August 8, 2016 • CoachingStrength & Conditioning

Using caution in the summer heat

Coaches of outdoor fall sports are currently in the process of training their athletes in the heat of summer. Soon, especially in football, athletes will be engaged in full-gear, full-speed practices.

Powerline HeatFor the most part, these coaches have been educated — and need to renew their certifications with regularity — in heat acclimatization protocols, First Aid, CPR and AED use. The subject of summer training safety is one that can never be overstated. Education, on the part of coaches, parents and athletes, should be ongoing and continually refreshed. Anything less borders on egregious.

In this installment of Powerline, I’ll cover several crucial issues related to training in the heat, and offer evidence-based advice on avoiding serious problems with your athletes.

Potential problems

Exercising in the heat presents a tremendous challenge to the body’s regulatory systems. When an athlete is training in the heat with a high degree of physical effort, the metabolic rate can increase 20 to 25 times higher than it would be in a resting state. Increased heat production from the required muscular work raises the internal temperature, resulting in accelerated cardiac output, dilated blood vessels, the shunting of blood from the internal organs to skin, and the obvious stimulation of sweat glands.

When training in extremely hot and humid conditions, sweat does not evaporate as readily, thus negatively affecting the body’s natural cooling mechanism and decreasing blood plasma volume, which is adverse to performance due to decreases in stroke volume.

In the case of football, when it’s time to don helmets and full-pads, the following situations occur exponentially: Increased heart rate, evaporative cooling is reduced, sweating increases, rectal temperature rises, skin temperature increases, and peripheral blood flow and heat conductance can increase two-fold. Individually or collectively, these occurrences can lead to very serious physical problems.

Troubleshooting strategies

It can take, on average, 10 to 15 days of exercise heat exposure for the body to gradually acclimate to those conditions. Simply put, the body adapts by reducing rectal temperature, lowers cardiovascular strain, increases plasma volume, and hence, there is a reduction in “rate of perceived exertion” (RPE), or one’s vocal expression of the degree of physical stress he or she is experiencing at any given moment. Go to and search for variations of Borg’s RPE Scale.

Many strength and conditioning coaches and sports medicine specialists recommend a minimum of three to four weeks, at a clip of two to four days per week, of gradual, progressive acclimatization via summer conditioning leading up to the start of practice. In these sessions, careful attention must be given to the intensity, volume, duration and tempo, with a scripted, definitive progression plan for each of these indices. Gradual and progressive are the operative words in this process. This is not to say that you should pick the hottest time of day to train; initial sessions should be held at cooler times, with a gradual transition to warmer times.

Experts in this area indicate that virtually all of the catastrophic heatstroke incidents occur in non-acclimatized players during the initial three days of summer practice. This validates the prescription of gradually increasing the frequency, volume, intensity, tempo and duration of both conditioning sessions and full practices.

In football, high schools and colleges are required to initiate the first few practices in helmets, shorts and T-shirts only — no heavy protective gear. Once full protective gear is utilized, checks and balances on intensity, tempo, duration and practice frequency must remain in full effect. Whenever possible, and most certainly in the initial phase, practices should be held at the cooler times of day.

Additionally, in both high school and college, there are definitive rules on two-a-day practice sequences. Basically, back-to-back days of two-a-day sessions are prohibited. It’s a ruling that has been long overdue.

Personally, I look forward to the day when two-a-days are a thing of the past. I adamantly believe that we will have fewer injuries, reduce the ill-effects of overtraining, and allow for more recovery time in all of the vital systems of the body.

When it comes to hydration, a big problem regarding fluid intake is that many athletes do not start drinking during workouts or practices until they are thirsty. Unfortunately, thirst is not an accurate indicator of hydration status. This can be compounded by the fact that dehydration slows gastric emptying, so waiting to drink until the thirst mechanism activates is a negative double-whammy.

Impress upon your athletes to drink early and often during these sessions, and be sure that there is ready access to fluids. Scheduling fluid breaks during longer conditioning and practice sessions — and insisting the athletes drink — are excellent approaches to abating the issue of dehydration. Also, self-checks on urine color can be an evaluator. Keeping in mind that urine color can be affected by vitamins and other supplements, urine should be relatively clear or slightly yellow. A deep yellow hue might indicate dehydration.

Electrolyte balance is a key player in the hydration game. Athletes lose a large amount of electrolytes, especially sodium, in their sweat. In football, the bigger players (i.e., offensive/defensive linemen) can lose substantial fluid due to high sweat rates. A post-practice weight loss of greater than 2 percent requires an intervention strategy to regain that fluid. Sodium loss in this process is a huge problem, as body fluid balance and the thirst mechanism heavily rely upon it. High sodium losses can equate with heat illness, muscle cramping and impaired nerve function.

Water is undoubtedly a vital component in preventing dehydration, but keep in mind that electrolyte-laden drinks should also be in the mix. This helps corral the loss of sodium and the health issues that condition presents.

As a basic rule of thumb, players need to consume about 24 ounces of fluid for every pound lost (via post-activity weigh-in) during conditioning sessions, practices or games. Making at least a portion of this an electrolyte solution is highly recommended. Pre/post weigh-ins during heavy practice times, especially when wearing full-gear, is imperative for monitoring purposes.

Hyponatremia is a condition that occurs when the level of sodium in your blood is abnormally low. There have been reported cases of hyponatremia attributed to drinking too much water prior to, or during, athletic events, primarily long distance, endurance-type competitions (e.g., marathons and triathlons). This is why fluid intake and weight monitoring should be directed, administered and evaluated under the auspices of certified athletic trainers (ATCs) or other trained professionals.

Recommended actions

While common sense should prevail in the prevention of heat-related problems and catastrophes, it is imperative that definitive protocols, policies and procedures are in effect.

The following represent the minimum requirements when developing this plan.

  • Presence of ATCs or sports medicine personnel. All teams conditioning or practicing in any environment, especially in heat and humidity, should have immediate access to either an ATC or other qualified individuals to detect signs of impending heat illness, or to initiate the required emergency treatment in such an event. All emergency protocols, directives and contact numbers should be posted in highly visible areas.
  • Track the heat index. The heat index is the apparent temperature you feel based upon the air temperature and relative humidity. A staff member should track this index daily and decisions should be made on the timing, intensity, tempo and duration of conditioning or practice sessions. It must be understood that the body normally cools itself by perspiration, and high relative humidity reduces the evaporation rate. This can lead to serious heat-illness complications.
  • Continuing education. At the scholastic level, team physicians or ATCs should conduct yearly, mandatory educational programs for coaches, players and the athletes themselves on exertional heat-illness and hydration protocols. At the collegiate and professional levels, these programs are ongoing throughout the year.
  • Coach reinforcement. Coaches need to constantly reinforce and educate athletes on refueling, rehydrating and cooling techniques to enhance recovery between practices, especially during two-a-day situations. Additionally, education on the possible adverse side effects of various dietary supplements and medications must be on the docket. All dietary supplements should be approved by the team’s registered dietician, ATC or physician.
  • Coach certification. Coaches working with athletes in any sport and any age level should be certified in First Aid, CPR and AED use. These, along with a solid knowledge of recognizing and responding to exertional heat-related issues, should be required and a mainstay.
  • Sickle cell trait screening. Though not a disease, sickle cell trait (SCT) refers to the inheritance of one gene for sickle hemoglobin and one for normal hemoglobin. Hemoglobin is the molecule in red blood cells that carries oxygen.

In those who have SCT, it’s possible for the red blood cells containing the sickle hemoglobin to change shape from round to a quarter-moon, or “sickle” shape. When numerous cells in this shape accumulate during intense physical activity, normal blood flow can be blocked. Heat, dehydration, asthma and altitude can all exacerbate the complications of SCT, even when the activity does not appear to be overly stressful.

SCT occurs in about 8 percent of the U.S. African-American population, and somewhere in the range of one-in-2,000 to one-in-10,000 of the Caucasian population, according to the NCAA. While those with SCT must be constantly monitored, and with modifications being implemented into their training and practice sessions, there is no need to exclude them from participation. It is vitally important, however, to identify these individuals through a simple SCT screening procedure. This should be part of the standard operating procedure with all athletes, regardless of age or level of play.


An overview of exertional heat-related problems

There are several conditions that are categorized as stemming from either heat or humidity exposure or physical activity in such an environment. It is important, from both personal and professional perspectives, that all coaches are aware of the signs, symptoms and necessary responses for each.

  • Heat rash. While not as serious as other conditions, this “prickly heat” situation can occur when the sweat ducts become blocked or swell, causing itching and discomfort. Keeping the area as cool and dry as possible are the initial treatments. If it persists, medical attention is necessary.
  • Heat cramps. These can be caused from neuromuscular fatigue or excessive sweating. That results in electrolyte loss, with salt being the most significant, but also including potassium and magnesium. Hydration techniques with both water and electrolyte solutions, practicing in cooler environments, taking periodic breaks, and adequate recovery and rejuvenation strategies can help abate this situation.
  • Heat syncope. This is a situation where the individual may faint due to the lowering of blood pressure as the heat causes the blood vessels to dilate and body fluids move into the legs. Move the individual to a cool area, having them sit or recline, and remove as much clothing as possible while administering some cool fluids as tolerated.
  • Heat exhaustion. Also known as heat prostration, this condition is characterized by heavy sweating; overall body weakness; cold, pale and clammy skin; and possible nausea or vomiting. The pulse will be fast, but weak. This individual should be moved to a cool location, loosen or remove as much clothing as possible, and apply cool, damp cloths to exposed skin areas. If there is no nausea or vomiting, cool fluids can be administered as tolerated.
  • Heat Stroke. This is a medical emergency. Call 911 or the emergency contact number indicated in your policies and procedures handbook.

The body temperature can be 103 degrees or higher, and the skin is hot, red and relatively dry. The pulse is rapid and strong. The victim may seem disoriented, nauseated and complain of a severe headache. In an extreme case, the victim may be unconscious.

Until qualified emergency personnel arrive, move the person to a cool area and place in a comfortable position, remove as much clothing as possible. Also, lower the body temperature with cool compresses, or shower and ice packs. Do not administer anything orally, including fluids. If unconscious, be sure the airway is clear, especially if the individual had been vomiting.

Ken Mannie is the head strength and conditioning coach Michigan State University. His column, Powerline, appears regularly in Coach & Athletic Director magazine. 

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