During football practice last September 23, Harold Coxson, a 17-year-old Dallas high school player, collapsed and lost consciousness. The cause was heatstroke. Shortly afterward he was admitted to a hospital, where his temperature was found to be 109°. Prompt medical attention reduced this to 102° by the following morning, and he survived.
Harold Coxson was among the lucky ones. Since 1959 there have been nine documented cases of the deaths of high school and college football players directly attributable to heatstroke. In addition, heatstroke is believed responsible for the deaths of two other college players, one high school boy and one semipro player. This ailment, to which football players are particularly susceptible, is a breakdown of the sweating mechanism that occurs when the body is unable to throw off excessive internal heat efficiently. As a result, body temperature soars at a rapid and dangerous rate.
The deplorable fact is that in every one of the 13 cases death was preventable. This is the conclusion of Ohio State University physiologists and medical doctors who have just completed a four-month study of the effect of heat stress on players. Highly significant was their finding that the uniform and helmet—marvels of efficiency in protecting the wearer from physical damage—were major factors in causing heatstroke and heat exhaustion. Said participating physician Dr. William F. Ashe, one of the world's foremost authorities on heat stress, "Under certain conditions, the uniform can be a death trap."
The research team, under the direction of Dr. Donald K. Mathews of the OSU physical education department, began its work with a detailed examination of the player deaths in the light of certain basic medical facts: When a person's temperature reaches 106°, his central nervous system cannot cope with the heat load it must carry. His skin becomes dry and warm (sweating having ceased), and he may develop a staggering gait before falling down unconscious. Death is very likely when the temperature reaches 110°. Fully half the cases of heatstroke are fatal.
November 25, 1963
In cases where a person's life is saved—by quick, competent attention, with emphasis on reducing the victim's temperature—brain damage may still occur. Most frequently, the hypothalamus is injured. This is a tiny nucleus of nerve cells in the center of the brain that acts as a kind of thermostat for the body, regulating the throwing off of heat or the conserving of heat, depending on the body's needs. If damaged by an excessive heat load, the hypothalamus may lose its delicate temperature-regulating ability. Victims of hypothalamus damage are unable to adjust to extremes of heat or cold that would not endanger a normal person.
Heat exhaustion—another syndrome to which football players are especially susceptible—is characterized by profuse sweating, sudden weakness and perhaps headache, irritability and nausea. The number of high school and college players who, during practice or in a game, are felled by heat exhaustion is not known, but an estimate by Dr. Mathews places it annually in the high hundreds. One of the dangers of heat exhaustion is that it can turn into heatstroke. A player gets red in the face, continues to sweat, develops a high pulse rate and a slight fever. As his temperature rises still higher, he begins to feel better. This is an illusion. He suddenly stops sweating, gets goose pimples and his temperature soars. At about 106° he becomes unconscious. Heat exhaustion, asserts Dr. Mathews, is likewise preventable.
In carrying out his research, Dr. Mathews was aided by several graduate students working on Ph.D.s in physiology. Also on the investigating team were Wayne Kaufman, supervisor of athletics for Cuyahoga Falls, Ohio schools, Dr. Edwin Hiatt, a renal and cardiovascular specialist, and Dr. Ashe, who is chairman of the department of preventive medicine at OSU and has studied the effects of high temperatures on factory workers in India and miners in South Africa. Finally, several high school football players and OSU students and graduate students volunteered as guinea pigs for experiments with the football uniform.
Specifically, the research team wanted to find out how much heat the football uniform retained, how much sweat it allowed to evaporate, how much of a heat load was induced and, most important, what the physiological changes were. It is widely understood, of course, that the principal way in which a person throws off excess heat—be he football player or clerk—is by sweating. Evaporation of sweat cools the blood, which has carried internal body heat to the surface, thus lowering the body's internal temperature. The more efficiently the body sweats, the more efficiently it is cooled. When sweat is prevented from evaporating, however—by high humidity or lack of movement in the air, or when trapped by clothing that stops air from reaching it—the body's temperature rises rapidly.
It is also known that when the body sweats to an unusual degree, a fairly sizable amount of salt is lost along with water and that this salt must be replaced. The more water a person gives off, the greater his oral salt intake should be. A common symptom of excessive loss of salt through sweating is a cramp in one or both calf muscles. Sometimes the cramp can be brought on by drinking large amounts of water without taking salt at the same time. The combination of losing salt and water by sweating and replacing them with water alone will cause an imbalance affecting the behavior of certain skeletal muscles.
In their examination of the fatal heatstroke cases, the research team found that the nine players, who ranged in age from 17 to 20, were typical as to height and weight. They ranged from 5 feet 8 inches to 6 feet 1½ inches, and from 165 to 244 pounds (the heaviest player was also the tallest). On the days that they were stricken, humidity was relatively high, ranging from 43% to 100%. Outside temperatures varied from 64° to 93°. (At the time of the lowest temperature, however, the humidity was 100%.) In the light of later findings, there is great significance in the fact that five of the players died on the first day of that season's practice and two died on the second day.
To investigate the uniform's responsibility for the heat load that players carry, Dr. Mathews set up a controlled experiment. His subjects were seven volunteers, all football players, of various heights and weights, five in their late teens and two in their 20s. The procedure followed was to test each under four different conditions, and in various orders. The first condition required the subject to put on, a scrub suit (a loose-fitting, well-ventilated cotton pajama) and run on a treadmill moving at six miles an hour for 20 minutes. As the subject ran, his temperature, heart rate, water loss, the amount of oxygen he used and the total amount of air he breathed were recorded minute by minute. Then, while the subject rested, the recordings were continued for 30 minutes more. Later the subject wore a complete football uniform, including the helmet, except for rib pads and football shoes (sneakers were substituted). Once again recordings were made of his physiological reactions as he ran at six miles an hour on the treadmill and as he later rested.
For the third condition the process was repeated, except that the subject, again wearing a scrub suit, ran at eight miles an hour for 20 minutes and rested for 30. Finally he performed in the same manner while wearing the football uniform.
Taking as the norm for each subject the reactions recorded while he ran wearing the scrub suit and comparing these reactions with those when the subject wore the uniform, the research team found that the uniform imposed a considerable burden. The subject's heart rate, rate of oxygen use and the total air intake shot up markedly. But even more dramatic were the rises in body temperature and the amount of water loss. When subjects ran the treadmill at eight miles an hour, their average rise in temperature was 33% higher when they wore uniforms than when they wore scrub suits. The average jump in water loss, by the same comparison, was 63%. In addition, the temperature of a subject wearing a scrub suit stayed level for a few minutes after he stopped exercising and then slowly dropped to normal—but the temperature of the same subject in a football uniform continued to rise after he stopped exercising. It dropped back to normal much more slowly. One of the team's conclusions was that the microclimate created inside the uniform prevents effective dissipation of heat. "Naturally," comments Dr. Ashe, "the longer the heat load must be carried, the more danger there is to the player."
To explore the heat-hoarding qualities of the uniform, Dr. Mathews sent one to the U.S. Army Research Institute of Environmental Medicine at Natick, Mass., where Dr. Ralph F. Goldman tested it on the so-called "copper man." This is actually a calorimeter (measurer of heat) in the shape of a human being. Patterned in size after an average taken of 5,000 Air Force cadets, the copper figure is 5 feet 8 inches tall and has the physique of a 175-pound man. It is heated electrically by a network of wires under its "skin" to the desired number of degrees, in the manner of an electric blanket.
Dressed in the uniform for these tests, the copper man's skin temperature was maintained at 92°, the average skin temperature of a man at rest. The room was kept between 40° and 50°. Twenty thermocouples—electrical devices for measuring temperatures at specific areas on a surface—were attached at various points on the copper man, some under the jersey, some under padded areas of the pants, some under the stockings and so on. Then various currents were turned on, and individual thermocouple readings were taken.
When the readings were translated into calories (units of heat), it was found that, while the nonpadded areas of the uniform allowed heat to dissipate, the padded areas did not. Says Dr. Goldman, "To maintain temperature at normal levels, the average player must produce and efficiently evaporate about 1‚Öî pounds of sweat an hour. It is well within a person's ability to produce this much sweat. Evaporating this much on a hot, humid day or through this uniform is another story. Inability to evaporate this sweat will, of course, result in increasing body temperatures. A 185-pound player will have a body temperature rise of 1° for each two to three ounces of sweat he is unable to eliminate. Thus, if the humidity is 100%, body temperatures could rise 10° or 11° in an hour, which is intolerable. Heat exhaustion, sheer physical exhaustion or, at worst, heatstroke would occur first. The uniform, with all the plastic or plasticized pads, obviously blocks evaporative heat transfer over 40% to 50% of the body surface." When adhesive tape is worn in addition to the uniform—on the ankles, wrists, thighs or ribs—the percentage of skin available to cool the body through evaporation of sweat is further lowered.
With the padding in the uniform thus identified as a major factor in heatstroke and heat exhaustion, two solutions to the problem suggested themselves to the OSU research team. The first was to see if it was possible to increase the ventilation of the pads. The second—regardless of the success of the first—was to devise a program of acclimatization for players so that they could develop resistance to great heat loads.
Preliminary inquiries by SPORTS ILLUSTRATED indicate that, at the moment at least, manufacturers are reluctant to add perforations to uniform padding, the most obvious way of allowing air to penetrate. Perforations, it is pointed out, inevitably weaken the material, reducing its protective qualities. It is a question of which presents the greater risk—injury to a limb, organ, joint or muscle or the less likely possibility of suffering heat exhaustion or heatstroke. Says Howard Wilkins of the Brunswick Sports Co., a prominent uniform (MacGregor) manufacturer, "The prime purpose of the padding is to protect the player from injury. We haven't been working on this part [the heat factor] of the problem. It has only come to my attention in the last year or so. But I think it can be accomplished without perforating the padding."
The padding is not the only problem. Because the head functions somewhat like a chimney flue in drawing heat upward and allowing it to dissipate, covering the head and part of the face with a helmet likewise interferes with the body's efforts to cast off heat. Some helmets have small holes at the top and some do not; most have shock-absorbent features that provide protection for the player's head. None of them, however, provides good ventilation. Further research by equipment manufacturers obviously is called for. In the meantime, Dr. Mathews recommends that players be allowed to remove their helmets when opportunities arise—in lulls during practice or time-outs during a scrimmage or a game.
Despite the attention they are now receiving, it is not likely that the pads or the helmet will be changed drastically in the near future. Dr. Mathews therefore advocates a program of acclimatization whereby a player can become "90% accustomed, after five or six days, to the heat load he must carry." During this period there should be about two hours' practice in the morning and two in the afternoon. On the first day players should wear shorts and tennis shoes. In morning and afternoon they should alternate 20 minutes of workout with 20 minutes of rest in the shade. On the second day, still in shorts and tennis shoes, they should work out for 23 minutes, then take 20 minutes of rest in the shade. On the morning of the third day, 26 minutes of workout in football uniform, 20 minutes of rest in the shade; in the afternoon, the same schedule of workout and rest, in shorts and tennis shoes. On the fourth day, morning and afternoon, 30 minutes of workout in uniform, 20 minutes of rest in the shade. On the fifth day, morning and afternoon, 50 minutes of workout in uniform, 15 minutes of rest in the shade. "The healthy human body readily adapts itself to withstanding heat stress," Dr. Mathews says, "but the adaptation must be gradual. If a team can't fit this program into existing schedules, it should start practice a week early."
Dr. Mathews also urges free use of water by players when they are thirsty. "It's an old wives' tale that athletes shouldn't be allowed to drink water while working out," he says. "Failure to replenish the water and salt lost while exercising is a basic cause of heat exhaustion and heatstroke. Players should be given water whenever they want and be allowed to drink as much as they want, provided they continue to take salt along with it."
Additional recommendations come from OSU Team Physician Dr. Robert J. Murphy: during the early part of the season players should wear a short-sleeved jersey and no stockings; in hot weather players should change into dry T shirt halfway through practice or a game; the weight of each player should be checked before and after practice to determine if water loss is excessive; vitamin C (found notably in oranges, lemons and tomatoes) should be taken regularly, since it seems to be useful in preventing heatstroke. Dr. Murphy also recommends that if the temperature goes to between 80° and 90°, with the humidity over 70%, players should be given a 10-minute rest period every hour and that the T shirt should be changed when soaked. When the temperature reaches between 90° and 100° and humidity is at 70%, practice should be postponed or sharply curtailed.
The Oklahoma program
Though the causative factors in heatstroke are just now being recognized, it has long been known that physiological changes brought about by overheating reduce any player's efficiency, even if they do not cause him physical injury. One of the most elaborate acclimatization programs to combat these ill effects is that of the University of Oklahoma, under the direction of Coach Bud Wilkinson and Trainer Ken Rawlinson. In August, three weeks before the start of football practice, a supply of salt tablets and ascorbic acid is sent to players to build up their salt levels at home. (Perspiration contains a slight amount of ascorbic acid—vitamin C—as well as salt.) They are also sent Wilkinson's recommendations on how to control their weight, along with conditioning and exercise drills. When practice starts, the U.S. Weather Bureau is called every night to determine the estimated temperature and relative humidity for the following morning. If there is afternoon as well as morning practice, the bureau is phoned again at 11 a.m. to determine the afternoon's weather. The length and intensity of practice sessions are determined by the figures reported.
Before and after each practice, players are given salt and ascorbic acid tablets. After half an hour of practice, players are given a seven-ounce cup of saline solution—about one tablespoon of salt to a gallon of water. At the end of the second half hour, players are given a 10-minute rest and seven-ounce cup of soft drink. At the end of the third half hour they receive another cup of saline solution. When the two-hour session is over, players are encouraged to drink as much saline solution, flavored with lemon, as they wish. They may also have one bottle of soft drink.
When Oklahoma was about to play USC last September 28 in what was expected to be a scorching temperature, the salt intake of Oklahoma players was increased. At the Saturday pregame meal, each player was told to take several tablets, and salt was available in the dressing room before and after the game. USC authorities, also worried about the heat, hospitably furnished both benches with bamboo shades, which were sprinkled with water before the game and during the half. A five-gallon can filled with saline solution stood by the Oklahoma bench. It was emptied five times during the course of the game. At half time Oklahoma players were served a soft drink. During time-outs, Oklahoma players on the field washed out their mouths with a refreshing peppermint solution that was squirted from a pressure can. Player substitutions on both teams were frequent, to prevent anyone from getting overtired, and players were watched closely by the coaches for any sign of heat exhaustion or heatstroke. The referee was instructed to take additional official time-outs if any player on either team looked woozy.
USC combatted the heat in the days before the game by changing its practice hours from afternoons to the evening and practicing only half as long as usual. Players were given extra salt tablets, and even during practice substitutions were frequent. The team's diet leaned heavily on salads and light foods.
All these preparations and precautions paid off. With the temperature 105° in the shade and a murderous 120° on the field, no player on either team showed a single symptom of heat exhaustion or heatstroke.
With their work nearing its conclusion, one member of Dr. Mathews' team recently commented, "A kid goes out to die for dear old Siwash, and he winds up doing just that." Oklahoma and USC—and Dr. Mathews' team of researchers—have shown that so far as heatstroke is concerned, dying for dear old Siwash can be purely figurative from now on.