Muscle weakness can affect anyone — and often, it sneaks up over time.
What feels like ordinary fatigue might actually be a sign of something more serious.
Here are several possible reasons your muscles might be losing strength — and what you can do about it.
Aging’s quiet impact
As we age, it’s natural to lose muscle mass.
This process is called sarcopenia, and even though you might not notice it until your 60s or 70s, it’s one of the most common causes of muscle weakness.
Reduced physical activity and other health conditions can make it worse.
Medications might be the culprit
Many commonly used medications can weaken your muscles. Corticosteroids and statins, used to lower cholesterol, are prime examples.
If you’re feeling weaker and can’t figure out why, talk to your doctor or pharmacist — it might be a side effect.
Even a cold can knock you down
A bad cold or flu can leave your body feeling drained and your muscles weak for days.
In rare cases, viruses can even infect the muscles themselves — though that’s not common if you’re otherwise healthy.
COVID-19
COVID-19 doesn’t just affect the lungs. Being bedridden for days or weeks due to a serious case can rapidly reduce muscle strength.
The good news is with targeted physical activity and rehab, you can regain your strength over time.
Injury from overuse or strain
Lifting something too heavy or repeating the same motion too often can lead to muscle strain — or even a tear.
For mild cases, the R.I.C.E. method (Rest, Ice, Compression, Elevation) can speed up recovery. If it worsens, see a doctor.
When your immune system turns on you
Multiple sclerosis (MS) is a serious condition where the immune system attacks the protective covering of nerve fibers, disrupting communication between your brain and muscles.
This can cause muscle weakness in one or more limbs.
A stroke’s sudden signal
Sudden muscle weakness can be an early sign of a stroke.
It usually affects one side of the body and may be accompanied by dizziness, vision changes, speech problems, or confusion.
It’s a medical emergency — call 911 immediately.
Hidden health issues
Various other conditions — like thyroid disorders, sleep problems, chronic fatigue syndrome, heart failure, or diabetes — can all lead to muscle weakness.
If you feel like you’re losing strength and can’t explain it, consult a doctor.
Pregnancy
Fatigue is common during pregnancy, but muscle weakness isn’t — unless you have an underlying condition like myasthenia gravis.
If you’re pregnant and experiencing unexplained weakness, seek medical advice to rule out rare but serious issues like Guillain-Barré syndrome.
Your doctor is your best resource
If everyday activities suddenly become difficult due to weakness, it’s time to see your doctor.
They can examine you, ask questions, and run tests to identify the root cause — and distinguish between muscle issues and other problems like pain or balance.
This article is based on information from WebMD.