NEW YORK (Reuters Health)
— Using cold water, ice
baths or ice vests before or during a workout in the heat helps
athletes perform better, according to a new review.
One way to think about it, said study author Dr.
Thijs M H Eijsvogels, would be that cooling techniques may reduce
the amount of energy the body needs to use to stay cool, leaving
more energy for the exercise itself.
"More blood will be available for oxygen transportation to the
exercising muscles, which enables a better performance," he told
Reuters Health by email. "Thus less energy and effort is spilled for
heat dissipating mechanisms."
Eijsvogels, of the physiology department at Radboud University
Medical Center in The Netherlands, and his colleagues included 28
studies in their review of prior research on cooling techniques.
All the studies focused on methods used by male athletes when
temperatures were above 86 degrees Fahrenheit, and 20 of those
looked at "precooling" techniques used before the workout began.
Before exercise, the athletes used methods like wearing a cooling
vest or cooling packs, immersing themselves in cold water, drinking
cold water or an ice slurry, or a combination of these.
During exercise, the methods were the same with the exception of
dunking in a cold pool.
Overall, using cooling techniques before or during exercise improved
performance and combining the two worked best, according to the
results published in the British Journal of Sports Medicine.
The most effective methods were the ice vest during exercise and a
combination of all the techniques before exercise.
On average, athletes who used cooling techniques performed almost
seven percent better than those who did not, which could mean the
difference between winning and losing, Eijsvogels said.
"Remember that in many elite sports the difference between a first
and fourth place is marginal, so improving your performance with 6.7
percent due to the application of appropriate cooling techniques can
have a large impact on the race result," he said.
Even average athletes would notice a difference, said Dr. Paul
Laursen, physiology manager at High Performance Sport New Zealand in
"If performance matters to you, then it's worth the effort," Laursen
told Reuters Health by email. He was not involved in the review.
The authors caution that most of the studies they analyzed were
very small, including an average of nine people, and there may have
been other studies finding less of an effect or no effect that were
not published, which would skew their result.
Exercise increases core temperature, which can hurt performance. The
review found that precooling decreased peak core body temperatures
from 102.4 degrees Fahrenheit to 100.6 degrees.
"In general, the exercise-induced increase in core body
temperature could lead to the development of heat-related illnesses,
such as heat stroke," Eijsvogels said. Cooling strategies may
potentially do more than just improve performance, they may also
reduce the risk of heat-related illnesses, he said.
Currently only some elite athletes use cooling techniques, mostly
for sports like racing, cycling, motor cross racing, soccer and
field hockey, he said. Ice vests are heavy to wear during a workout,
and most casual exercisers don't have access to ice slurry during a
race, he said.
But he advocates wider use of the techniques beyond elite athletes,
and novel developments in cooling fabric and gadgets might change
this in the near future, he said.
"The take-home message is that you want to know what you're doing
beforehand — test things out first that make sense based on the
science, and once you're confident that these will work for you,
have a go in real competition," Laursen said.