Harvard Heart Letter

Add stretches to your exercise routine

They can help you stay flexible and active enough to keep your heart in good shape.

It’s no secret that as you age, your body becomes less flexible. Your muscles aren’t quite as supple and your joints are little stiffer than when you were younger. As a result, getting regular, heart-protecting exercise may be more challenging.

That’s why stretching — the deliberate lengthening of muscles to increase flexibility and range of motion — can be especially helpful after middle age. Yet many people are confused about the different stretching techniques and the best time to do them, says sports medicine physician Dr. Adam Tenforde, assistant professor of physical medicine and rehabilitation at Harvard Medical School.

Take, for instance, the oft-heard advice about stretching before a workout. “In studies of athletes, there is no good evidence that stretching prevents injuries,” says Dr. Tenforde. In fact, doing static stretches (in which you adopt and hold a position) when your muscles aren’t warmed up may even cause an injury. If you haven’t been moving around much and then reach down to touch your toes, you could pull a hamstring (a muscle in the back of the thigh) because the muscle isn’t receiving a generous supply of blood and is therefore more vulnerable to a small tear, he explains.

Dynamic stretching

On the other hand, dynamic stretching — in which you move gently to stretch your muscles and loosen your joints — is a better choice before your workout. Examples include moves such as shallow side lunges (see photo at top of page) or arm sweeps. These moves generally involve multiple muscle groups from different parts of the body.

For moderate-intensity exercises such as brisk walking or swimming laps, simply starting your workout slowly is a perfectly fine warm-up, says Dr. Tenforde. Doing so will get blood flowing to your muscles and tendons and also help prepare your heart and lungs for a higher level of exertion.

Static stretching

The best time to do static stretching is after your workout, when your muscles are nice and warm. The increased blood flow to your muscles helps them elongate, which translates into greater flexibility. Having that greater ease and range of motion will likely encourage you to maintain your exercise routine.

After a brisk walk or jog, your hip or knee might feel a little tight. So it may feel good to do a “floor pretzel,” which stretches your buttocks, hip, and outer thigh (see photo below). For additional examples and information, see the Harvard Medical School Special Health Report Stretching: 35 exercises to improve flexibility and reduce pain (www.health.harvard.edu/str).

How often, how long?

The American College of Sports Medicine advises healthy adults to stretch or do other flexibility exercises (such as yoga or tai chi) that involve all major muscle-tendon groups — neck, shoulders, chest, trunk, lower back, hips, legs, and ankles — at least twice a week.

For best results, spend a total of 60 seconds on each stretching exercise. So, if you can hold a particular stretch for 15 seconds, repeating it three more times would be ideal. If you can hold the stretch for 20 seconds, two more repetitions would do the trick.

Dr. Tenforde, who is also director of Running Medicine for the Spaulding Rehabilitation Network, agrees that doing yoga can be a great way to increase your flexibility. Taking a class will guide you through a series of poses (called asanas) that alternately lengthen and relax the large muscles. Tai chi — an ancient Chinese practice that involves a series of low-impact, flowing movements — is somewhat like dynamic stretching but done in slow motion. Another option is a gentle water aerobics class, as the warm water and lower-gravity environment provide a comfortable venue for active stretching.

Dr. Tenforde is also a fan of foam rollers, which are small cylinders made of compressed foam. Although not technically a type of stretching, foam rolling helps loosen up fascia, the thin sheath of tissue that surrounds muscles. You lie with the roller beneath your legs, back, hip, or any sore spot and roll back and forth. The roller pushes against your body and provides resistance much like a massage.

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