Is Exercise Safe for Myotonic Dystrophy?

If you have Steinert myotonic dystrophy (also known as myotonic dystrophy type 1 or DM1), you might wonder if exercising will help maintain your strength or if it will only damage your muscles faster. The good news is that moderate exercise is generally safe and highly beneficial ^[1][2]. While exercise cannot cure or correct the underlying genetic causes of the disease ^[1], a carefully planned routine can help you improve your energy levels, manage fatigue, and preserve your mobility without accelerating muscle damage ^[1][2]. The key is finding the right balance—staying active to protect your joints and muscles, while avoiding excessive strain that could lead to overwork weakness.

Finding the Right Balance

For people living with myotonic dystrophy, physical therapy and tailored exercise guidelines are essential parts of standard care ^[3][4][5]. Working with a specialized multidisciplinary care team—which includes doctors, physical therapists, and occupational therapists—can help you stay active safely and adapt to changes in your physical abilities over time ^[6][7].

When starting out, a “moderate” routine might begin with just 5 to 10 minutes of light activity per day ^[1]. Since extreme fatigue is a common feature of this condition, learning to pace yourself and conserve energy is critical ^[1]. On days when your fatigue is overwhelming, it is perfectly acceptable to scale back your efforts or rest.

Recommended Types of Exercise

When designing an exercise routine, the goal is to maintain function and flexibility rather than building massive muscle or pushing yourself to exhaustion. Safe and effective activities generally include:

• Moderate, Low-Impact Aerobic Exercise: Activities like walking, swimming, or using a stationary bicycle can provide important physiological benefits over several months of consistent activity ^[2]. Studies show that aerobic training improves the function of mitochondria (the energy-producing centers within your cells) without worsening the disease ^[2][1].
• Light Resistance Training: Gentle, supervised resistance exercises over several weeks can help rescue some of the cellular energy dysfunction caused by the condition ^[8][9].
• Range-of-Motion Stretching: Daily stretching helps preserve joint flexibility, manage myotonia (the delayed relaxation of muscles after they contract), and reduce stiffness. Incorporating a thorough warm-up period is highly practical, as repeated gentle movements can temporarily reduce myotonic stiffness ^[3].
• Intermittent Gait Training: Structured walking exercises can be an effective way to maintain your independence and ability to perform daily tasks ^[10].

What to Avoid: The Risk of Overwork

While moderate activity is protective, pushing too hard can be harmful. It is important to avoid:

• High-Intensity Workouts: Pushing your body to exhaustion can cause excessive muscle fatigue and prolonged soreness ^[1].
• Eccentric Weightlifting: Exercises that focus on lengthening the muscle under tension (like the downward motion of a heavy bicep curl) can overwork vulnerable or severely weakened muscle fibers ^[1]. This is because it creates microscopic tears in the muscle fibers that dystrophic muscles cannot easily repair ^[2].
• Exercising Through Pain: If you experience severe muscle soreness that lasts more than 24 to 48 hours after an activity, you may be overworking your muscles ^[1]. Listen to your body and scale back your efforts.

Safety First: Heart Health, Lung Function, and Fall Prevention

Before beginning any exercise program, it is absolutely critical to undergo a thorough medical evaluation. Myotonic dystrophy frequently involves the heart, and issues like arrhythmias (irregular heartbeats) or conduction defects (problems with the electrical signals in the heart) are common and can be dangerous ^[11][12][13]. Your doctor may recommend an electrocardiogram (ECG) or echocardiogram to ensure your heart can safely handle physical exertion ^[12][14].

Additionally, because DM1 can also affect your breathing muscles, your care team should evaluate your pulmonary (lung) function before you begin aerobic activities like swimming, where breathing difficulties could pose significant risks ^[6][7].

Falls are another significant concern due to weakness in the lower legs and feet. Physical therapists can help you design strategies for fall prevention, which may include adapting your home environment, practicing balance exercises, or recommending assistive devices like ankle-foot orthoses (braces) or a cane ^[15]. Rehabilitation professionals will work with you to navigate these physical changes, helping to build confidence in your mobility and maintain your independence ^[5].