Topic for Jun.2 ( Fri )

[suyun**]

Boost Your Workouts With Caffeine, Even if You Chug Coffee Daily

Credit Tony Cenicola/The New York Times

Caffeine improves athletic performance. This is a truth almost universally acknowledged in exercise science.

But scientists, coaches and athletes also have thought that to gain any performance boost from taking caffeine before an event, an athlete had to abstain from the stuff for days or weeks before a big event.

A new study published in the Journal of Applied Physiology intimates, however, that these ideas about caffeine and performance are out of date and that someone can swill coffee every day and still get a caffeine performance buzz when needed.

Caffeine is, of course, one of the world’s most popular mind-altering substances, used by millions of us to jump-start our sluggish morning brain function and goose alertness throughout the day.

Taken an hour or so before exercise, it also enables most athletes to run, bike, swim or otherwise perform a little faster or more vigorously than if they do not have caffeine first.

Caffeine provides this boost by making it easier for muscles to burn body fat, of which we all have ample supplies. It also increases alertness, which seems to make exercise feel less strenuous. (Caffeine is not banned from sports except in very high doses.)

But caffeine users tend to become habituated to its effects, as those of us who have watched our morning consumption creep up by a cup or three can attest.

So athletes typically have been advised to quit drinking coffee or anything else that contains caffeine for most of the week before a major competition, on the theory that doing so should reduce their habituation and amplify the impacts of caffeine on the day of the event.

But Bruno Gualano, a professor of physiology and nutrition at the University of São Paulo in Brazil, was unconvinced. A recreational cyclist and committed coffee drinker — “as a good Brazilian, coffee is part of my diet,” he says — he thought it possible that athletes could benefit from taking caffeine before an event, even if they had not abstained in the days beforehand.

To test that idea, he and his colleagues first recruited 40 competitive male cyclists from São Paulo and invited them to the university’s human performance lab for a series of health and performance tests.

They also questioned the riders extensively about their normal intake of caffeine. How many cups of coffee, tea, cola, Red Bull and so on did they drink every day or week?

Based on that information, the researchers stratified the riders into a low-caffeine group, which averaged about a cup or less of coffee or other caffeinated drinks on most days; a moderate-caffeine group, which downed the equivalent of about two cups of coffee on most days; and a high-caffeine group, which drank about three cups of coffee or more on most days.

These riders then reported to the lab three more times. At each visit, they completed a specialized type of time trial, during which they rode as hard as possible until they had burned through about 450 calories, a task designed to take these riders about 30 minutes.

(They were asked not to eat or drink anything in the morning before reporting to the lab.)An hour before one ride, they swallowed a tablet that contained about 400 milligrams of caffeine, an amount equivalent to about four cups of regular coffee.

An hour before another, they received an identical-looking tablet that contained only gelatin as a placebo. The riders were not told what was in the tablets.They did not receive any tablets before their final ride.Afterward, the researchers compared their times.

Almost all of the riders had pedaled hardest and fastest after swallowing the caffeine pill, completing their ride 3.3 percent faster on average compared to when they had had no pill and 2.2 percent faster than after they had swallowed the placebo. For comparison, a 2 to 3 percent gain in performance could shave several minutes from a recreational runner’s marathon race time.

An hour before one ride, they swallowed a tablet that contained about 400 milligrams of caffeine, an amount equivalent to about four cups of regular coffee.

An hour before another, they received an identical-looking tablet that contained only gelatin as a placebo. The riders were not told what was in the tablets.

They did not receive any tablets before their final ride.

Afterward, the researchers compared their times.

Almost all of the riders had pedaled hardest and fastest after swallowing the caffeine pill, completing their ride 3.3 percent faster on average compared to when they had had no pill and 2.2 percent faster than after they had swallowed the placebo.

 For comparison, a 2 to 3 percent gain in performance could shave several minutes from a recreational runner’s marathon race time.

Most interesting, the results were the same whether the riders normally were light, moderate or heavy caffeine users.

The cyclists who usually chugged large amounts of coffee or other caffeine drinks every day received the same boost from caffeine as light coffee drinkers, even though they had not abstained from caffeine for days beforehand.

“No matter the habitual caffeine intake in the diet, acute caffeine supplementation can improve performance,” Dr. Gualano says.

This finding could be helpful to athletes who might welcome a performance boost from caffeine but not at the cost of eschewing coffee for days beforehand, he says.

But there are significant caveats. This study involved fit young men. Whether women and those of us in less enviable physical condition will respond similarly to caffeine before exercise must still be studied, Dr. Gualano says.

Large doses of caffeine also can have undesirable and even dangerous side effects, including jitters, headaches, heart palpitations and stomach upset, even for people who are regular caffeine users.

If you wish to use caffeine to better your physical performance, Dr. Gualano says, start with small doses. A single cup of coffee an hour before exercise may be enough to ease and improve your subsequent workout.

 

 

 

 

 

 

 

 

[Joel Song]

Wow the letters are too small and fine to read.
I wish I had the source~

[hornet]

https://www.nytimes.com/2017/05/31/well/move/boost-your-workouts-with-caffeine-even-if-you-chug-coffee-daily.html?_r=0