The reasons are also no surprise. Blood is directed to the skin for cooling, which means it is diverted from working muscles. The hotter it is, and the harder the effort, the harder exercise becomes. Eventually, you slow down or stop, unable to go on. Exercise physiologists debate why. It could be that muscles are starved for blood. It could be that the brain gets too hot. It could be that the heart eventually can’t beat fast enough to satisfy all the demands for blood. But even without knowing why, researchers have found they can delay the time to utter exhaustion by getting people a bit chilled before they start.
So companies sell devices, like cooling vests to wear before exercise, or even portable cold baths for prerace immersion. Researchers have tested methods like having athletes swim for an hour in cold water or sit in a cold room or stand in a cold shower. No matter what the method, companies and researchers report a precooling effect.
The problem is that none of the methods are easy, cheap and practical. But now, a New Zealand endurance athlete and exercise researcher says he has found a method that is. All you have to do is drink an ice slurry, also known as a slushie, before exercising. In a new study, he reports that young male recreational athletes who drank a syrup-flavored ice slurry just before running on a treadmill in hot room could keep going for an average of 50 minutes before they had to stop. When they drank only syrup-flavored cold water, they could run for an average of 40 minutes.
There are limitations — the running test was indoors, so there was no cooling effect from breezes on the skin. In those artificial circumstances, precooling might have had more dramatic effects than it would outdoors. And what athletes really want is to go faster in a race, not run until they drop. But the study tested endurance, not performance, which is typical of such research.
Still, exercise specialists say, the effect was pronounced. “It’s a really interesting study, well done and carefully thought out,” said Craig Crandell, an exercise physiologist at the University of Texas Southwestern Medical Center, who studies the effects of exercising in the heat.
The effect was short-lived, according to the senior investigator, Paul Laursen, at the New Zealand Academy of Sport in Auckland and a competitor who has raced in 13 Ironman triathlons (a 2.4-mile swim followed by a 112-mile bike race followed by a marathon-distance 26.2-mile run). It would not even begin to last long enough to run a marathon or do a century (100-mile) bike ride, for example. But it would be perfect for a sport like tennis or for a 5- or 10-kilometer race or for team sports like soccer or football, and it might give endurance athletes in longer events a boost by letting them beat the heat, to a certain extent, for the first 50 minutes or so.
Dr. Laursen said he thought of using ice slurries because they can lower brain temperature in swine more effectively than cold water. The swine studies were testing methods to cool the body before surgery. Dr. Laursen reasoned that slurries might also effectively cool the body before exercise. The advantage, he said, is that they are even colder than ice — 30 degrees Fahrenheit — an effect that occurs when sugary water is swirled with crushed ice.
“It’s a neat idea,” said Scott Montain, an exercise researcher at the United States Army Research Institute of Environmental Medicine in Natick, Mass. “I wouldn’t have guessed slurries would have that much of an effect.”
It’s not so clear why ice slurries or any other method work, though. As Dr. Laursen notes in a review article, “The mechanisms underlying the performance effects associated with precooling are not yet completely understood.” One possibility, which Dr. Laursen said might have explained the ice slurry results, was that slurries lowered body temperature before the young men ran, letting them run for a longer time before their bodies became critically hot.
Dr. Montain is not sure. The men did not get that hot, he said. At exhaustion, the mean body temperature of those who drank the slurry and those who drank cold water was about 101 degrees.
He said the limiting factor might have been the men’s heart rates. In both groups, exhaustion occurred when heart rates reached about 185 beats per minute. Those who drank the slurry hit that heart rate 10 minutes later than those who drank cold water. Dr. Montain says the heart beats faster and faster, trying to get blood to the skin, for cooling, and to the muscles for exercising, until it just can’t keep up.
“The heart can’t send blood everywhere without the blood pressure falling,” Dr. Montain said. “At some point, you can’t maintain your blood pressure.” But, Dr. Montain said, what mattered in the end was that the simple solution of drinking an ice slurry worked. He might even try drinking a one himself if he’s stuck racing in the heat, something he tries to avoid.
癌症肺癌肺癌症状肺癌的症状肺癌治疗肺癌的治疗方法肺癌的早期症状肺癌晚期症状胃癌胃癌的治疗胃癌的治疗方法胃癌症状胃癌的症状胃癌的早期症状胃癌的临床表现肝癌肝癌症状肝癌的症状肝癌的治疗肝癌治疗方法肝癌早期症状肝癌晚期症状肝癌患者的饮食肝癌的临床表现肾癌肾癌症状肾癌的症状肾癌治疗肾癌的治疗方法食道癌食道癌症状食道癌的症状食道癌的治疗食道癌的治疗方法食道癌的早期症状子宫颈癌宫颈癌子宫颈癌的症状宫颈癌症状宫颈癌的治疗宫颈癌的治疗方法子宫颈癌的治疗方法宫颈癌早期症状乳腺癌乳腺癌症状乳腺癌的症状乳腺癌的治疗乳腺癌的治疗方法乳腺癌晚期能活多久乳腺癌的治疗费用乳腺癌晚期得了乳腺癌怎么办乳腺癌早期症状乳腺癌的前期症状乳腺癌的晚期症状乳腺癌的晚期治疗卵巢癌卵巢癌症状卵巢癌的症状卵巢癌的治疗卵巢癌的治疗方法卵巢癌的早期症状卵巢癌早期症状卵巢癌的晚期症状直肠癌直肠癌症状直肠癌的症状直肠癌的治疗直肠癌的治疗方法直肠癌的早期症状直肠癌的晚期症状直肠癌的临床症状直肠癌的临床表现结肠癌结肠癌症状结肠癌的症状结肠癌治疗结肠癌的治疗方法结肠癌的临床症状皮肤癌皮肤癌症状皮肤癌的症状皮肤癌的治疗皮肤癌的治疗方法甲状腺癌甲状腺癌症状甲状腺癌的症状甲状腺癌治疗甲状腺癌的治疗方法胰腺癌胰腺癌症状胰腺癌的症状胰腺癌的治疗胰腺癌的治疗方法前列腺癌前列腺癌症状前列腺癌的症状前列腺癌的治疗前列腺癌的治疗方法前列腺癌的晚期症状膀胱癌膀胱癌症状膀胱癌的症状膀胱癌的治疗膀胱癌的治疗方法骨癌骨癌症状骨癌的症状骨癌治疗骨癌的治疗方法骨癌的早期症状鼻咽癌鼻咽癌症状鼻咽癌的症状鼻咽癌的治疗鼻咽癌的治疗方法脑瘤脑瘤症状脑瘤的症状脑瘤的治疗脑瘤的治疗方法肿瘤肺癌胃癌肝癌食道癌贲门癌直肠癌结肠癌宫颈癌卵巢癌乳腺癌子宫癌胰腺癌甲状腺癌胆囊癌胆管癌肾癌膀胱癌子宫肌瘤胃癌食管癌皮肤癌肺癌乳腺癌胆管癌肝癌宫颈癌胆囊癌肾癌胰腺癌甲状腺癌脑瘤直肠癌前列腺癌舌癌结肠癌膀胱肿瘤喉癌淋巴瘤睾丸肿瘤鼻咽癌白血病胃癌的治疗食管癌的治疗皮肤癌的治疗肺癌的治疗乳腺癌的治疗胆管癌的治疗肝癌的治疗宫颈癌的治疗胆囊癌的治疗肾癌的治疗胰腺癌的治疗甲状腺癌的治疗脑瘤的治疗直肠癌的治疗前列腺癌的治疗舌癌的治疗结肠癌的治疗膀胱肿瘤的治疗喉癌的治疗淋巴瘤的治疗睾丸肿瘤的治疗鼻咽癌的治疗白血病的治疗胃癌症状食管癌症状皮肤癌症状肺癌症状乳腺癌症状胆管癌症状肝癌症状宫颈癌症状胆囊癌症状肾癌症状胰腺癌症状甲状腺癌症状脑瘤症状直肠癌症状前列腺癌症状舌癌症状结肠癌症状膀胱肿瘤症状喉癌症状淋巴瘤症状睾丸肿瘤鼻咽癌症状白血病症状 “I try to race when the weather is good,” Dr. Montain said. “I live in Massachusetts, so I can choose.”
Dr. Crandall, in Dallas, might seem the ideal person to use a slurry before a run. But he’s less interested.
“I just run for enjoyment,” he said. And if he drank a slurry with its sugary syrup, he said, “all the calories I burned off would be added back.” Dr. Laursen, though, is drinking slurries. He gets ice cream headaches when he drinks them — everyone does, he said — but he puts up with the pain. It’s worth it.
When he has a slurry before a grueling bout of exercise in the heat, he said, “I feel so much better.”
So companies sell devices, like cooling vests to wear before exercise, or even portable cold baths for prerace immersion. Researchers have tested methods like having athletes swim for an hour in cold water or sit in a cold room or stand in a cold shower. No matter what the method, companies and researchers report a precooling effect.
The problem is that none of the methods are easy, cheap and practical. But now, a New Zealand endurance athlete and exercise researcher says he has found a method that is. All you have to do is drink an ice slurry, also known as a slushie, before exercising. In a new study, he reports that young male recreational athletes who drank a syrup-flavored ice slurry just before running on a treadmill in hot room could keep going for an average of 50 minutes before they had to stop. When they drank only syrup-flavored cold water, they could run for an average of 40 minutes.
There are limitations — the running test was indoors, so there was no cooling effect from breezes on the skin. In those artificial circumstances, precooling might have had more dramatic effects than it would outdoors. And what athletes really want is to go faster in a race, not run until they drop. But the study tested endurance, not performance, which is typical of such research.
Still, exercise specialists say, the effect was pronounced. “It’s a really interesting study, well done and carefully thought out,” said Craig Crandell, an exercise physiologist at the University of Texas Southwestern Medical Center, who studies the effects of exercising in the heat.
The effect was short-lived, according to the senior investigator, Paul Laursen, at the New Zealand Academy of Sport in Auckland and a competitor who has raced in 13 Ironman triathlons (a 2.4-mile swim followed by a 112-mile bike race followed by a marathon-distance 26.2-mile run). It would not even begin to last long enough to run a marathon or do a century (100-mile) bike ride, for example. But it would be perfect for a sport like tennis or for a 5- or 10-kilometer race or for team sports like soccer or football, and it might give endurance athletes in longer events a boost by letting them beat the heat, to a certain extent, for the first 50 minutes or so.
Dr. Laursen said he thought of using ice slurries because they can lower brain temperature in swine more effectively than cold water. The swine studies were testing methods to cool the body before surgery. Dr. Laursen reasoned that slurries might also effectively cool the body before exercise. The advantage, he said, is that they are even colder than ice — 30 degrees Fahrenheit — an effect that occurs when sugary water is swirled with crushed ice.
“It’s a neat idea,” said Scott Montain, an exercise researcher at the United States Army Research Institute of Environmental Medicine in Natick, Mass. “I wouldn’t have guessed slurries would have that much of an effect.”
It’s not so clear why ice slurries or any other method work, though. As Dr. Laursen notes in a review article, “The mechanisms underlying the performance effects associated with precooling are not yet completely understood.” One possibility, which Dr. Laursen said might have explained the ice slurry results, was that slurries lowered body temperature before the young men ran, letting them run for a longer time before their bodies became critically hot.
Dr. Montain is not sure. The men did not get that hot, he said. At exhaustion, the mean body temperature of those who drank the slurry and those who drank cold water was about 101 degrees.
He said the limiting factor might have been the men’s heart rates. In both groups, exhaustion occurred when heart rates reached about 185 beats per minute. Those who drank the slurry hit that heart rate 10 minutes later than those who drank cold water. Dr. Montain says the heart beats faster and faster, trying to get blood to the skin, for cooling, and to the muscles for exercising, until it just can’t keep up.
“The heart can’t send blood everywhere without the blood pressure falling,” Dr. Montain said. “At some point, you can’t maintain your blood pressure.” But, Dr. Montain said, what mattered in the end was that the simple solution of drinking an ice slurry worked. He might even try drinking a one himself if he’s stuck racing in the heat, something he tries to avoid.
癌症肺癌肺癌症状肺癌的症状肺癌治疗肺癌的治疗方法肺癌的早期症状肺癌晚期症状胃癌胃癌的治疗胃癌的治疗方法胃癌症状胃癌的症状胃癌的早期症状胃癌的临床表现肝癌肝癌症状肝癌的症状肝癌的治疗肝癌治疗方法肝癌早期症状肝癌晚期症状肝癌患者的饮食肝癌的临床表现肾癌肾癌症状肾癌的症状肾癌治疗肾癌的治疗方法食道癌食道癌症状食道癌的症状食道癌的治疗食道癌的治疗方法食道癌的早期症状子宫颈癌宫颈癌子宫颈癌的症状宫颈癌症状宫颈癌的治疗宫颈癌的治疗方法子宫颈癌的治疗方法宫颈癌早期症状乳腺癌乳腺癌症状乳腺癌的症状乳腺癌的治疗乳腺癌的治疗方法乳腺癌晚期能活多久乳腺癌的治疗费用乳腺癌晚期得了乳腺癌怎么办乳腺癌早期症状乳腺癌的前期症状乳腺癌的晚期症状乳腺癌的晚期治疗卵巢癌卵巢癌症状卵巢癌的症状卵巢癌的治疗卵巢癌的治疗方法卵巢癌的早期症状卵巢癌早期症状卵巢癌的晚期症状直肠癌直肠癌症状直肠癌的症状直肠癌的治疗直肠癌的治疗方法直肠癌的早期症状直肠癌的晚期症状直肠癌的临床症状直肠癌的临床表现结肠癌结肠癌症状结肠癌的症状结肠癌治疗结肠癌的治疗方法结肠癌的临床症状皮肤癌皮肤癌症状皮肤癌的症状皮肤癌的治疗皮肤癌的治疗方法甲状腺癌甲状腺癌症状甲状腺癌的症状甲状腺癌治疗甲状腺癌的治疗方法胰腺癌胰腺癌症状胰腺癌的症状胰腺癌的治疗胰腺癌的治疗方法前列腺癌前列腺癌症状前列腺癌的症状前列腺癌的治疗前列腺癌的治疗方法前列腺癌的晚期症状膀胱癌膀胱癌症状膀胱癌的症状膀胱癌的治疗膀胱癌的治疗方法骨癌骨癌症状骨癌的症状骨癌治疗骨癌的治疗方法骨癌的早期症状鼻咽癌鼻咽癌症状鼻咽癌的症状鼻咽癌的治疗鼻咽癌的治疗方法脑瘤脑瘤症状脑瘤的症状脑瘤的治疗脑瘤的治疗方法肿瘤肺癌胃癌肝癌食道癌贲门癌直肠癌结肠癌宫颈癌卵巢癌乳腺癌子宫癌胰腺癌甲状腺癌胆囊癌胆管癌肾癌膀胱癌子宫肌瘤胃癌食管癌皮肤癌肺癌乳腺癌胆管癌肝癌宫颈癌胆囊癌肾癌胰腺癌甲状腺癌脑瘤直肠癌前列腺癌舌癌结肠癌膀胱肿瘤喉癌淋巴瘤睾丸肿瘤鼻咽癌白血病胃癌的治疗食管癌的治疗皮肤癌的治疗肺癌的治疗乳腺癌的治疗胆管癌的治疗肝癌的治疗宫颈癌的治疗胆囊癌的治疗肾癌的治疗胰腺癌的治疗甲状腺癌的治疗脑瘤的治疗直肠癌的治疗前列腺癌的治疗舌癌的治疗结肠癌的治疗膀胱肿瘤的治疗喉癌的治疗淋巴瘤的治疗睾丸肿瘤的治疗鼻咽癌的治疗白血病的治疗胃癌症状食管癌症状皮肤癌症状肺癌症状乳腺癌症状胆管癌症状肝癌症状宫颈癌症状胆囊癌症状肾癌症状胰腺癌症状甲状腺癌症状脑瘤症状直肠癌症状前列腺癌症状舌癌症状结肠癌症状膀胱肿瘤症状喉癌症状淋巴瘤症状睾丸肿瘤鼻咽癌症状白血病症状 “I try to race when the weather is good,” Dr. Montain said. “I live in Massachusetts, so I can choose.”
Dr. Crandall, in Dallas, might seem the ideal person to use a slurry before a run. But he’s less interested.
“I just run for enjoyment,” he said. And if he drank a slurry with its sugary syrup, he said, “all the calories I burned off would be added back.” Dr. Laursen, though, is drinking slurries. He gets ice cream headaches when he drinks them — everyone does, he said — but he puts up with the pain. It’s worth it.
When he has a slurry before a grueling bout of exercise in the heat, he said, “I feel so much better.”
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