Some people diagnosed with multiple sclerosis (MS) feel like their arms get very heavy. Members of MyMSTeam regularly describe feelings of weakness and heaviness in their arms. While it may not be one of the first symptoms associated with MS, heaviness in the arms is one of many possible MS symptoms.

Recognizing your MS symptoms and learning why they happen can help you have better conversations with your health care team and find solutions to improve your quality of life with MS.

What Do Heavy Arms With MS Feel Like?

Heavy arms with MS can take many forms. They can be a minor inconvenience, or they can significantly affect your daily life. Since this symptom can come and go unexpectedly, members of MyMSTeam may wonder, “Why do my arms suddenly feel heavy and weak?” As one MyMSTeam member said, “My arms and legs feel really heavy today and very weak.”

Heaviness in the arms can make it harder to get through the day. As one member wrote, “Right now, my arms are heavy, and I’m struggling to type and use my hands.” Another commented, “My arms are too heavy to hold the razor.”

The heaviness may occur in only one arm or in both. Some members find that heavy arms occur so frequently that on their “good” days, they try to get as much done as possible. As one member wrote, “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.”

Arm weakness can be persistent or severe enough to impact all aspects of 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 am 54, and I miss the work and the banter.”

What Causes Heavy Arms in MS?

Heavy arms associated with MS are usually a result of muscle weakness — one of the condition’s most common signs. Muscle weakness can have various causes, including lack of use, nerve damage, or fatigue. It could even be a new symptom due to a flare-up.

Demyelination and Damaged Nerve Fibers

MS is an autoimmune disease that causes damage to the myelin sheath — the protective coating around nerves in the central nervous system (the spinal cord and brain) — and the nerve fibers themselves. This damage is referred to as demyelination. It causes lesions (areas of damage) to form on the nerves.

In people with MS, the immune system’s attacks on the central nervous system affect the way the muscles work. These attacks 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 blurry vision or loss of vision), bladder problems, or bowel problems (including incontinence).

Deconditioning

Deconditioning occurs when people stop using their muscles. When muscles are not used regularly, they become smaller (also called atrophy or muscle wasting) and weaker. This is a common struggle for MyMSTeam members, as many find it harder to exercise and stay active due to fatigue, heat sensitivity, and mobility problems. Over time, this can lead to weak arms that feel heavy.

Fatigue

Fatigue, or extreme tiredness, is one of the most common MS symptoms. It affects roughly 80 percent of people with MS, according to the National Multiple Sclerosis Society. This fatigue may contribute to muscle weakness. As one MyMSTeam member described, “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 others, the increased muscle weakness is caused by medications meant to treat spasticity. 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.”

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

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

Weakness associated with these medications is usually temporary, and it is often linked with other side effects, including flu-like symptoms.

Managing Heavy Arms With Multiple Sclerosis

You and your health care provider will need to work together to determine how to treat your muscle weakness and heavy arms. Managing heavy arms associated with MS usually begins with treating the underlying MS, but there are several additional ways you can address weakness and heavy arms specifically.

Try Physical and Occupational Therapy

Physical therapists can come up with an exercise plan to keep your arms healthy and strong. They can also help you with exercises tailored to the cause of your arm weakness. Ask your neurologist for a referral to a physical therapist who has worked with people diagnosed with MS and understands the condition.

Occupational therapists can help you find ways to complete daily tasks if arm heaviness is getting in the way of your regular routine. They may show you how to perform daily tasks in different ways so you can still get them done even when your arms feel heavy.

Keep Exercising

If deconditioning and muscle atrophy have caused your muscles to grow weaker, exercise can be helpful. It can also help prevent the development of comorbidities (related health conditions) that are more common in people with MS, such as high blood pressure.

Not everyone has the means or the opportunity to work with a physical therapist, but there are plenty of safe exercises people with MS can do at home. The UK-based Multiple Sclerosis Society suggests simple exercises to manage balance and fatigue. When muscle weakness in the arms is caused by demyelination and nerve damage, exercise is still important, but it must be modified to avoid causing fatigue in damaged nerves.

Get Fatigue Under Control

If your fatigue seems related to muscle weakness, talk to your neurologist about how to manage it. Addressing fatigue may be helpful in managing muscle weakness.

Some MyMSTeam members report improving their fatigue with prescribed medications, including:

• Amantadine
• Modafinil (Provigil)
• Amphetamine/dextroamphetamine (Adderall)
• Methylphenidate (Concerta, Ritalin LA)

It is important to remember medications do come with side effects and, when possible, addressing other causes of fatigue and making lifestyle changes are the preferred options. For example, other members mention that making changes in what they ate or taking certain supplements have helped them with their MS fatigue. Always talk to your doctor before beginning any new medications or supplements.

Find Your Team

MyMSTeam is the social network for people diagnosed with MS and their loved ones. On MyMSTeam more than 216,000 members come together to ask questions, give advice, and share their stories with others who understand life with MS.

What common symptoms and signs of MS affect your daily life the most? Do you notice that heavy arms occur along with worsening cognitive problems, chronic pain, or other symptoms of multiple sclerosis? Share your tips in the comments below or by posting on MyMSTeam.