Why am I shaking after being in the sun? Understanding the causes

September 21, 2025 •

4 min read

Millions of people enjoy time in the sun, yet a surprising number experience a strange reaction afterward. Feeling shaky or having chills after sun exposure is not uncommon and often points to your body's attempt to regulate its internal temperature. Understanding why this happens is crucial for your health and safety.

Quick Summary

Shaking after sun exposure is typically a sign of your body's disrupted temperature regulation, caused by issues like dehydration, heat exhaustion, or a severe sunburn. It is your body's natural response to heat stress and is often a clear signal to rest, rehydrate, and cool down immediately.

Key Points

Disrupted Thermoregulation: Shaking after sun exposure is often a sign of your body's cooling system failing, causing a compensatory shivering response.
Dehydration Is a Major Factor: Excessive sweating and inadequate fluid intake lead to dehydration, which impairs your body's ability to maintain a stable temperature, triggering chills and shaking.
Heat Exhaustion is a Serious Cause: Shaking is a classic symptom of heat exhaustion, a severe condition resulting from prolonged heat exposure that requires immediate rest, rehydration, and cooling.
Severe Sunburn Can Trigger Systemic Response: 'Sun poisoning,' or a severe sunburn, can cause a full-body inflammatory response, leading to flu-like symptoms including fever, headache, and shaking chills.
Prevention is Key: Staying hydrated, seeking shade, and using sunscreen are the most effective strategies to prevent the body from reaching a state of heat stress.
Know When to Seek Help: If shaking persists or is accompanied by confusion, high fever, or loss of consciousness, seek immediate medical attention as it could indicate heatstroke.

Your Body's Response to Heat Stress

When your body is exposed to direct sunlight for an extended period, it must work harder to maintain a stable internal temperature, a process known as thermoregulation. The shaking you feel, often accompanied by chills, is a primitive reflex to generate heat when your body's core temperature has dropped. Ironically, this happens even after overheating due to issues like severe dehydration or heat exhaustion.

Dehydration's Role in Post-Sun Shaking

Spending time in the heat and sun causes your body to sweat to cool down. If you don't adequately replace the fluids lost through sweating, you become dehydrated. Dehydration impacts your blood volume and electrolyte balance, which in turn impairs your body's ability to regulate temperature effectively. This can lead to a phenomenon where your body overcompensates, causing chills and shaking as it attempts to correct its core temperature. This can happen even when the air around you is still hot.

The Dangers of Heat Exhaustion

Heat exhaustion is a direct consequence of prolonged sun exposure and dehydration. It is a serious condition that requires immediate attention. Shaking, shivering, or chills are common symptoms. This is your body's attempt to cool down, but it is an alarm bell indicating that your body's internal cooling system is in distress. Other signs include excessive sweating, a rapid pulse, headache, dizziness, and nausea. If left untreated, heat exhaustion can escalate to a life-threatening heatstroke.

The Link Between Severe Sunburn and Sun Poisoning

Another significant cause of post-sun shaking is a severe sunburn, sometimes referred to as 'sun poisoning.' This is not actual poisoning but an inflammatory reaction to extreme UV damage to your skin. The widespread skin damage can trigger a systemic response, causing your body's immune system to kick into high gear. This can result in flu-like symptoms, including fever, headache, fatigue, and intense chills or shaking. Blistering and pain are also common indicators of sun poisoning.

Immediate Actions for Relief

If you begin to shake or feel chills after being in the sun, it's essential to act quickly. Your body is telling you that something is wrong. Follow these steps immediately:

Move to a cool environment. Get out of the sun and into a shady or air-conditioned area immediately. This is the most crucial first step to stop your body from overheating further.
Rehydrate with cool fluids. Drink water or a sports drink with electrolytes. Avoid alcohol or caffeinated beverages, as they can worsen dehydration.
Cool your body down. Take a cool shower or apply cool, damp compresses to your neck, wrists, and forehead. A cool bath can also help.
Rest and elevate your feet. Lie down and prop your legs up slightly to improve blood circulation and reduce strain on your cardiovascular system.
Loosen tight clothing. Wear loose, lightweight clothing to allow for better air circulation and cooling.

Comparison of Sun-Related Illnesses


Symptom	Dehydration	Heat Exhaustion	Sun Poisoning (Severe Sunburn)
Shaking/Chills	Possible, due to temperature dysregulation.	Common and often severe.	Common, accompanied by fever.
Sweating	Decreased or heavy sweating.	Heavy, profuse sweating.	Skin may be hot and dry, but chills are a systemic response.
Dizziness	Common.	Common, often with fainting.	Possible, due to inflammation.
Nausea/Vomiting	Possible.	Common.	Common.
Skin Appearance	Pale or flushed.	Pale, cool, and clammy.	Red, painful, and possibly blistering.
Fever	Possible, but usually low-grade.	Up to 104°F (40°C).	Possible, often with shaking chills.

Prevention is Your Best Defense

Taking preventative measures is far easier than treating the symptoms of sun-related illness. By following a few simple rules, you can significantly reduce your risk of shaking and other complications:

Drink plenty of fluids throughout the day, especially when outdoors.
Limit your time in direct sunlight, particularly during peak hours between 10 a.m. and 4 p.m.
Wear a wide-brimmed hat, sunglasses, and loose-fitting, light-colored clothing.
Use broad-spectrum sunscreen with an SPF of 30 or higher and reapply every two hours, or more frequently if sweating or swimming.
Take regular breaks in the shade to allow your body to cool down.

When to Seek Medical Attention

While mild shaking after sun exposure can often be managed with at-home care, certain symptoms warrant a doctor's visit or emergency care. You should seek immediate medical help if you experience:

Confusion, slurred speech, or loss of consciousness.
A body temperature of 103°F (39.4°C) or higher.
A rapid, weak pulse.
Severe, non-stop vomiting.
Seizures.

For more detailed information on heat-related illnesses and treatment, refer to authoritative sources such as the Centers for Disease Control and Prevention guidelines here.

Conclusion

Shaking after being in the sun is a clear signal that your body is under stress. Whether caused by dehydration, heat exhaustion, or a severe sunburn, it's a symptom that should never be ignored. By understanding the underlying causes and taking immediate steps to cool down and rehydrate, you can prevent more severe complications and ensure your health and safety. Always prioritize sun safety and listen to your body's signals to enjoy the warmer months safely.

Frequently Asked Questions

You get chills because your body's thermoregulation is disrupted. After overheating, your body might overcompensate and attempt to cool down by constricting blood vessels and shivering, which is meant to generate heat, leading to a sensation of being cold.

Yes, dehydration is a very common cause. When you become dehydrated from sweating, your blood volume and electrolyte balance are affected. This impairs your body's ability to regulate its temperature, often resulting in chills and shaking.

Sun poisoning is a term for a severe sunburn that causes a systemic inflammatory response. It can certainly cause shaking, chills, fever, and other flu-like symptoms as your body reacts to extensive skin damage from UV rays.

While shaking is more common with heat exhaustion, it can be a precursor to heatstroke. If shaking is accompanied by a very high body temperature (over 103°F), confusion, or unconsciousness, it is a medical emergency and you should seek immediate help.

The first step is to get out of the sun and into a cool, shaded area. Then, lie down and rehydrate with cool fluids like water or a sports drink. Applying a cool, damp cloth to your skin can also help lower your body temperature.

Yes, in many cases, moving to a cool place and using cooling measures (like a cool shower or compresses) can help your body regain control of its temperature and stop the shaking. This is especially effective if the cause is mild dehydration or heat exhaustion.

Preventative measures include staying well-hydrated throughout the day, limiting sun exposure during peak hours, wearing protective clothing and sunscreen, and taking frequent breaks in the shade.