|
 In particular, caffeine could help speed, power, strength and
endurance, researchers wrote in the British Journal of Sports
Medicine.
"Supplementation with caffeine is highly prevalent among athletes,
with one study from 2011 indicating that around 75 percent of urine
samples from athletes competing in the Olympic Games contain
measurable levels of caffeine," said lead author Jozo Grgic of
Victoria University in Melbourne, Australia.
In 2004, caffeine was removed from the World Anti-Doping Agency list
of substances banned during competitions.
"Since then, the intake of caffeine among athletes has only
increased with no signs of slowing down," Grgic told Reuters Health
by email.
Grgic and colleagues conducted an "umbrella review" - meaning they
looked at results of earlier reviews that analyzed multiple studies
of caffeine and exercise performance.
The 21 earlier reviews, done between 2004 and 2018, analyzed an
average of 19 studies each.
Grgic's team found that caffeine helped muscle endurance, muscle
strength, jumping performance, exercise speed, anaerobic power and
aerobic endurance.
Three reviews, involving an average of 13 studies each, supported
the ergogenic, or enhancing, effect of caffeine on strength. Two
reviews, which looked at a total of 39 studies, supported an effect
on endurance.
One review supported an effect of caffeine on vertical jump height,
and one supported speed during running, cycling and rowing.
In general, the effect of caffeine was greater for aerobic exercise
than for anaerobic exercise.
The "optimal" dose remains elusive, Grgic said. Although coffee is
the most widely-used form of caffeine globally, it's not commonly
studied as a pre-exercise performance enhancer. The caffeine dose
depends on coffee bean type, preparation method, cup size, brand and
additive flavors.
"As a broad rule of thumb, two cups of coffee, consumed around 60
minutes before exercise, should exert an ergogenic effect in most
individuals," Grgic said.
[to top of second column] |
But "the response to caffeine ingestion varies from person to
person," Grgic cautioned. "Individuals interested in supplementing
with caffeine should be careful with the dose of caffeine, as high
doses may result in strong side-effects such as a headache, nausea,
insomnia, and others."
One limitation of umbrella reviews is that they rely on the earlier
teams of researchers to accurately compare different measurements,
intervals, timeframes and study groups. In addition, most of the
studies involved young men. Future studies should be conducted among
more varied populations, Grgic said.
"Athletes are always looking for competitive advantage, investing
countless hours of training in their devotion towards improvement.
They build their bodies, perfect their techniques, and fine-tune all
their training and racing strategies, but do they know that the big
performance boost they're hoping for may simply come from their
pantry?" said Joy Shen, a registered dietician and sports
nutritionist in Boston.
Shen, who wasn't involved with this study, has worked with Harvard
University and Northeastern University researchers to study caffeine
and endurance.
"As with any pre-race strategy, test out caffeine in training before
the competition," she told Reuters Health by email. "Become a
scientist in your sport, studying yourself, because in competition,
you're the only athlete that matters."
SOURCE: http://bit.ly/2FZMt6v British Journal of Sports Medicine,
online March 29, 2019.
[© 2019 Thomson Reuters. All rights
reserved.] Copyright 2019 Reuters. All rights reserved. This material may not be published,
broadcast, rewritten or redistributed.
Thompson Reuters is solely responsible for this content.
 |
