Youth Lacrosse for Western Prince William County

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NVYLL Heat Guidelines
Insurance 101: Heat-Related Injuries ~ Prevention and Treatment
One of the biggest concerns for summer lacrosse players is preventing heat injuries. Heat-related injuries, such as heat exhaustion or heat stroke are emergency conditions that need immediate treatment and medical care. However, such incidents can be prevented with a few simple steps, which are described in this article to keep coaches, players and officials in the game.
What are Heat-related Injuries?
Normally, our bodies produce a tremendous amount of internal heat, which is cooled by sweating and expelling heat through the skin. When there is extreme heat, high humidity or vigorous activity in the hot sun, this cooling system may begin to fail, and allow heat to build up to dangerous levels. Heat injuries manifest themselves in a number of forms, from mild symptoms to life-threatening conditions.
• Heat Cramps: Heat cramps are muscle contractions, usually occurring in the calf or hamstring muscles. These contractions are forceful and painful. They are typically related to heat, dehydration, and poor conditioning. Treatment for cramps is simple: rest, drink water and get to a cool environment.
• Heat Exhaustion: Heat exhaustion stems from excessive heat and dehydration. Its symptoms can be detected in the appearance and activities of your players during practice or a game. The range of symptoms includes nausea, dizziness, weakness, headache, heavy perspiration, normal or low body temperature, weak pulse, dilated pupils, disorientation, and fainting spells. Treat heat exhaustion by getting the person to a cool or shady environment, drinking liquids and applying cool water or ice to the body. Most people respond to these treatments, but prompt attention is necessary in order to prevent the condition from progressing to heat stroke. More severely heat-exhausted patients may need IV fluids, especially if vomiting keeps them from drinking enough.
• Heat Stroke: Heat stroke, the most serious form of all heat-related conditions, is a life-threatening medical emergency. A person with heat stroke usually has a very high temperature (over 104 degrees) and along with the other symptoms above, may be delirious, unconscious or having seizures. These patients need to reduce their temperature quickly and must also be given IV fluids for rehydration. Take them to a hospital as quickly as possible – although cooling treatments need to be started immediately and continue until emergency medical personnel can take over. In addition to applying ice, another effective form of cooling in this case is “evaporative cooling” where the person is sponged or misted with cool water, and fans are used to circulate the air around the person to encourage rapid evaporation.
Lacrosse Players are Vulnerable
Because lacrosse is a warm-weather running sport, lacrosse participants are at risk for heat illnesses. Coaches can take a number of steps to prevent heat-related injuries among their players:
1. Recognize the dangers of playing in the heat.
2. Schedule regular fluid breaks during practice and games. Players should be hydrated prior to the start of games or practices and to continue to drink eight ounces of fluid every 20 minutes during the activity with water or sports drinks.
3. Players should avoid soda, caffeine drinks and alcohol before or during games, as these can promote dehydration.
4. Make player substitutions more frequently in the heat.
5. Have players wear light-colored, “breathable” clothing.
6. For boys & men, take “helmet breaks” every 30 minutes to ensure that heat in the helmets gets released. Just as your mother told you to wear a hat in winter so “90% of the heat would not be lost through the top of your head,” the converse is true in summer – wearing a helmet keeps in a great deal of heat that the body is trying to expel.
7. Use misting water sprays to keep players cool.
8. In the early part of the season, particularly in warm, humid climates, acclimate players slowly to the heat. Play at cooler times of day, and build up players’ tolerance to heat a little more each day. If you are attending a camp or tournament in a climate that is hotter than you are used to, go early (if possible) to help the team adapt and be vigilant about enforcing preventative measures.
9. And always, respond quickly if heat-related injuries occur.
For more information on safety and risk management, or to see prior Insurance 101 articles, please visit the US Lacrosse Insurance and Risk Management web site at
Lori Windolf Crispo, CPCU is the Executive Vice President in charge of Bollinger’s Sports Insurance Division. Bollinger is the insurance administrator for US Lacrosse. Contact her
Environmental factors:
Ambient air temperature and humidity have a direct effect on the ability for a body to cool itself through the evaporation of sweat. When the air temperature is above 90, and/or the relative humidity is high, the body is at a higher risk to not effectively stay cool, which may be compounded by the level of dehydration of the body’s fluids.
The following chart is a simple method to determine the amount of increased risk with variations of heat and humidity, and subsequent suggestions to modify participation in physical activities.
The below chart can be used by inputting the temperature and humidity available via local radio stations, Internet locations, or local field measurements. Simply cross-reference the relative humidity with the temperature to determine the apparent temperature. NVYLL member clubs practice in the evening and the ambient conditions progressively improve as we move into the evening, however, reasonable cautions need to be implemented as the conditions warrant. At a minimum, commissioners should implement the following guidelines as outlined below when a particular field condition exists.
A number of factors will make each clubs environmental conditions unique to their home fields. NVYLL fields are spread over an approximately 2400 square mile area in Northern Virginia. On any given day the temperature and humidity can vary significantly across the many different NVYLL fields. Additionally, whether a field has natural or artificial turf (AT) can make a significant difference to the conditions a player experiences. AT surfaces have been reported to be 10 - 50deg hotter than similar natural turf fields. It is recommend that Clubs with AT fields use local field measurements utilizing a Sling Psychrometer* to determine temperatures and humidity levels players will experience.
* Sling Psychrometers may be purchased on-line from various scientific instrument vendors. Prices range from $60- $150.

105º and up:                         Recommend no outside activities. At a minimum, individual clubs must
(CODE RED)                       implement heat injury risk mitigation measures.
95º to 104º:                           Recommend no equipment except helmets (pads, etc) be used during practice. For games, additional non-chargeable time-outs should be called by the officials to allow for additional hydration opportunities (see below). Shade should be made available for players if possible.
90º to 94º:                             Recommend equipment (helmet at a minimum) be removed as often as possible (during rest breaks, on sideline, etc). Careful monitor all athletes for signs of heat problems.
Below 89º:                            Recommend adequate water supply at all practices and games with breaks every 20
to 30 minutes for rehydration.
Water breaks of no greater than 1:30 minutes in length will be incorporated into each game if, in the opinion of attending medical personnel, referees and/or the Field Commissioner, they become necessary. In women’s play, those breaks will be taken as close to the mid-point of each half as possible after a goal or during a dead ball situation. In men’s play, those breaks will be taken as close to the mid-point of each quarter as possible after a goal or during a dead ball situation.
National Athletic Trainers Association’s Recommendations on Fluid Replacement:
• Educate athletes on the effects of dehydration on physical performance.
• Inform athletes on how to monitor hydration status.
• Convince athletes to participate in their own hydration protocols based on sweat rate, drinking preferences, and personal responses to different fluid quantities.
• Encourage coaches to mandate rehydration during practices and competitions, just as they require other drills and conditioning activities.
• Have a scale accessible to assist athletes in monitoring weight before, during, and after activity.
• Provide the optimal oral rehydration solution (water, CHOs, electrolytes) before, during, and after exercise.
• Implement the hydration protocol during all practices and games, and adapt it as needed.
• Finally, encourage event scheduling and rule modifications to minimize the risks associated with exercise in the heat.
Journal of Athletic Training Vol. 35 N2, June 2000
Full text can be found on NATA’s website:
Acclimatization to Heat:
Another way to help prevent heat stress is to become acclimatized to the weather. Acclimatization means becoming adapted to the weather or climate. The process takes 7 to 12 days. Studies have shown adolescents take longer to acclimatize to heat than adults. As a result of acclimatization, the sweating mechanism of a person is enhanced:
• onset of perspiration occurs earlier
• perspiration increases
• increase in blood volume with the more training an individual does
• improves supply of oxygen to the muscles
• heart rate decreases
• core body temperature does not rise as high during exercise
Other facts about heat illnesses and exercising in the heat:
• Dehydration of 1% to 2% of body weight begins to impact athletic performance
• Dehydration greater than 3% of body weight may increase an athlete’s risk of heat illness.
• Sports drinks should contain less than 8% carbohydrate. Carbohydrate content greater than 8% compromises the rate of gastric emptying and should be avoided.
• Wear light weight and light colored clothing
• Avoid wearing articles that prevent water absorption
• Early morning commonly produces a humid environment and lower temperatures. Usually, as the sun rises, the temperature will increase and the humidity decreases. As the evening hours approach, the temperature decreases and the humidity will rise. Often, the most critical times to monitor athletes ability to exercise in hot weather occurs when the temperature rises quickly during the early morning prior to the sun burning off the humidity, or during storms when the humidity remains high due to cloud cover, etc.
• A mild breeze can reduce the humidity on a particular field, as well as improve the evaporative process.
• Field watering after practice sessions are complete can help reduce the ambient humidity on or near an athletic field, thus reducing the heat stress on athletes.
Fluid Consumption
2 hours
Full gear
Insist that adequate water be ingested
Never restrict water consumption
2 hours
Full gear
Insist that adequate water be ingested
Provide minimum of 2 water breaks per hour
2 hours
Full gear
Insist that 4 – 6 oz minimum water be ingested every 20 minutes
Provide minimum of 3 water breaks per hour
2 hours, every 45 minutes of work > 15 minutes of rest each hour
Remove helmets unless active in drill
Insist that 8 – 10 oz water be ingested every 15 minutes
Remove helmet unless active in drill
2 hours, every 45 minutes of work > 15 minutes of rest each hour
Protective equipment removed for non-contact drills
Insist that 8 – 10 oz water be ingested every 15 minutes
Removal of helmet unless active in drill, removal of pads (ie: shoulder pads) when teaching or non-contact portions of practice exceed 10 minutes in length
Fluid replacement should be at a rate of 24 oz for every pound of body weight lost after exercise.
• Light colored, loose clothing is suggested during activity in hot weather.
• Athletes are encouraged to wear sunscreen on exposed skin during hot, sunny conditions.
• Adequate fluid supply should be readily available at all times during activity in hot weather.
• Individuals poorly acclimatized or poorly conditioned are at increased risk for heat related illness/injury and    should be monitored closely or placed on a modified participation schedule.
• Athletes having a pre-existing dehydrated state (recent fever or gastro-intestinal illness) or pre-existing heat    injury are at a much higher risk for heat related illness/injury and should be monitored closely or placed on a    modified participation schedule.
• Medications including diuretics, antihistamines, beta-blockers and anti-cholinergics increase the risk of heat   illness/injury.
• Overweight athletes are at increased risk for heat illness/injury and should be monitored closely.
• Energy, ergogenic, and dietary supplements such as Creatine may cause an increase in dehydration and heat    related illness and/or injury.
• Providing shade on the sidelines is a way to allow players to more effectively cool off during time off the field.
• Commissioners may allow extra support personnel to be present on the sidelines in order to better hydrate players and monitor their physical condition.