Those wanting to stop the main arteries to the heart from stiffening up need to exercise at least four to five times each week, according to a new report.

Researchers at the Institute for Exercise and Environmental Medicine (IEEM) in Texas, US examined the effect of different doses of lifelong exercise (those who had exercised regularly for more than 25 years) on arterial stiffening – a hallmark of vascular aging in older adults.

The study – called The Effect of Lifelong Exercise Frequency on Arterial Stiffness –found that those who exercised four to five days a week had preserved "youthful vascular compliance", especially in the large, central arteries.

Two or three exercise sessions a week were also beneficial – but only kept some arteries healthy, the study of 100 people in their 60s found.

The researchers said any form of exercise reduced the risk of heart problems, but that the right amount of exercise at the right time in life could reverse the ageing of the heart and blood vessels.

"Given the importance of vascular stiffening to health and clinical outcomes with human aging, it is important to develop strategies to forestall age-related CV diseases," said Dr Benjamin Levine, lead author from the IEEM.

"Exercise training is one approach. However, the minimal and/or optimal dose of

exercise training to preserve or improve vascular structure and function with human aging has yet to be clearly established.

"The present findings constitute an important step in this process by demonstrating the minimal frequency of lifelong exercise required to preserve compliant central arteries in older age.

"Importantly, this minimum exercise frequency is consistent with and strengthens current recommendations for weekly physical activity – 150 minutes each week."

The study was published in The Journal of Physiology this month. To download and read the full report, click here.