldn’t be. Lower-intensity movement, strength training, mobility work and recovery all serve different purposes, and your body needs a balance of stress and recovery to adapt.

Think of intensity as another tool in the toolbox, not a replacement for everything else.

And if vigorous exercise isn’t appropriate for you right now, movement still counts. Walking, strength training, yoga, swimming and other forms of physical activity provide benefits whether or not they leave you breathless.

Make Some of Your Minutes Count Differently

Perhaps the most useful message from this research isn’t that we should all exercise harder.

It’s that how we use some of our active minutes may matter alongside how many active minutes we accumulate.

Some days you’ll have time for the full workout. Other days you won’t. And across a week, there will be room for hard efforts, easy movement, strength work and recovery.

You don’t have to turn every walk into a power walk or every workout into a sweat session. But when your body is able and the opportunity is there, occasionally picking up the pace enough to challenge yourself may be worthwhile.

Because when it comes to building health for the long haul, more movement matters, but sometimes, a little more effort matters, too.

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