Sudden sweating and shaking together usually mean your body’s “fight or flight” system has kicked into high gear. The most common cause is low blood sugar, which triggers these symptoms when levels drop below 70 mg/dL. But several other conditions, from anxiety and infections to hormonal shifts and medication effects, can produce the same combination. Understanding what’s behind it depends on the context: when it started, how long it lasts, and what else you’re feeling at the same time.
Low Blood Sugar Is the Most Common Cause
When your blood sugar drops too low, your brain sends an alarm signal through your nervous system. The result is a predictable cluster of symptoms: sweating, shaking, a racing heart, dizziness, and sudden hunger. This happens at blood sugar levels below about 70 mg/dL (or 4 mmol/L in countries that use that scale). It’s most familiar to people with diabetes, but it can happen to anyone who hasn’t eaten in a while, has exercised intensely, or has been drinking alcohol on an empty stomach.
If you suspect low blood sugar, the fix is straightforward: eat or drink something sugary right away. A small glass of fruit juice, a few glucose tablets, or a handful of jelly beans will work. Check how you feel after 10 to 15 minutes. If the shaking and sweating haven’t improved, have another sugary snack and reassess. Once you feel better, follow up with something more substantial like a sandwich or a proper meal to keep your blood sugar stable. If someone near you passes out from what you think is very low blood sugar, don’t try to give them food or drink. Place them on their side and call emergency services.
Anxiety and Panic Attacks
A sudden surge of adrenaline during a panic attack can look and feel almost identical to low blood sugar. Your hands shake, sweat breaks out across your forehead and palms, your heart pounds, and you may feel an overwhelming sense of dread. The episode typically peaks within 10 minutes and fades over 20 to 30 minutes, though it can feel much longer. If you’ve eaten recently and your blood sugar isn’t the issue, anxiety is one of the most likely explanations for a sudden episode of sweating and trembling.
Slow, deliberate breathing can help calm the nervous system during these episodes. Inhale for a count of four, hold briefly, and exhale for a count of six. This won’t stop a panic attack instantly, but it shortens the intensity and helps your body shift out of that heightened state faster.
Overactive Thyroid
If the sweating and shaking aren’t a one-time event but keep recurring over weeks, your thyroid could be producing too many hormones. An overactive thyroid speeds up your entire metabolism, causing trembling hands, excessive sweating, a rapid or pounding heartbeat, weight loss, nervousness, and trouble sleeping. People with this condition often feel uncomfortably warm, and their skin tends to feel warm and moist to the touch.
A doctor can check for this with a simple blood test. In rare cases, an overactive thyroid can escalate into a dangerous condition called a thyroid storm, which causes high fever, confusion, vomiting, and an irregular heartbeat. That’s a medical emergency, but it’s uncommon and usually triggered by a specific event like surgery or certain medications in someone whose thyroid problem is already severe.
Infection and Early Sepsis
When your body is fighting an infection, sweating paired with shivering or shaking (sometimes called rigors) is a classic response. Your internal thermostat resets to a higher temperature to help fight the infection, and the shaking is your muscles rapidly contracting to generate heat. You might also notice fast, shallow breathing, lightheadedness, or a change in mental clarity. These are early warning signs of sepsis, which is your body’s extreme and potentially dangerous response to an infection. If you have sweating, shaking, and confusion together, especially with a known infection or recent wound, that combination needs urgent medical attention.
Alcohol or Drug Withdrawal
If you’ve recently stopped or significantly reduced alcohol intake, sweating and tremors are among the earliest withdrawal symptoms. They can start within just a few hours of your last drink, typically peak around 72 hours, and reflect a rebound in nervous system activity. Along with the shaking and sweating, you might experience anxiety, headaches, stomach discomfort, and insomnia.
In more severe cases, alcohol withdrawal can progress to hallucinations (usually within 48 hours), seizures (between 8 and 48 hours after the last drink), or a dangerous state of confusion and cardiovascular instability that develops 3 to 5 days after stopping. Anyone with a history of heavy drinking who experiences escalating symptoms should not try to manage withdrawal alone. Withdrawal from certain other substances, including some sedatives and benzodiazepines, can produce similar symptoms.
Medication Side Effects
Several common medications can cause excessive sweating, and some also contribute to tremors. Antidepressants are frequent culprits, particularly SSRIs like fluoxetine and paroxetine, as well as SNRIs like venlafaxine. These drugs affect signaling in the parts of the brain that regulate temperature. Opioid pain medications, stimulant medications used for ADHD, older tricyclic antidepressants, and even thyroid replacement drugs can also trigger sweating. If your symptoms started or worsened around the time you began a new medication or changed your dose, that connection is worth discussing with your prescriber.
Hormonal Changes During Perimenopause
For women in their 40s and 50s, sudden sweating episodes are a hallmark of perimenopause. As estrogen levels fluctuate and eventually decline, the brain’s temperature control center becomes oversensitive. Small changes in body temperature that would normally go unnoticed instead trigger a cascade of flushing, sweating, and skin reddening. Many women also experience chills immediately afterward as the body overcorrects. While these episodes are typically called hot flashes, they can include a noticeable trembling or shaky feeling, especially if they happen at night and wake you from sleep.
Rare but Worth Knowing: Adrenal Tumors
A pheochromocytoma is a rare tumor of the adrenal glands that periodically dumps large amounts of stress hormones into the bloodstream. The classic symptoms are sudden, intense episodes of high blood pressure, pounding headache, heavy sweating, rapid heartbeat, and nervous shaking. Some people also experience pallor, shortness of breath, and a feeling of panic or doom. The key feature is that these episodes come and go in distinct “spells” or attacks, then resolve. This is uncommon, but if you’re having repeated, unexplained episodes that match this pattern, it’s something a doctor can test for.
Warning Signs That Need Immediate Attention
Most episodes of sudden sweating and shaking are uncomfortable but not dangerous. However, certain combinations of symptoms signal something more serious. Seek emergency care if your sweating and shaking come with chest pain or pressure, sudden confusion or difficulty thinking clearly, trouble breathing, loss of consciousness, very high or very low body temperature, or an inability to keep fluids down. These can indicate conditions like a heart attack, severe infection, dangerously low blood sugar, or a thyroid storm, all of which require rapid treatment.
If your episodes keep coming back and you can’t identify a pattern or trigger, keeping a simple log of when they happen, what you ate, what medications you took, and how long they lasted can give a doctor useful information. Blood sugar, thyroid function, and basic blood work can rule out or confirm most of the common causes in a single visit.