Jan 26, 2017Cold Hard Facts
Adam Perrin, MD, FAAFP, practices primary care sports medicine in Hartford, Conn., where he is affiliated with Middlesex Hospital and Saint Francis Hospital and Medical Center. He is also an Assistant Clinical Professor of Family Medicine at the University of Connecticut School of Medicine.
In the past decade or so, athletic trainers and sport coaches have become quite well versed in the dangers of heat illness. Terms like core body temperature, heat index, and prehydration have become part of the athletic training lexicon, as everyone now understands the health hazards associated with working out in hot, humid conditions.
At the other end of the thermometer, however, far less attention is paid to injury risk from cold exposure. While it’s true that more competitive athletes nationwide suffer from heat illness each year than from severe hypothermia or frostbite, there are significant risks for those who train and compete outdoors in the winter months. Everything from respiratory function to mobility and even eyesight can be adversely affected when athletes are exposed to extreme cold.
Fortunately, virtually all cold-related injuries and illnesses that threaten athletes can be prevented if athletic programs take the right precautions. By understanding the different types of risks and how to face them, athletic trainers can prepare their athletes for safe participation, regardless of the sport or mercury reading.
FROSTNIP TO FROSTBITE
In January 2004, Ball State University sophomore wide receiver Chris Jackson was hospitalized and treated for frostbite on his fingers after a morning workout. The air temperature that morning was -7 degrees Fahrenheit, and the wind chill was -12. Jackson made a full recovery, but his head coach and the football strength and conditioning coach received letters of reprimand from the athletic director for conducting the workout under such dangerous conditions.
When most people think of frostbite, they think of mountain climbers or skiers–not football players. But as the Ball State case illustrates, many types of athletes can be at risk. It’s hard to know how many athletes suffer from frostbite because many mild cases go unreported, but any sport that combines cold weather with wet skin and clothing can pose a threat, including football, crew, and soccer, to name a few.
Frostbite is a localized tissue injury that occurs when tiny ice crystals form in the skin or other tissue. The most frequently affected body parts are the hands and feet, followed by the “watershed” sites of the nose, ears, cheeks, and occasionally the corneas. In clinical terms, it is usually defined as being either mild (superficial) or severe (deep), and assigned a degree of severity from first through fourth, just as in burn classification. However, it is often impossible to tell how severe a case of frostbite is until after rewarming.
What environmental conditions put athletes at risk for frostbite? Not surprisingly, low air temperature and wind chill are the primary factors, along with prolonged exposure.
The mildest form of frostbite, frostnip, typically presents as cold, pale skin, usually accompanied by a mild burning sensation followed by numbness. After an individual is removed from the cold, these symptoms are short-lived and there is no tissue damage. With more severe frostbite, the affected body part is initially cold, firm, and pale. A severe frostbite victim will often complain of numbness, followed by extreme throbbing pain during rewarming. Some degree of sensory loss is experienced by almost all frostbite victims, and in severe cases, it can last up to several years.
What environmental conditions put athletes at risk for frostbite? Not surprisingly, low air temperature and wind chill are the primary factors, along with prolonged exposure. Wet skin and clothing are also major contributing factors, since water promotes heat transfer through evaporation–anyone who’s walked outside in wet clothing on a wintry day understands this effect. Impaired peripheral circulation can also be a problem, with tight-fitting, restrictive clothing potentially hindering blood flow.
The treatment for cases of suspected minor frostbite is fairly straightforward. The athlete should be removed from activity and the affected body part should be placed in water 102 to 108 degrees Fahrenheit for 15 to 30 minutes or until the skin has regained its normal color and any numbness has resolved. If any clear or white blisters develop, they should be cleaned and debrided, and the site should be covered with topical aloe vera every six hours. Hemorrhagic blisters should be left intact and covered with aloe vera. Ibuprofen (400 mg every six hours) can be used to inhibit inflammation, and tetanus immunization is recommended. An athletic trainer or physician should closely monitor the affected area after return to play, and at any sign of recurrent frostnip or frostbite, the athlete should be removed for the remainder of the event.
More severe frostbite requires immediate medical attention, preferably at a hospital. A broad-spectrum antibiotic or IV analgesia may be necessary, and usually some degree of surgical intervention will be needed as well.
Any time you suspect an athlete may be suffering from more than frostnip, he or she should be immediately removed from activity. Do not attempt rewarming until there’s no risk of further cold exposure, as this can lead to more serious tissue damage. It’s actually better to have an athlete walk on frostbitten feet to an indoor facility than for them to walk on partially rewarmed feet. In addition, do not massage frostbitten tissue.
Return-to-play decisions should be made by a doctor. In most cases, return will not be allowed until blisters are completely healed and the affected tissue has normal sensation and range of motion.
NON-FREEZING COLD INJURIES
Even when the mercury is above 32, cold and wetness can lead to problems for athletes. In recent years, non-freezing cold injuries (NFCIs) have become more prevalent as the number of participants in higher-risk cold weather sports has increased. NFCIs do not involve tissue freezing, which distinguishes them clinically from frostnip and frostbite.
One of the most common NFCIs for athletes is chilblains, also known as perniosis. These bluish-red inflammatory skin lesions are caused by an abnormal reaction to a cold, damp environment. They are typically localized to the dorsal parts of the feet and are seen most often in adolescents and young adults (under the age of 20)–especially females. The symptoms of chilblains include an itching or burning sensation that often gets worse with warming. While not as serious as frostbite, these lesions and the resulting discomfort can negatively impact athletic performance.
The recommended treatment for chilblains is to dry and gently massage the affected skin region. Active warming should be avoided, as it will significantly worsen the pain and won’t expedite healing. A low potency anti-inflammatory cream, such as one-percent hydrocortisone, can be used to reduce discomfort both immediately and as the skin heals. Chilblains usually resolve within one to three weeks.
The best way to prevent chilblains when athletes are training or competing in cold weather is to keep the skin warm and dry. Replacing the innermost layer of clothing with a dry layer when it becomes wet during activity is helpful. While sometimes painful, chilblains are not as serious as frostbite–athletes can return to play as soon as they feel comfortable doing so.
Another NFCI is immersion foot (also known as “trench foot”), though this is rare in the sports world because it requires exposure to damp and cold conditions for a longer period of time than athletes typically experience. Like chilblains, immersion foot can occur even when the temperature is well above freezing. It is characterized by discoloration, soreness, and swelling of the affected area. To guard against immersion foot and simply for athlete comfort, those who are active in cold, wet conditions for an extended period of time should change their socks frequently.
Raynaud’s phenomenon is yet another NFCI that should be on an athletic trainer’s watch list. It’s an episodic spasm of blood vessels (vasospasms), usually in the fingers, and is a fairly common response to cold, particularly among young women. The affected digits become cold, pale, and numb (similar to frostbite), followed by a hyperemic phase characterized by redness, throbbing pain, and swelling.
To prevent Raynaud’s, the trunk should be well insulated and the hands should be adequately protected when athletes are working out in cold weather. For more severe cases, a doctor may prescribe an oral vasodilator as a preventive measure. Acute attacks can be treated by warming the affected part, but any athlete who suffers from Raynaud’s should have a thorough medical evaluation to rule out underlying conditions such as collagen vascular disease.
In rare cases, an athlete may suffer from cold-induced urticaria. With this condition, hives appear, usually during warm-up, and resolve within an hour after the athlete is removed from the cold. He or she may continue to train or compete, provided swelling does not get worse.
Exposure to cold, dry air during athletic participation is a common trigger for exercise-induced bronchospasm (EIB). This condition is characterized by difficulty breathing and is caused by the constriction of muscles that surround breathing tubes in the respiratory tract. EIB can strike virtually any athlete who exercises in cold conditions, such as cross country runners, field hockey players, and soccer players.
Nasal breathing and wearing a mask or scarf around the nose and mouth will warm and humidify inhaled air, thus helping to diminish EIB. Attacks can usually be prevented through the use of an inhaled short-acting bronchodilator such as albuterol, which can be prescribed by a physician after a diagnosis of recurring EIB. This medication is most effective if administered 30 to 60 minutes prior to exercise.
Although it will not prevent EIB, conditioning may reduce the severity of attacks, so proper warm-up and cool down during strenuous exercise sessions can help. Sports that involve frequent pauses, such as football and baseball, and low-intensity activities are less likely to trigger EIB, and for reasons that are not well understood, short bursts of vigorous exercise can sometimes help diminish bronchospasm.
Athletes who are suffering from a respiratory infection caused by bacteria are at risk for a condition called cold-agglutinin disease. It can result in cyanosis (a bluish coloration of the skin), pain, and numbness in exposed body parts due to a reaction between red blood cells and antibodies activated by cold exposure. This condition is usually self-limited and can be treated by simply removing the athlete from the cold. Return to play is dictated by the severity of the associated respiratory infection.
People with asthma are especially susceptible to respiratory problems when working out in cold, dry conditions, and this is a growing concern in the sports medicine community. In one recent study, researchers from the Ohio State University Medical Center found that 39 percent of college athletes they screened for breathing problems suffered from some form of exercise-induced asthma. A large majority of those had no history of the illness, which suggests many athletes with asthma may not know they have it.
Any time an asthmatic athlete experiences breathing difficulty, he or she must be removed from the cold immediately. The athlete should follow a physician’s direction when using prescribed albuterol or a similar agent, and should not return to activity until symptoms fully resolve. Severe attacks may require a visit to the emergency room, so all necessary precautions should be taken when, for instance, a cross country team will be going on a long run away from campus.
Both the NCAA and the International Olympic Committee list aerosol albuterol as an approved treatment for asthma if prescribed by a doctor. However, it’s important to remember that many similar agents–including some long-acting treatments for asthma–are banned. Always research the medication your asthmatic athletes are using to ensure that they’re not risking disqualification or other sanctions.
Common sense tells us the best defense against all these potential problems is to get out of the cold, but that’s not always a realistic solution. Luckily, some simple precautions can go a long way toward keeping athletes safe from cold injuries.
One of the most important preventive steps is minimizing body heat loss. Wearing multiple thin layers works well for most outdoor sports by creating a buffer of warm air around the body. The best fabrics for cold weather are those with high insulating properties.
Wetness is a main contributor to many types of cold injury, since water conducts heat 25 times faster than air, so keeping athletes dry is critical. For the innermost layer of clothing, a synthetic fabric that wicks away moisture is ideal. Protection from both wind and wet conditions can also be provided by windproof and water-repellant apparel, such as a jacket and pants made with “windbreaker” material.
When athletes will be outdoors in the cold for any length of time, attention must be paid to protecting special body parts. Because blood supply to the head is not decreased by cold exposure, considerable heat loss occurs if the head is left uncovered. A quality hat (or helmet depending on the sport) that also covers the ears is vital. In fast-moving sports such as cycling and downhill skiing, eye protection is essential, particularly when cold combines with wind. At extreme temperatures, contact lenses may actually freeze to the eyeball, and severe cold-related corneal injury may even result in blindness. Female athletes should wear insulated bras to protect nipples, and male athletes should wear shorts with insulated, windproof front panels to help prevent cold injury to the genitals.
For skiers in particular, boots are a special concern. The tight “race-fit” boots used by some downhill skiers pose a particular risk for frostbite. The ideal boot would fit perfectly, be waterproof, expand when the foot swells, allow transfer of water vapor to maintain dryness, and have excellent insulating properties and flexibility. Moisture-wicking socks can be extremely helpful, and boot heaters should be seriously considered by any skier who has a history of frostbite or NFCI.
Finally, every athletic program should make responsible decisions about when to move a practice indoors or cancel an early-morning run because of cold weather. Remember that not just air temperature but also windchill, the type of activity, and the duration of exposure all contribute to the level of risk. Wet bulb globe temperature (WBGT) is an excellent guide for determining when it’s safe to train outdoors, because it factors in temperature, humidity, wind speed, and radiant heat. Risk for cold injuries increases whenever the WBGT drops below 50 degrees Fahrenheit, and outdoor events should be canceled if the WBGT falls below -4 degrees Fahrenheit.
As an athletic trainer, you are in the best position to make sure athletes are protected. Some coaches may believe that working out under harsh conditions will help athletes “toughen up” (Vince Lombardi once famously said that “frostbite is for losers”), but this attitude is no longer acceptable. With the right combination of awareness, responsiveness, and common-sense prevention, athletes can remain safe in any climate.
This article first appeared in the November 2007 issue of Training & Conditioning.