(flickr, Schjelerup) 

A humid summer day can do more than leave you needing a shower--it can actually cause serious health problems.  Here’s a rundown of some of the ways extreme heat can do your body damage and how you can protect yourself. 

Heat rash

Heat rash occurs when sweat ducts and hair follicles on the skin become blocked and irritated.  This happens because human sweat has a high salt content, which can become a very potent skin irritant, especially in humid conditions.  The symptoms can range from minor blisters to deep, red lumps, plus itching or a prickly feeling.

Heat rash usually clears up on its own after a few days, but some cases may need medical care.  The best way to prevent it is to keep your skin cool and dry, and to wash off sweat with gentle soap and water

Hyperthermia

Hyperthermia, the underlying cause of most heat illnesses, happens when the body absorbs more heat than it can dissipate.  Usually, the body keeps itself cool by what’s known as thermoregulation, better known as simple sweating. But when the body’s temperature regulators cannot keep up with the external temperature, you overheat.

The severity of hyperthermia depends on several factors, including the outdoor temperature, the health of the individual and the humidity.  For example a young, fit person will fare better on a 90-degree day in dry heat than an elderly person dealing with high humidity and high temperatures.

Hyperthermia can lead to three heat-related illnesses: heat cramps, heat exhaustion and heat stroke.  They are usually progressive so it’s important to be able to recognize the early symptoms of the milder heat illnesses, such as heat cramps, so you can avoid a more severe condition like heat stroke.

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Heat cramps

Heat cramps are involuntary muscle spasms that occur during physical exertion in hot temperatures.  They usually are caused by dehydration and can feel similar to nighttime leg cramps, but last longer and can be more intense.

If you suspect you have heat cramps, stop whatever you are doing. Drink plenty of fluids--preferably fluids that also have electrolytes, such as sports drinks.  Gently massage or stretch the muscles that are cramping and do not resume activity for several hours after the cramps subside.

Heat Exhaustion

Heat exhaustion is a condition that often follows heat cramps and precedes heat stroke.  It is caused by exposure to high temperatures – usually when combined with high humidity – and strenuous physical activity. 

Its symptoms can come on suddenly or over time depending on the individual, and can include:

• Cool, moist skin with goose bumps
• Heavy sweating
• Faintness
• Weak, rapid pulse
• Low blood pressure
• Muscle cramps (heat cramps)
• Nausea
• Headache

When these symptoms begin to present themselves, it’s important to respond immediately. Heat exhaustion is much easier to treat than heat stroke and usually does not result in permanent damage.