Isometric exercises - those that require engaging muscles without movement, such as wall sits and planks - provided the best results for bringing blood pressure down, a new study suggests.

Cardio, resistance training and HIIT workouts were also beneficial, but it turns out you can't beat staying still.

The discovery means it could be time to update the current exercise recommendations for preventing and treating high blood pressure, the researchers said.

The NHS webpage on preventing high blood pressure recommends adults do at least 150 minutes of moderate-intensity aerobic activity, such as cycling or fast walking, every week.

The researchers, led by academics at Canterbury Christ Church University in Kent, said current guidelines are based on "older data" and suggested it may be time to review them.

The academics found there were significant reductions in resting blood pressure following cardio; dynamic resistance training, such as squats, press ups and weights; high intensity interval training (HIIT); and combined training and HIIT.

But the largest reductions were seen after isometric exercise training.

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The study, published in the British Journal of Sports Medicine, saw researchers analyse 270 previous studies on exercise and blood pressure. The studies contained data on almost 16,000 people.

They examined the impact different exercises had on systolic blood pressure, when your heart pushes blood out, and diastolic blood pressure, the pressure when your heart rests between beats.

Further analysis showed the most benefit was seen among those who performed "isometric wall squats" and among runners.

What is high blood pressure?

For the average adult, high blood pressure is considered to be from 140/90mmHg (millimetres of mercury).

When a person's blood pressure is too high, it puts extra strain on blood vessels, heart and other organs, such as the brain, kidneys and eyes.

Persistent high blood pressure can lead to a number of serious health problems including heart attacks, strokes and vascular dementia.

While there are medications which can help, people can make a number of life-style changes to help bring their blood pressure down including regular exercise, losing weight, and cutting back on caffeine, alcohol and salt.