Stretching is usually used to improve flexibility, reduce stiffness and help people move more comfortably. But new research suggests that regular stretching may also have benefits beyond the muscles and joints. It may help keep the arteries more flexible and potentially support cardiovascular health.

A recent systematic review examined whether stretching reduces arterial stiffness in adults. Arterial stiffness describes how well the large arteries expand and relax as blood is pumped through them. Healthy arteries are elastic and help absorb the pressure created by each heartbeat. As arteries become stiffer, the heart has to work harder and cardiovascular risk tends to increase.

Researchers commonly measure arterial stiffness using pulse wave velocity (PWV). Put simply, PWV measures how quickly the pressure wave created by the heartbeat travels through the arteries. The faster the wave travels, the stiffer the arteries.

What did the researchers study?

The researchers reviewed studies of adults aged 18 years and older and separated stretching into two types:

• Acute stretching — the effect of one stretching session.
• Long-term stretching — repeated stretching carried out regularly over several weeks.

Six studies involving 110 participants examined the immediate effects of stretching, while another six studies involving 159 participants investigated longer-term stretching programs. The long-term studies generally lasted between about four and 12 weeks.

This distinction is important because a single stretch may temporarily alter blood flow, while repeated stretching could potentially produce more lasting changes in the blood vessels.

One stretching session probably does little

The immediate effects were relatively small.

Across the studies, a single stretching session produced a small reduction in arterial stiffness, but this effect was not statistically significant. The overall effect size was −0.22.

In practical terms, therapists should not expect one stretching treatment to substantially change cardiovascular health.

There may still be temporary changes in circulation. Stretching a muscle can increase blood flow and create forces along the lining of blood vessels. This may stimulate the release of nitric oxide, a substance that helps blood vessels relax. But the evidence does not currently show that one stretching session produces a reliable reduction in arterial stiffness.

Regular stretching is more promising

The more interesting result came from people who stretched regularly.

Long-term stretching produced a large reduction in arterial stiffness, with an effect size of −1.02. The average reduction in PWV was approximately 0.94 metres per second.

That number is potentially important because a change of around 1 m/s in PWV has been regarded as clinically meaningful.

The researchers therefore suggest that the benefits of stretching may be cumulative. Repeated stretching may repeatedly stimulate the blood vessels, potentially improving endothelial function and, over time, producing structural changes in the arterial walls.

In simple terms:

One stretch may briefly influence blood flow. Regular stretching may gradually influence the health and flexibility of the blood vessels.

How much stretching might be needed?

The researchers examined whether different stretching programs produced different results.

Most of the programs used static stretches performed to the point of mild discomfort rather than pain. Individual stretches commonly lasted about 20–45 seconds, with approximately 30 seconds being typical. Sessions ranged from about 13 to 50 minutes.

Some patterns suggested that greater amounts of stretching might produce larger effects. Sessions lasting more than 30 minutes appeared more effective than shorter sessions, stretching at least five times per week appeared more effective than less frequent stretching, and supervised programs appeared more effective than unsupervised programs. However, these differences were not statistically significant, so they should not yet be regarded as proven dose-response relationships.

Based on the available studies and existing stretching guidelines, the authors provisionally suggested 30–50 minutes of stretching on five to seven days per week.

For therapists, this is best viewed as a research-informed starting point rather than a firm clinical prescription.

Why might stretching affect the arteries?

When a muscle and its surrounding tissues are stretched, the blood vessels passing through the area are also mechanically affected.

During stretching, blood flow can temporarily change. When the stretch is released, blood flow increases again. This change in flow creates shear stress along the inside of the blood vessels.

Shear stress can stimulate endothelial cells — the cells lining the blood vessels — to produce nitric oxide. Nitric oxide helps the vessel relax and widen.

If this response happens repeatedly over weeks or months, researchers suggest it could eventually influence the structure of the arterial wall itself. The current evidence therefore supports a plausible biological explanation for why regular stretching could reduce arterial stiffness.

What does this mean for therapists?

The findings broaden the way stretching might be viewed clinically.

Stretching should not simply be considered a method for increasing range of motion. Regular stretching may also provide a low-intensity cardiovascular stimulus, making it potentially useful for clients who find conventional exercise difficult.

This could be especially relevant for older adults, sedentary clients or people who cannot easily participate in moderate- or vigorous-intensity exercise.

Stretching also has practical advantages: it requires little equipment, can be performed almost anywhere and is relatively easy to incorporate into home programs. The studies of long-term stretching reported high adherence, and no adverse effects were reported in the interventions included in the analysis.

However, stretching should not be presented as a replacement for aerobic exercise, resistance training or medical treatment for cardiovascular disease. At this stage, it is more appropriate to regard stretching as a potentially useful additional strategy.

The evidence is promising, but still limited

This is the most important caution.

Although the reduction in arterial stiffness with regular stretching was large, the researchers rated the certainty of the evidence as low. The main problems were small study sizes and possible risk of bias. Only one of the six long-term studies had enough participants to meet the researchers’ estimated sample-size requirement.

The studies also involved relatively similar groups of participants, making it difficult to know whether the same effects occur across different ages, health conditions, ethnic groups and levels of cardiovascular risk.

Interestingly, the evidence for the immediate effects of stretching was rated moderate certainty, but the effect itself was small and not statistically significant. The stronger long-term effect was supported by lower-certainty evidence.

The take-home message

For therapists, the study provides an intriguing new reason to value regular stretching.

A single stretching session probably has little meaningful effect on arterial stiffness. Repeated stretching over several weeks, however, may substantially improve arterial flexibility.

Current research tentatively points towards relatively frequent stretching — perhaps 30–50 minutes, five or more days per week, with individual stretches held for around 30 seconds to mild discomfort.

But these numbers should not yet be treated as established clinical guidelines.

The bigger message is that stretching may influence more than muscles. When performed regularly, it may also provide a gentle stimulus to the vascular system. For clients who have difficulty undertaking conventional exercise, that possibility makes stretching particularly interesting — but larger, better-controlled clinical trials are still needed before cardiovascular benefits can be promised.