First Aid Heat & Cold Exposure 5 Conditions Triggered by Excess Sun Exposure The Problem With Getting Too Much Sun By Rod Brouhard, EMT-P Updated on October 07, 2022 Medically reviewed by Michael Menna, DO Print Table of Contents View All Table of Contents Sunburn Dehydration Hyponatremia Heat Exhaustion Heatstroke Most people like to spend time outdoors on sunny days. Too much sun exposure, however, can have serious consequences. These can include: Sunburn Dehydration Hyponatremia, or water intoxication Heat exhaustion Heatstroke This article looks at some of the consequences of spending too much time in the sun. It also discusses some of the ways sun-related conditions can be treated. Science Photo Library / Getty Images Sunburn Sunburn is a common skin injury. It is caused by excess exposure to ultraviolet (UV) radiation from the sun. The injury happens when UV radiation directly damages the DNA in skin cells, triggering an inflammatory response. The damaged cells die and shed, which is what causes the peeling and flaking of skin. Sunburn Symptoms Common symptoms of sunburn include: Reddish skinPainSwellingFatigueHot skin temperatures Pain and redness tend to be greatest during the first six to 48 hours. DermNet / CC BY-NC-ND In severe cases, you may also have: RashNauseaFeverDizzinessChills If these symptoms occur, contact your doctor. Second-degree sunburns are more serious. Symptoms include: Blistering Oozing Dehydration Edema, or swelling of tissue Fainting When You're at Risk Sunburns don't only happen on hot summer days. You can get a sunburn even on a snowy or overcast day. You can reduce your risk by using sunscreen and sun-protective clothing. Remember that it only takes 15 minutes of direct sun exposure to cause a sunburn. Over time, excessive sun exposure can cause long-term problems, including: Skin damage Premature skin aging Skin cancer A history of severe sunburn gives you a 2.4-fold increase in your risk of squamous cell carcinoma and a 1.5-fold increase in the risk of melanoma. Treating Sunburn Mild sunburn can be treated at home with a cool bath or shower, cool compresses, and an over-the-counter moisturizing cream. For pain, you can take an over-the-counter pain reliever like Advil (ibuprofen) or Tylenol (acetaminophen). If blisters form, do not break them. How to Treat a Sunburn Dehydration Dehydration occurs when your body loses too many fluids or electrolytes. This can interfere with your normal body functions. On hot days, you may become dehydrated when you're not taking in as many fluids as you're losing. Symptoms of Dehydration Most healthy people can tolerate between a 3% to 4% loss of body water without symptoms. After 5%, you may develop: DizzinessHeadachesFatigue As the water loss exceeds 10%, severe symptoms can develop, including: Decreased urinationConfusionSeizures Treating Dehydration Mild dehydration will usually resolve when you drink water or an electrolyte-rich sports drink. The best way to avoid dehydration is to drink before you get thirsty. This is especially important if you plan to be in the sun for a long period or are overexerting yourself. How to Prevent Dehydration Recap Dehydration happens when your body loses more fluids and electrolytes than it takes in. You can avoid dehydration by drinking an electrolyte-rich sports drink before you start to feel thirsty. Hyponatremia The opposite of dehydration is hyponatremia. This is sometimes also called "water intoxication." Dehydration isn't just water loss. When you're dehydrated, your electrolytes also become imbalanced. Hyponatremia can occur when you lose a lot of water through sweat but you don't replace lost sodium when you rehydrate. Hyponatremia Symptoms Hyponatremia can happen when you lose too much fluid but only drink water. Unless you replace the lost sodium, you may experience the following symptoms: HeadacheFatigueLethargyLoss of appetiteIrritabilityMuscle weaknessCrampsConfusion Treating Hyponatremia Mild hyponatremia will usually resolve when you drink an electrolyte-rich sports drink. Severe cases need to be treated by emergency care providers. These cases are usually treated with a 3% saline solution delivered into a vein. Recap Drinking too much water when you're dehydrated can cause water intoxication. To avoid this, replace fluids with an electrolyte-rich sports drink. Heat Exhaustion Dehydration with prolonged sun or heat exposure can cause heat exhaustion. This happens when the body's core temperature rises above 98.6° but not above 104°. It typically occurs on hot, humid days when you're overexerting yourself. Risk of Heat Exhaustion Dehydration and obesity greatly increase the risk of heat exhaustion. Other factors that can contribute include: Alcohol use Caffeine use Use of certain drugs like diuretics, antihistamines, beta-blockers, alcohol, ecstasy, and amphetamines Babies and the elderly are at greatest risk. This is because their bodies aren't as good at adjusting to temperature changes. Heat Exhaustion Symptoms Common symptoms include: Dizziness Headache Nausea Thirst Weakness High body temperature Profuse sweating Decreased urination Vomiting Treating Heat Exhaustion If someone you know has heat exhaustion: Move them to a cool placeRemove any excess clothingBring down their body temperature by fanning or placing cool, wet towels on their skinOffer water or a sports drink if they can keep fluids downIf dizziness occurs, have them lie on their back and elevate their feet If symptoms don't improve after 15 minutes, call 911 or seek emergency medical care. Left untreated, heat exhaustion can lead to heatstroke. Heatstroke Heatstroke is also known as sunstroke. It is a more severe form of heat exhaustion. When you have heatstroke, your body's core temperature exceeds 104°. Heatstroke causes more than 600 deaths in the United States each year. There are two different types of heatstroke: Exertional heatstroke, caused by excessive exertion in hot temperaturesNon-exertional or "classic" heatstroke, caused by conditions that interfere with your body's ability to regulate its temperature Causes of Heatstroke Common risk factors for classic heatstroke include: Younger ageOlder ageAlcohol useStimulant useUse of certain medications Death from heatstroke often occurs when younger children or the elderly are left in parked cars in direct sunlight. On a hot day, temperatures inside a parked car can quickly climb to 124° to 153°. Heatstroke Symptoms Symptoms of heatstroke are more profound than heat exhaustion. They can differ based on whether you have exertional or classic heatstroke. For example, sweating is typical with exertional heatstroke but not with classic heatstroke. Other symptoms may include: Rapid breathingFast, weak pulseNausea and vomitingConfusion or deliriumHostilityIntoxication-like behaviorFainting and unconsciousnessSeizures, especially in children As symptoms advance, skin can suddenly take on a bluish tinge. This happens as blood vessels narrow and restrict blood flow and oxygen exchange. Left untreated, heatstroke can lead to: Organ failure Rhabdomyolysis, the breakdown of skeletal muscle Death Treating Heatstroke Heatstroke is an emergency. Treatment involves: Rapidly cooling the bodyOral and IV rehydrationStandard resuscitation measures by trained medical professionals Top Summer Health Risks to Avoid Recap Heat stroke is the most severe form of heat exhaustion. It can happen when you overexert yourself in hot weather or are exposed to extremely hot conditions. If you suspect heatstroke, seek medical care at once. Summary Too much time in the hot sun can lead to a number of health conditions. This includes sunburn, dehydration, hyponatremia, heat exhaustion, and heatstroke. You can avoid these conditions by taking the right precautions. Use sunscreen and sun-protective clothing. Replace lost fluids and electrolytes with a sports drink. Learn to recognize the symptoms of heat exhaustion and heat stroke and avoid exerting yourself in hot, humid weather. 14 Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. D'Orazio J, Jarrett S, Amaro-Ortiz A, Scott T. UV radiation and the skin. Int J Mol Sci. 2013;14(6):12222-48. doi:10.3390/ijms140612222 MedlinePlus. Sunburn. Nemours KidsHealth. First aid: sunburn (for parents). Wu S, Cho E, Li WQ, Weinstock MA, Han J, Qureshi AA. History of severe sunburn and risk of skin cancer among women and men in 2 prospective cohort studies. Am J Epidemiol. 2016;183(9):824-33. doi:10.1093/aje/kwv282 American Academy of Dermatology. How to treat sunburn. Cleveland Clinic. Hyponatremia. Lee JJ, Kilonzo K, Nistico A, Yeates K. Management of hyponatremia. CMAJ. 2014;186(8):E281-6. doi:10.1503/cmaj.120887 Casa DJ, Demartini JK, Bergeron MF, et al. National Athletic Trainers' Association position statement: exertional heat illnesses. J Athl Train. 2015;50(9):986-1000. doi:10.4085/1062-6050-50.9.07 National Collaborating Centre for Environmental Health. Drugs. Centers for Disease Control and Prevention. Warning signs and symptoms of heat-related illness. Centers for Disease Control and Prevention. Heat-related illness. Ferrara P, Vena F, Caporale O, et al. Children left unattended in parked vehicles: a focus on recent Italian cases and a review of literature. Ital J Pediatr. 2013;39:71. doi:10.1186/1824-7288-39-71 Hifumi T, Kondo Y, Shimizu K, Miyake Y. Heat stroke. J Intensive Care. 2018;6:30. doi:10.1186/s40560-018-0298-4 People’s Liberation Army Professional Committee of Critical Care Medicine. Expert consensus on standardized diagnosis and treatment for heat stroke. Mil Med Res. 2016;3:1. doi:10.1186/s40779-015-0056-z By Rod Brouhard, EMT-P Rod Brouhard is an emergency medical technician paramedic (EMT-P), journalist, educator, and advocate for emergency medical service providers and patients. See Our Editorial Process Meet Our Medical Expert Board Share Feedback Was this page helpful? Thanks for your feedback! What is your feedback? Other Helpful Report an Error Submit