Why do my legs ache at night when I have not done anything?

Common reasons include low potassium or calcium, a diuretic or other medicine, and simple muscle tension. If it happens most nights, ask for a blood panel that includes electrolytes, vitamin D, and thyroid function.

Should I stop my statin if my muscles hurt?

No, not without talking to your prescriber. The American Heart Association found that in trials, statin and placebo groups reported muscle symptoms at rates less than 1% apart. Your doctor can check CK and try a lower dose or a different statin. Call right away if you have weakness or dark urine.

Can dehydration cause body aches?

Dehydration can contribute, mainly by shifting electrolytes and, in severe cases, by adding to the risk of muscle breakdown. It is rarely the only cause of aches that last more than a day or two. Look for another explanation if drinking fluids does not help.

What blood tests check for unexplained muscle aches?

Doctors often start with a TSH for thyroid function, a CK for muscle damage, electrolytes including potassium and calcium, and vitamin D. Inflammation markers help if polymyalgia rheumatica is possible. A complete blood count and kidney function round out a basic workup.

Is it normal to ache all over before I get sick?

Yes. Body aches often start before or with a fever in viral illnesses such as the flu, and the CDC notes flu symptoms usually come on suddenly. The aches normally ease as the fever goes. Aches that outlast the illness by more than a week deserve a check.

Why Do My Muscles Ache When I Have Not Exercised?

The short answer: Muscle aches without exercise usually come from a viral infection, a medicine such as a statin, or stress and poor sleep. Less common but treatable causes include an underactive thyroid, low vitamin D, low potassium, polymyalgia rheumatica, and fibromyalgia. Most aches fade within a few days. Dark, cola-colored urine, true muscle weakness, or a high fever with a stiff neck need care the same day.

The MedlinePlus page on muscle aches lists overuse and injury first. When you have not exercised, the rest of its list becomes more useful: tension and stress, infections such as the flu and Lyme disease, electrolyte imbalances, fibromyalgia, lupus, and medicines including statins and ACE inhibitors.

Think about the pattern before you think about the cause. Four questions sort most cases:

Did it start suddenly, with fever or chills? That points toward an infection.
Did it start after a new medicine or a dose change? That points toward a side effect.
Is it worst in the shoulders and hips on waking, and are you over 50? That points toward polymyalgia rheumatica.
Has it been widespread for months, with poor sleep and fatigue? That points toward fibromyalgia, a thyroid problem, or depression.

Write down where it hurts, when it started, and what else changed. That record shortens the workup.

Could it be a virus or an infection?

This is the most common reason for sudden, all-over aching. The CDC lists muscle or body aches among flu symptoms that usually come on suddenly, along with fever, chills, cough, sore throat, headache, and fatigue. COVID-19 and many other viral illnesses cause the same pattern.

Viral aches usually ease as the fever breaks. Rest, fluids, and an over-the-counter pain reliever are the standard home care that MedlinePlus describes.

The CDC also lists emergency warning signs for adults with the flu. Two of them are about muscles: severe muscle pain and severe weakness or unsteadiness. Not urinating, difficulty breathing, and confusion are also on the list. MedlinePlus adds tick bites and a new rash as reasons to see a doctor, because Lyme disease can cause aches without the usual cold symptoms.

Can medicines like statins cause muscle pain?

Yes, though less often than people think. Statins are the drug most people suspect. The American Heart Association's 2019 scientific statement on statin safety reports that about 10% of patients in US practice stop a statin because of subjective complaints, most often muscle symptoms without a raised creatine kinase (CK, a marker of muscle damage).

The same statement found a different picture in randomized trials. The difference in muscle symptoms between statin and placebo groups was under 1%. The authors concluded that these symptoms are usually not caused by the drug itself. The risk of serious statin muscle injury, including rhabdomyolysis, is under 0.1%.

That does not mean you should ignore new aches. The MedlinePlus atorvastatin page tells patients to call a doctor right away for muscle pain, tenderness, or weakness, extreme tiredness, fever, or dark-colored urine. Do not stop a statin on your own. A doctor can check your CK and adjust the dose or the drug.

Other medicines matter too. MedlinePlus names ACE inhibitors, used for blood pressure. Diuretics can drop your potassium, which is covered below.

Could my thyroid, vitamin D, or electrolytes be the cause?

These are the causes a basic blood panel can find.

Underactive thyroid. The NIDDK lists joint and muscle pain among hypothyroidism symptoms, with fatigue, weight gain, trouble tolerating cold, dry skin, and depression. A blood test confirms it. thyroid.md covers thyroid-related muscle problems in more depth. If you also feel cold all the time, see why am I always cold.
Low vitamin D. Long-term vitamin D deficiency can cause osteomalacia, a softening of the bones. MedlinePlus lists widespread bone pain, especially in the hips, and muscle weakness among its symptoms. Low calcium can add cramps, spasms, or tingling. The diagnosis uses blood tests for vitamin D, calcium, phosphate, and parathyroid hormone.
Low potassium. The MedlinePlus hypokalemia page lists muscle weakness or spasms, tingling, and muscle damage. Common causes are diuretics, some antibiotics, and diarrhea or vomiting. Severe drops can disturb the heart rhythm.

What if I am over 50 and stiff every morning?

Consider polymyalgia rheumatica. The NIAMS says it occurs almost only in people older than 50, typically in their late 60s and 70s. Women get it more often than men.

The typical complaint is pain and stiffness in the shoulders, neck, upper arms, and hips. It is worse on waking or after rest and usually lasts an hour or more. Some people cannot raise their arms or get out of bed easily. It responds well to treatment, so it is worth naming to your doctor.

Polymyalgia has a dangerous relative. NIAMS states that about 10 percent of people with polymyalgia rheumatica have giant cell arteritis. New temple headaches, jaw pain when chewing, scalp tenderness, or any change in vision need a doctor right away. NIAMS warns that untreated vision symptoms can lead to permanent vision loss within hours or days.

Can stress, poor sleep, or depression make my muscles ache?

Yes, and this group is easy to overlook. The NIMH lists physical aches or pains, headaches, and cramps without a clear physical cause among depression symptoms. It also lists sleep problems and fatigue. depression.md covers screening and treatment.

Fibromyalgia sits in the same space. The NIAMS describes chronic, widespread pain with fatigue, sleep trouble, stiffness, and problems with concentration. More women get it than men. Research shows people with fibromyalgia have increased sensitivity to pain. There is no cure, but exercise, therapy, and medicines help manage it. Constant tiredness has its own list of causes, which our fatigue causes guide covers.

Fibromyalgia and depression are diagnoses a doctor reaches after ruling out the blood-test causes above. Ask for that workup first.

When are muscle aches an emergency?

Watch for rhabdomyolysis, the breakdown of muscle tissue. MedlinePlus names dark, red, or cola-colored urine as its tell-tale sign. Other signs are weakness, tenderness, stiffness, and passing less urine. Causes include drugs such as cocaine and amphetamines, extreme heat, dehydration, and genetic muscle disease. It can lead to kidney failure.

Also know the difference between pain and weakness. Aching muscles still work. Weak muscles cannot lift, climb, or grip the way they did. New weakness needs prompt evaluation.

MedlinePlus says to call 911 for muscle aches with any of these:

Trouble breathing or swallowing
Muscle weakness, or not being able to move a part of the body
Vomiting, a very stiff neck, or a high fever
Sudden weight gain or water retention

See a doctor within days if the pain lasts more than 3 days, is severe and unexplained, or comes with a rash or tick bite. Our list of red flag symptoms covers other signs that should not wait.

The bottom line

Aches without exercise are usually a virus, stress, poor sleep, or a medicine side effect, and most settle within days. Aches that last weeks deserve a simple blood panel for thyroid, vitamin D, electrolytes, and CK. Morning stiffness in the shoulders and hips after 50 points to polymyalgia rheumatica. Dark urine, real weakness, or vision changes need care the same day.

Last updated: September 2026. This article is for informational purposes only and does not constitute medical advice. Talk to a clinician about muscle aches that last more than a few days, and do not stop a prescribed medicine without medical advice.