Heat Injury Prevention for the Horseman

Last week's post focused on heat injury for horses, so I thought this week would be a good time to remind us of the dangers and precautions to take for ourselves, too! As hot as it has been lately and will continue for the next month or two, it’s never too late to review ways to protect yourself from heat exhaustion and heat stroke.  Most certainly, horse owners, trainers, and anyone riding are out in the heat and humidity enough to experience risky conditions.  To help with this, the following information has been supplied by the US Department of Labor Occupational Safety and Health Administration (OSHA):

When the body is unable to cool itself through sweating, serious heat illnesses may occur.  The most severe heat induced illnesses are heat exhaustion and heat stroke. If left untreated, heat exhaustion could progress into heat stroke and possible death.  When temperatures exceed 85 degrees and 30% humidity we should be cautious, but once they exceed 95 degrees and 60% humidity, the danger escalates.

Symptoms of heat exhaustion include headaches, dizziness or lightheadedness, weakness, mood changes such as irritability, confusion or the inability to think straight, upset stomach, vomiting, decreased or dark colored urine, fainting or passing out, and pale, clammy skin.  To minimize and prevent heat exhaustion, the following steps should be taken:

1. Act immediately.  If not treated, heat exhaustion may advance to heat stroke or death.
2. Move the victim to a cool, shaded area to rest.  Don’t leave the person alone.  If symptoms include nausea or upset stomach, lay the victim on his or her side.
3. Loosen and remove any heavy clothing.
4. Have the person drink cool water (about a cup every fifteen minutes) unless sick to the stomach.
5. Cool the person’s body by fanning and spraying with a cool mist of water or applying a wet cloth to the person’s skin. 
6. Call 911 for emergency help if the person does not feel better in a few minutes.

Heat Stroke includes the same symptoms as heat exhaustion, but may also include dry, pale skin with no sweating, hot red skin that looks sunburned, seizures or fits, and unconsciousness with no response.

In addition to the above steps for heat exhaustion, during heat stroke you should also:

-       Lay the victim on his or her back in a cool, shaded area and move any nearby objects away from the person if symptoms include seizures or fits.  If symptoms include nausea or upset stomach, lay the victim on his or her side.

-       Cool the person’s body by fanning and spraying with a cool mist of water or wiping the victim with a wet sheet.

-       Place ice packs under the armpits and groin area.

Anyone who works in the heat should protect themselves and coworkers through the following tips:

-       Learn the signs and symptoms of heat-induced illnesses and how to respond.

-       Perform the heaviest work during the coolest part of the day.

-       Build up tolerance to the heat and the work activity slowly (usually over two weeks)

-       Use the buddy system, with people working in pairs.

-       Drink plenty of cool water, about a cup every 15-20 minutes.

-       Wear light, loose-fitting, breathable clothing, such as cotton.

-       Take frequent, short breaks in cool, shaded areas to allow the body to cool down.

-       Avoid eating large meals before working in hot environments.

-       Avoid alcohol or beverages with caffeine. These make the body lose water and increase the risk for heat illnesses.

There are other factors that may put you at risk for heat injury. These may include wearing personal protective equipment such as a respirator or protective suit that will retain heat, having a previous heat-induced illness, and taking certain medications.  When on medications, check with your healthcare provider to see if any medicines you are taking affect you when working in hot environments. 

Hopefully these tips will serve as a reminder to us all to slow down and cool off as we get through the remaining weeks of summer.  Keep yourself (and your horse) cool and hydrated every chance you get! 

Preventing Thermal Injury During Hot Weather

Now that we are almost into the “dog days of summer”, horse owners should pay attention to temperature and humidity while exercising their horses. We will likely experience the highest temperatures of the year over the next couple of months, and the humidity can be pretty high in the Southeast during the summer.

As the horse exercises in hot weather, heat builds up in the core.  Blood flow increases to transport that heat buildup to the surface (skin) where hopefully the heat is dissipated.  One way that horses dissipate heat is through sweating.  Sweat is composed of water and minerals, and helps dissipate heat through evaporation and provides evaporative cooling for the horse.  It goes to reason that the more intense the exercise, the greater the heat buildup, and the greater the loss of fluid to sweating is.

Thermal Injury is caused by animal dehydration.  A horse’s water intake can increase 300% with prolonged exercise, and there is a direct correlation between fluid loss, inability to maintain temperature, and onset of fatigue during endurance exercise.  Too much dehydration leads to electrolyte and pH imbalance, fatigue, uncoordinated gait, and increased risk of orthopedic injury or death.

To minimize the risk of thermal injury during exercise, provide plenty of water, adequate salt and minerals, and a good, balanced ration.  After strenuous exercise, allow horses a 24-hour period to rehydrate between exercise programs.

To further minimize the risk of thermal injury, pay attention to weather conditions.  Knowing the temperature and relative humidity allows us to calculate a “comfort index”.  The comfort index is the sum of the temperature in degrees Fahrenheit and the percent relative humidity.  A total less than 130 indicates that thermal injury should not be a concern.  If the score is between 130 and 150, a horse will sweat, but should not incur serious thermal injury.  If the comfort index is over 150 and the relative humidity is over 75%, heat dissipation can be a problem and horses should be monitored closely during exercise.  If the comfort index is over 180, heat dissipation will likely be a problem and the workout should be discontinued or rescheduled.

Under normal conditions, diet and mineral supplementation, along with adequate water, should be enough to maintain electrolyte balance.  However, with intense exercise programs, the horse will sweat a lot, which can lead to water and electrolyte deficiency.  Symptoms include weakness, muscle cramps, acid-base imbalance, and decreased performance. 

As the horse becomes more acclimated to the exercise level, the heat, and humidity, its mechanisms to conserve sodium and potassium improve.  Horses that are not acclimated to heat and humidity, and that are starting a vigorous exercise program should be monitored closely, and may require electrolyte supplementation to avoid thermal injury.

Much of the information in this article and additional information on the topic of thermal injury is available at http://articles.extension.org/pages/25671/responsible-horse-care-for-winter-and-summer by Steven M. Jones, Extension Horse Specialist.

Heat Stress

“Nothing could be finer than to be in Carolina . . .” until it gets hot!  As North Carolinians, we love the summer.  We enjoy being outdoors, camping, swimming, hiking and riding; however, there are a few things that need to be taken into account when deciding whether or not to hit the trails with your horse during the long summer days in NC.

 Hyperthermia, heat exhaustion and heatstroke are all heat related conditions that should be avoided.  Since horses primarily cool themselves by sweating, the higher the ambient temperature and relative humidity, the less likely the animals are to cool themselves during periods of exercise.  As sweat evaporates off of the skin, it cools the body.  High temperatures coupled with high humidity cause increased sweating without the ability to evaporate effectively.  Before saddling up, consider the ambient temperature in degrees °F AND the % humidity, add them together, then consider the following:

·      If the temperature plus humidity is < 130, then the horse’s ability to cool itself will not be compromised.  Exercise and working may continue with no problems.

·      If the sum is 130 – 150, the ability is decreased somewhat and precautions should be taken to make sure that the horse does not overheat.

·      Sums over 150 indicate that the ability to cool is greatly reduced so exercise/work time AND the intensity of the sessions should be shortened.

·      If the sum is 180 or over, cooling ability is almost nonexistent and heat stroke is likely if animals are stressed.

Throughout the summer ride during the early morning or late afternoon hours when temperatures are typically cooler.  Provide fresh, cool water throughout the workout session but make sure that the horse is taking smaller sips and not large gulps of water.  After your session, cool your horse with a spray-down ensuring that you scrape off the excess water immediately.  Work in the shade if possible and use fans to create airflow in barns and stalls if little to no airflow exists.  Check your horse’s vital signs if you suspect overheating.  The rectal temperature should be between 99.5 °F to 101.5 °F at rest and no higher than 103 °F during work.  Normally, their pulse should be 30-44 beats per minute at rest and their respiration rate 8-12 breaths per minute.  Anything higher than these numbers should be monitored closely, work should be terminated and if vitals do not return to normal within 15-20 minutes, a veterinarian should be called.

Our state has a lot to offer equestrians throughout the year so by all means, take advantage of the opportunities, just be cognizant of the temperatures and humidity, adjust activities as needed and stay safe.