Featured Research

from universities, journals, and other organizations

Does That "Java-Jolt" Affect Coffee And Non-Coffee Drinkers Alike?

Date:
July 16, 2002
Source:
American Physiological Society
Summary:
A new study finds that sustained coffee drinking does not increase physical productivity; non-users receive greater benefit boosts than do those who regularly indulge.

Bethesda, MD (July 15, 2002) -- The late author Anne Morrow Lindberg observed, "Good communication is as stimulating as black coffee, and just as hard to sleep after." While the art of conversation may have had its down periods, coffee has remained a renowned stimulant since its first appearance, circa 1,000 A.D.

Background

The first recorded users of coffee are the Galla tribe in Ethiopia who noticed that they received an energy boost when they ground up the coffee bean and mixed it with animal fat. One thousand years later, many in the tribe known as the American labor force swear that a strong cup of coffee erases the effects of too little sleep. Witness, for example, the fact that the thousands of Americans who protect our country rely on coffee for the stimulation to fly an aircraft, stand a watch at sea, or stay awake for long hours while planning combat operations.

Americans having their morning coffee refer to the caffeine effect as a "charge" or "jolt." Physiologists, the scientists who study what makes the body "tick," call that effect "ergogenic." But are those caffeine drinkers in military uniform, white collar shirts, blue collar overalls and no-collar t-shirts, correct in thinking that coffee consumption will assist them in "making it through the day?"

Numerous studies have already demonstrated that caffeine ingested before physical activity causes rapid and significant improvement in performance, especially in aerobic exercise capacity. Most researchers believe that caffeine's ergogenic effect is related to the circulating level of the drug in the bloodstream, creating an assumption that the maximum effects are found one hour after consumption.

Two physiologists, affiliated with the Canadian research and defense establishment, recently set out to clarify several issues: whether the ergogenic effect achieved following the ingestion of 5 mg.kg-1 is related to the circulating concentration of caffeine; the duration of the ergogenic effect following the ingestion of a 5 mg.kg-1 dose of caffeine; and whether these effects are different for users and non-users of caffeine.

The authors of "Exercise Endurance 1, 3, and 6 Hours After Caffeine Ingestion in Caffeine Users and Non-users," are Douglas G. Bell and Tom M. McLellan, both from the Operation Medicine Section, Defence R&D Canada, Toronto, Ontario, Canada. Their findings appeared in the Journal of Applied Physiology, articles in press, a journal of the American Physiological Society (APS).

Methodology

Nineteen civilian and two military subjects (15 males and six females) with a mean age of 32 +/- 7 years, height 179 +/- 9.5 cm, and body mass 74.8 +/- 12.6 kg participated in the study. All subjects were active in aerobic events, 13 were regular caffeine users (ingesting greater than or equal to 00 mg/day) and eight were considered non-users (ingesting less than or equal to 50 mg/day).

Caffeine was primarily ingested in the form of coffee. Subjects were asked to refrain from heavy exercise and alcohol for 24 hours before each trial. Caffeine consumption was halted 12 hours before the events.

The subjects completed six randomized exercise rides to exhaustion at 80 percent of maximal oxygen consumption on a cycle ergometer after ingesting either a placebo or 5 mg/kg of caffeine. Exercise to exhaustion was completed once per week at either one three, three or six hours after placebo or drug ingestion. Blood samples were taken from each subject.

Results

Key findings of the study were that:

* For all subjects, caffeine improved the time to exhaustion from 24.0 +/- 6.5 minutes during the placebo trials to 28.8 +/- 8.6 minutes. Improvement was found to be greater in the non-users of caffeine.

* The effect of caffeine was still found in non-users six hours after ingestion but not in the users.

* Heart rates were higher for non-users throughout the trials. The values increased over time and were further increased following caffeine consumption.

* Caffeine produced a small but significant increase in oxygen consumption after 15 minutes of exercise for users and non-users.

* Non-users had higher glucose levels prior to exercise. Caffeine consumption elevated the levels at a slight but significant rate.

* The change of caffeine concentration in plasma above the baseline value was the same for users and non-users following caffeine intake. For the one-hour trial, however, caffeine concentration increased significantly throughout exercise, whereas it remained constant in trials conducted at three and six hours after ingestion. Generally, the concentration increased one and three hours after caffeine intake was greater than that after six hours.

Conclusions

Non-users demonstrated a greater ergogenic benefit or "boost" from caffeine consumption than regular users. Regular users may benefit from that first cup of coffee but non-users can derive additional energy. But neither group is aided by too many trips to the coffee pot.

###

The American Physiological Society (APS) was founded in 1887 to foster basic and applied science, much of it relating to human health. The Bethesda, MD-based Society has more than 10,000 members and publishes 3,800 articles in its 14 peer-reviewed journals every year.


Story Source:

The above story is based on materials provided by American Physiological Society. Note: Materials may be edited for content and length.


Cite This Page:

American Physiological Society. "Does That "Java-Jolt" Affect Coffee And Non-Coffee Drinkers Alike?." ScienceDaily. ScienceDaily, 16 July 2002. <www.sciencedaily.com/releases/2002/07/020716075936.htm>.
American Physiological Society. (2002, July 16). Does That "Java-Jolt" Affect Coffee And Non-Coffee Drinkers Alike?. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2002/07/020716075936.htm
American Physiological Society. "Does That "Java-Jolt" Affect Coffee And Non-Coffee Drinkers Alike?." ScienceDaily. www.sciencedaily.com/releases/2002/07/020716075936.htm (accessed July 30, 2014).

Share This




More Health & Medicine News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Concern Grows Over Worsening Ebola Crisis

Concern Grows Over Worsening Ebola Crisis

AFP (July 30, 2014) Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone amid the worsening Ebola health crisis, which has so far caused 672 deaths in Guinea, Liberia and Sierra Leone. Duration: 00:43 Video provided by AFP
Powered by NewsLook.com
Generics Eat Into Pfizer's Sales

Generics Eat Into Pfizer's Sales

Reuters - Business Video Online (July 29, 2014) Pfizer, the world's largest drug maker, cut full-year revenue forecasts because generics could cut into sales of its anti-arthritis drug, Celebrex. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Nigeria Ups Ebola Stakes on 1st Death

Nigeria Ups Ebola Stakes on 1st Death

Reuters - Business Video Online (July 29, 2014) Nigerian authorities have shut and quarantined a Lagos hospital where a Liberian man died of the Ebola virus, the first recorded case of the highly-infectious disease in Africa's most populous economy. David Pollard reports Video provided by Reuters
Powered by NewsLook.com
Running 5 Minutes A Day Might Add Years To Your Life

Running 5 Minutes A Day Might Add Years To Your Life

Newsy (July 29, 2014) According to a new study, just five minutes of running or jogging a day could add years to your life. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins