Several medical conditions can make a person feel weak, shaky, and tired. They include dehydration, irregular heart beat, Parkinson’s disease, and chronic fatigue syndrome.

Treatment will depend on the condition a person has.

Keep reading to learn about the conditions associated with these symptoms, as well as some home remedies that may help.

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A person bent over, hands on knees, feeling shaky, weak, and tired. Credit: Hinterhaus Productions/Getty Images

The following factors can cause a sudden onset of weakness, shakiness, or tiredness:

  • Hypoglycemia: In this condition, blood sugar drops below 70 milligrams (mg) per deciliter. It often occurs when a person with diabetes takes more insulin or medication than they need to lower their blood sugar.
  • Low blood pressure: This occurs when a person has a blood pressure lower than 90/60 millimeters of mercury. When this happens, the force of the blood pushing against the walls of the arteries is too low. Causes include bleeding, heart problems, pregnancy, and aging.
  • Too much caffeine: Healthy adults can usually safely consume 400 mg of caffeine per day, but higher doses can be harmful. However, some people are more sensitive to caffeine, so they may experience negative effects — such as shakiness, weakness, and tiredness — at lower doses.
  • Dehydration: This occurs when a person loses more fluids than they take in. Causes include nausea, vomiting, fever, loss of appetite, and profuse sweating.
  • Medications: Some drugs may produce these symptoms.

Several medical conditions can involve feeling weak, shaky, and tired. The following sections will look at some of these in more detail.

Irregular heart rhythm

Doctors call an irregular heart rhythm an arrhythmia. This means that the heart beats too fast, too slowly, or erratically.

When the heart rate is abnormal, the heart cannot pump blood effectively, which can cause weakness and tiredness.

Arrhythmias can be harmless or life threatening, according to the American Heart Association (AHA).


Tremors involve rhythmic, involuntary muscle contractions that lead to shaking in one or more parts of the body.

Although they affect the hands most frequently, they may also affect the legs, arms, torso, or head, according to the National Institute of Neurological Disorders and Stroke.

Tremors may occur at any age, but they tend to affect middle-aged and older adults more often.

Chronic fatigue syndrome

Chronic fatigue syndrome is a serious, long-term condition that involves many systems of the body.

Symptoms include severe tiredness, sleep problems, and difficulty thinking.

According to the Centers for Disease Control and Prevention (CDC), people with this condition often cannot perform their everyday activities.

Parkinson’s disease

Parkinson’s disease is a brain condition that causes shaking, stiffness, and balance problems. It usually starts gradually and worsens over time, according to the National Institute on Aging (NIA).

As it progresses, individuals may experience tiredness, memory loss, and depression. The NIA says that the condition affects 50% more men than women.

Feeling weak, shaky, and tired may be due to a number of conditions or other factors.

Some causes may be easy to treat. For example, since too much caffeine can sometimes cause these effects, a person may wish to reduce their intake of caffeinated beverages to see if it helps reduce the symptoms.

Dehydration is another condition that a person can treat easily.

The AHA explains that the easiest way for a person to know if they are getting enough fluids is to look at their urine. If it is pale and clear, they are probably not dehydrated.

On the other hand, if the urine is dark, it may be a sign that they need to increase their fluid intake. The AHA notes that water is the most healthy beverage for rehydrating.

Another way to reduce tiredness and weakness is to eat a nutritious diet. This increases energy, improves general health, and reduces the risk of developing serious medical conditions, according to the National Institute of Diabetes and Digestive and Kidney Diseases.

Here are a few tips from the CDC on how to eat a nutritious diet:

  • Focus on fruits, vegetables, whole grains, and low fat dairy products.
  • Include high protein foods, such as fish, poultry, lean meat, beans, nuts, and eggs.
  • Avoid or limit foods that are high in saturated fat, trans fat, salt, and sugar.
  • Aim for a daily calorie intake that falls within the recommendations.

If a person has difficulty eating enough, they may benefit from eating small, frequent meals rather than three larger meals per day. When snacking, try choosing a nutritious food, such as fruit, instead of chips or candy.

Physical activity also offers excellent health benefits and can help a person feel stronger. People should try to get 150 minutes of moderate-intensity exercise per week, according to the AHA. However, individuals should always check with their doctor before starting any exercise program.

If the symptoms persist or worsen, even after a person makes some lifestyle modifications to improve their general health, they should contact a doctor.

Several medical conditions may cause these symptoms, so getting medical attention can help a person get a specific diagnosis.

To receive a diagnosis, a person may need to undergo blood tests and other laboratory tests or procedures. Afterward, a doctor may prescribe medications or other treatment types that are appropriate for the person’s condition.

For instance, if someone’s symptoms are due to hypoglycemia associated with diabetes, a doctor can adjust their dosage of insulin or other drugs. Likewise, if an individual’s symptoms stem from tremors, taking antiseizure medications may reduce them.

The best way to determine the cause is to contact a doctor.

The following are answers to commonly asked questions about feeling shaky and tired.

What should I eat if I feel weak and shaky?

If a person feels weak and shaky because of low blood sugar, they can try eating a carb-rich snack. Drinking fluids and electrolytes can help if they are dehydrated.

Why do I feel shaky and jittery inside?

There are a range of possible causes. Some common ones include low blood sugar, low blood pressure, too much caffeine, and dehydration.

Feeling weak, shaky, and tired may be due to something that is easy to treat.

For example, if the symptoms stem from dehydration, drinking more water should resolve the problem. Likewise, some chronic conditions that cause these symptoms might improve when a person engages in healthy lifestyle habits.

However, some other conditions, such as tremors, may need medical treatment.

If a person experiences ongoing symptoms, they should consider talking with a doctor.