Heat exhaustion is a severe form of heat illness. It is a medical emergency. Heat exhaustion is caused by the loss of water and electrolytes through sweating. The United States Department of Labor makes the following recommendation, "Heat illness can be prevented. Remember these three things: water, rest, and shade." Causes
Common causes of heat exhaustion include:
Hot, sunny, humid weather
Physical exertion, especially in hot, humid weather
Due to impaired thermoregulation, elderly people and infants can get serious heat illness even at rest, if the weather outside is hot and humid, and they are not getting enough cool air. Some drugs, such as diuretics, antihistamines, beta-blockers, alcohol,  MDMA (Ecstasy, Molly), and other amphetamines can cause an increase in the risk of heat exhaustion.Especially during physical exertion, risk factors for heat exhaustion include:
Wearing dark, padded, or insulated clothing; hats; and/or helmets (for example, football pads, turnout gear, etc.) Having a higher percentage of body fat
Dehydration
Fever
Some medications, like beta blockers and antipsychotic medicines

Signs and symptoms
Symptoms of heat exhaustion include skin tingling, nausea, dizziness, irritability, headache, thirst, weakness, vomiting, high body temperature, excessive sweating, pupil dilation, and decreased urine output.
A chalazion (; plural chalazia or chalazions) or meibomian cyst is a cyst in the eyelid usually due to a blocked meibomian gland,  typically in the middle of the eyelid, red, and not painful. They tend to come on gradually over a few weeks.A chalazion may occur following a stye or from hardened oils blocking the gland. The blocked gland is usually the meibomian gland, but can also be the gland of Zeis.A stye and cellulitis may appear similar. A stye, however, is usually more sudden in onset, painful, and occurs at the edge of the eyelid. Cellulitis is also typically painful.Treatment is initiated with warm compresses. In addition, antibiotic/corticosteroid eyedrops or ointment may be used. If this is not effective, injecting corticosteroids into the lesion may be tried. If large, incision and drainage may be recommended. While relatively common, the frequency of the condition is unknown. It is most common in people 30–50 years of age, and equally common in males and females. The term is from the Greek khalazion (χαλάζιον) meaning "small hailstone".