How much exercise do you need to protect your heart as you age? New study reveals the answer - and it's not what you might expect

Moderate exercise includes activities like walking, swimming workouts, cycling, and even gardening. For years, health bodies have been recommending all adults do at least an hour and a half of it every week, combined with regular strength training.

This one-size-fits-all approach needs to be reconsidered, say scientists who led a study published recently in the British Journal of Sports Medicine. The researchers reviewed how much exercise we need to do to significantly reduce heart attack or stroke risk, and found that many more than 150 minutes are needed to see a positive impact on heart health.

The team's results showed a 30% reduction in risk among those who did moderate-to-vigorous-intensity exercise for 560 to 610 minutes per week. That's about nine to 10 hours every week, or at least an hour and a half every day. It's a lot more than the current public health recommendations.

Researchers at Macao Polytechnic University in China investigated how physical activity and cardiorespiratory fitness, measured through estimated VO2 max, were associated with disease risk. The analysis used results from 17,088 people with an average age of 57 enrolled in the UK Biobank study between 2013 and 2015. They all wore a fitness tracker for seven days to record their physical activity and completed a cycling test to estimate their VO2 max.

The experts also looked at lifestyle habits such as smoking, alcohol intake, diet, body mass index, resting heart rate, and blood pressure.

The team found that adults who exercised for 150 minutes per week had an 8 to 9% lower cardiovascular risk across all fitness levels. However, the substantial protection (30%) was associated with a much higher level of activity. Just 12% of the participants reached that level of exercise.

A 20% reduction in the risk of cardiovascular events was associated with 370 minutes of moderate-to-vigorous exercise per week among those with the lowest fitness. That's about six hours. Those among the fittest in the group could do 30 minutes less per week and achieve the same 20% reduction, as their VO2 levels were naturally higher.

VO2 max measures how efficiently the heart and lungs work together to deliver oxygen to your muscles. VO2 max levels will naturally decline with age, as our lean muscle mass decreases and muscles work less efficiently.

Do we really need to do 9 hours of exercise a week?

The study shows that at least nine hours of exercise a week has a significant and positive impact on heart health. However, it's important to note that we're talking about moderate-intensity exercise here, says woman&home's digital health editor and fitness instructor, Grace Walsh.

"You can do moderate-intensity exercise outside of a typical workout. It would be very unusual for a regular person with a full-time job to manage nine hours of dedicated exercise every week," she says.

"You can meet this requirement with simple adjustments to your routine. Spend more time moving in your day. For example, if you normally take the bus to the train station in the morning, walk there instead. Taking the stairs at the office will raise your heart rate for a few minutes, more than using the lift would. Spend an afternoon gardening, painting, or tidying up. You'll be surprised how much your heart rate increases and stays in this important zone with these everyday activities," she says.

"Every little bit helps, and the easier and more enjoyable you can make movement, the more likely you are to do it."

Moderate intensity is about 50 to 70% of your maximum heart rate (220 minus your age), so try to stay in this zone as often as possible. "If you have a fitness tracker, you can keep an eye on your heart rate with recorded workouts, active minute monitoring, and live readouts on your wrist," she says.

The study's researchers have also said they support the 150-minute recommendation as a reliable minimum target. They hope the study will motivate people to fit more physical activity into their daily routine.

The study's results were also limited by how the data was recorded. VO2 max was estimated through the on-wrist trackers. For more accurate results, proper tests would need to be done in a lab, where participants wear special masks to monitor oxygen consumption.

If you're new to exercise, speak to your doctor to confirm you can do it safely.