Some people diagnosed with multiple sclerosis (MS) feel like their arms are very heavy. Members of MyMSTeam often talk about feelings of weakness and heaviness in their arms. This may not be one of the first symptoms associated with MS, but heaviness in the arms is one of many possible MS symptoms.

Recognizing your symptoms and learning why they happen can help you talk with your healthcare team and find ways to feel better with MS.

What Do Heavy Arms With MS Feel Like?

Heavy arms can feel different for everyone with MS. For some, it is only a small problem. For others, it can make daily life much harder. Because this symptom can come and go, many members of MyMSTeam may wonder, “Why do my arms suddenly feel heavy and weak?”

“My arms are too heavy to hold the razor.”

— A MyMSTeam member

One MyMSTeam member said, “I always feel like I have Popeye arms. My forearms feel so heavy — like they’re pulling my arms right out of my shoulder sockets.”

This heaviness can make simple tasks hard. One member wrote, “Right now, my arms are heavy, and I’m struggling to type and use my hands.”

The feeling may happen in one arm or both. Some members say they feel this symptom so often that they try to do as much as possible on days when their arms feel strong. One member said, “If I wake up and can lift my arms and feel OK, it then becomes a ‘wash your hair’ day before I lose my arm strength.”

For some, arm weakness is constant or intense enough to affect all aspects of daily life. As one member shared, “I was a joiner for 30 years, but my arms got so weak, I had to pack it in. Now I’m 54, and I miss the work and the banter.”

What Causes Heavy Arms in MS?

Heavy arms in MS are usually caused by muscle weakness. Weak muscles are one of the most common signs of MS. Muscle weakness can happen for different reasons, such as lack of use, nerve damage, or fatigue. Sometimes, it can also show up during an MS flare-up.

Demyelination and Damaged Nerve Fibers

MS is an autoimmune disease. This means the immune system attacks the body by mistake. In MS, the immune system damages the myelin sheath — the protective cover around nerves in the central nervous system (the brain and spinal cord) — and the nerve fibers themselves. This damage is called demyelination, and it causes lesions (areas of damage) on the nerves. This damage affects the way the muscles work.

When nerves are damaged, muscles do not work the way they should. This can cause weakness (including in the arms), stiffness, spasms, pain, and lack of coordination. As a result of this demyelination, people with MS can also experience vision problems (like double vision or loss of vision), bladder problems, or bowel problems (including incontinence).

Deconditioning

Deconditioning happens when muscles are not used often. When muscles aren’t used regularly, they shrink (also called atrophy or muscle wasting) and become weaker. This is common for MyMSTeam members, who may find it harder to exercise and stay active because of fatigue, heat sensitivity, and mobility issues. Over time, this lack of use can lead to weaker arms that feel heavy.

Fatigue

Fatigue, or extreme tiredness, is one of the most common symptoms of MS. It affects about 80 percent of people with MS, according to the National Multiple Sclerosis Society. This fatigue may make muscle weakness worse. As one MyMSTeam member shared, “I also suffer from terrible bouts of fatigue. One minute, I am walking about my bungalow, then I collapse with no notice, absolutely shattered.”

Muscle Weakness as a Side Effect of Medication

Some people experience muscle spasms as a symptom of MS. Neurologists may treat this symptom by prescribing medications like baclofen (Lioresal) or tizanidine (Zanaflex). But for some people, medications meant to treat spasticity can increase muscle weakness. As one member shared, “I find it difficult to turn doorknobs or open jars, as my hand and arm strength has left me. I’m not sure if this is the MS or the high dose of baclofen I take to reduce spasticity.”

“I find it difficult to turn doorknobs or open jars, as my hand and arm strength has left me.”

— A MyMSTeam member

Weakness is also listed as a potential side effect for several disease-modifying therapies (DMTs) for MS, including:

• Interferons (like Avonex, Betaseron, Extavia, and Rebif)
• Peginterferon beta 1a (Plegridy)
• Siponimod (Mayzent)

Weakness caused by these medications is usually temporary, and it’s often linked to other side effects, such as flu-like symptoms.

Read about how DMTs are approved to treat MS.

Managing Heavy Arms With Multiple Sclerosis

You and your healthcare provider will need to work together to find the best way to treat your muscle weakness and heavy arms. Treatment for heavy arms usually starts with addressing the underlying MS, but there are also steps you can take to help with this specific symptom.

Try Physical and Occupational Therapy

A physical therapist can design an exercise plan to keep your arms strong. Physical therapy teams can also suggest exercises based on the specific cause of your arm weakness. Ask your neurologist for a referral to a physical therapist who has experience working with MS.

An occupational therapist can help you manage daily activities when arm heaviness gets in the way of your regular routine. They may teach you new ways to do everyday tasks so you can still get things done, even on days when your arms feel heavy.

Keep Exercising

If weak arms are caused by muscle loss (deconditioning) and atrophy, exercise can help. Physical activity can also improve your thinking skills, energy levels, and mood. Improvements in these areas can make MS easier to live with.

If you’re not able to work with a physical therapist, there are plenty of safe exercises you can do at home. The Multiple Sclerosis Society in the U.K. suggests simple exercises to help with balance and fatigue.

When muscle weakness in the arms is caused by demyelination and nerve damage, exercise is still important. But it should be done carefully to avoid overworking the damaged muscles and nerves.

“I often have ‘heavy arms’ and find that moderate exercise helps me feel stronger,” one MyMSTeam member said. “Water exercise is the best, because I don’t get overheated, the water provides ideal resistance, and I don’t have to fear falling down due to poor balance. I also go to a wellness center for seniors, where I can use weights, resistance bands, stationary bikes and ellipticals without fear of falling.”

Get Fatigue Under Control

If your fatigue seems linked to muscle weakness, talk to your neurologist about ways to manage it. Addressing fatigue may also help manage muscle weakness.

Some MyMSTeam members say their fatigue improved with prescribed medications. Keep in mind that medications can have side effects. Whenever possible, doctors prefer to first look at other causes of fatigue and suggest lifestyle changes.

For example, some members say that making changes to their diet or taking certain supplements has helped with MS fatigue. Always talk to your doctor before starting any new medication or supplements.

Find Your Team

On MyMSTeam, people share their experiences with MS, get advice, and find support from others who understand.

Is heaviness in your arms a common symptom and sign of MS? Do you notice that you feel heavy arms along with worsening cognitive problems, chronic pain, or other symptoms of multiple sclerosis? Let others know in the comments below.