Science

We've done a lot of research so that we can bring you a selection of credible evidence for the health benefits of coffee and the benefits caffeine can have as a sports supplement.


THE HEALTH BENEFITS OF COFFEE

Coffee, Caffeine, and Health Outcomes: An Umbrella Review
Guiseppe Grosso, Justyna Godos, Fabio Glavano and Edward Giovannucci
Annual Review of Nutrition 2017

https://www.annualreviews.org/doi/full/10.1146/annurev-nutr-071816-064941#_i2

This systematic review looked at 112 observational studies and found coffee was associated with a probable decreased risk of several types of cancer, cardiovascular disease, Parkinson’s disease and Type-2 Diabetes.  

Coffee consumption and reduced risk of developing type 2 diabetes: a systematic review with meta-analysis
Mattias Carlström,  Susanna C Larsson
Nutrition Reviews, Volume 76, Issue 6, 1 June 2018, Pages 395–417

https://academic.oup.com/nutritionreviews/article-abstract/76/6/395/4954186

This review found the risk of Type2 Diabetes decreased by 6% (RR = 0.94; 95%CI, 0.93–0.95) for each cup-per-day increase in coffee consumption (up to 5). Available evidence indicates that coffee consumption is inversely associated with risk of T2D.

Scientists wake up to coffee’s benefits

BMJ 2017; 359 doi: https://doi.org/10.1136/bmj.j5381 (Published 22 November 2017) 
https://www.bmj.com/content/359/bmj.j5381

This wide ranging study found drinking three cups of coffee a day to be associated with reduced risk of cardiovascular disease, coronary heart disease, and stroke, when compared with not drinking coffee. Consumption at this level was associated with a 19% lower risk of mortality from cardiovascular disease (relative risk 0.81, 95% confidence interval 0.72 to 0.90), a 16% lower risk of mortality from coronary heart disease (relative risk 0.84, 0.71 to 0.99), and a 30% lower risk of stroke mortality.

There are many news stories regarding this study but a useful synopsis can be found on the NHS website here: https://www.nhs.uk/news/food-and-diet/drinking-3-4-cups-coffee-day-may-have-some-health-benefits/


SYSTEMATIC REVIEWS INTO CAFFEINE & SPORTS PERFORMANCE

Effects of caffeine intake on muscle strength and power: a systematic review and meta-analysis
Jozo Grgic, Eric T. Trexler, Bruno Lazinica and Zeljko Pedisic
Journal of the International Society of Sports Nutrition 2018
https://jissn.biomedcentral.com/articles/10.1186/s12970-018-0216-0

Systematic review into the effects of caffeine intake on muscle strength and power. Showed significant ergogenic effects of caffeine ingestion on maximal muscle strength of upper body and muscle power.


Efficacy of Acute Caffeine Ingestion for Short-term High-Intensity Exercise Performance: A Systematic Review
Astorino, Todd A; Roberson, Daniel W
The Journal of Strength & Conditioning Research: January 2010 
https://journals.lww.com/nsca-jscr/Fulltext/2010/01000/Efficacy_of_Acute_Caffeine_Ingestion_for.38.aspx

Systematic Review of effect of caffeine on short high intensity exercise. Eleven of 17 studies revealed significant improvements in team sports exercise and power-based sports with caffeine ingestion. Six of 11 studies revealed significant benefits of caffeine for resistance training. 

Effect of Caffeine on Sport-Specific Endurance Performance: A Systematic Review
Ganio, Matthew S; Klau, Jennifer F; Casa, Douglas J; Armstrong, Lawrence E; Maresh, Carl M
The Journal of Strength & Conditioning Research: January 2009
https://journals.lww.com/nsca-jscr/Fulltext/2009/01000/Effect_of_Caffeine_on_Sport_Specific_Endurance.46.aspx

Systematic review into studies that have examined effect of caffeine on time trial performance. It found caffeine ingestion can be an effective ergogenic aid for endurance athletes when taken before and/or during exercise in moderate quantities (3-6 mg per kg body mass). 


Effects of Caffeine Supplementation on Performance in Ball Games
Jingyi Shannon ChiaLaura Ann BarrettJia Yi ChowStephen Francis Burns
Sports Medicine December 2017, Volume 47https://link.springer.com/article/10.1007/s40279-017-0763-6

Systematic review into effect of caffeine on performance in ball games found ‘improvements in sprint performance were observed in 8 of 10 studies (80%), and vertical jump in 7 of 8 studies (88%)’. More research is required into effect on agility and accuracy.

Caffeine to optimize cognitive function for military mission-readiness: a systematic review and recommendations for the field
Cindy Crawford  Lynn Teo  Lynn Lafferty  Angela Drake  John J. Bingham Matthew D. Gallon  Meghan L. O’Connell  Holly K. Chittum  Sonya M. Arzola Kevin Berry
Nutrition Reviews, Volume 75, Issue suppl_2, 1 June 2017, Pages 17–35
https://academic.oup.com/nutritionreviews/article-abstract/75/suppl_2/17/3868861

The effects of caffeine supplementation on cognitive functioning in sleep-deprived subjects included improvements in attention and vigilance, complex reaction time, and problem solving and reasoning.


Effects of Coffee Components on Muscle Glycogen Recovery: A Systematic Review
Laís Monteiro Rodrigues Loureiro 1*, Caio Eduardo Gonçalves Reis 2, Teresa Helena Macedo da Costa 2
International Journal of Sport Nutrition and Exercise Metabolism 2018
https://journals.humankinetics.com/doi/abs/10.1123/ijsnem.2017-0342

‘Various coffee components had a neutral or positive role in the metabolism of glucose and muscle glycogen, whilst no detrimental effect was described’

 

A SELECTION OF STUDIES INTO THE EFFECTS OF CAFFEINE ON PERFORMANCE 


 The Metabolic and Performance Effects of Caffeine Compared to Coffee during Endurance Exercise

Adrian B. Hodgson, Rebecca K. Randell, Asker E. Jeukendrup
School of Sport and Exercise Science, University Of Birmingham
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0059561

This study examined whether there is any difference between vehicles for caffeine ingestion. It found performance times during cycling Time Trial to be significantly faster (∼5.0%) for both caffeine and coffee when compared to placebo and decaf coffee. Caffeine dose used was 5mg per KG of bodyweight.

Enhancement of 2000-m rowing performance after caffeine ingestion
Clinton R. Bruce, Megan E. Anderson, Steven F. Fraser, Nigel K. Stepto, Rudi Klein, William G. Hopkins, and John A. Hawley
Exercise Metabolism Group, Department of Human Biology and Movement Science, RMIT University, AUSTRALIA
https://s3.amazonaws.com/academia.edu.documents/42046850/Enhancement_of_2000-m_rowing_performance20160204-27525-1rxate7.pdf?AWSAccessKeyId=AKIAIWOWYYGZ2Y53UL3A&Expires=1527670570&Signature=CiAVopDIiYN%2BoztEaPX3TInHTpI%3D&response-content-disposition=inline%3B%20filename%3DEnhancement_of_2000-m_rowing_performance.pdf


This study examined impact of caffeine on rowing 2000m. It found ‘Ingestion of 6 or 9 mg of caffeine per KG produces a worthwhile enhancement of short-term endurance performance in a controlled laboratory setting.’ Performance times decreased by a mean of 1.2%.


‘Metabolic, catecholamine, and exercise performance responses to various doses of caffeine’
T. E. Graham, and L. L. Spriet
Journal of Applied Physiology March 1995
https://www.physiology.org/doi/abs/10.1152/jappl.1995.78.3.867

Caffeine or a placebo was taken 1hr before exercise in tablet form. Endurance was enhanced with both 3 and 6 mg/kg of caffeine (increases of 22 +/- 9 and 22 +/- 7%, respectively; both P < 0.05) over the placebo time of 49.4 +/- 4.2 min, whereas there was no significant effect on endurance with 9 mg/kg of caffeine. 

 

Effect of caffeine on exercise performance among overweight sedentary medical college students (1st year MBBS) of Jawaharlal Nehru Medical College
Sawangi (Meghe), Wardha, Maharashtra Das Rajesh Ranjan, Deshpande V.K and Biswas D.A
International Journal of Physiology, Nutrition and Physical Education 2017
https://pdfs.semanticscholar.org/348b/a980e40165566be63fd1389daaff4ec9494c.pdf

Eighteen healthy, overweight, sedentary, male students completed 15 minutes steady state cycling exercise at a standardized power output equating to 65% of HR max (part-1) followed by 10 min stationary cycling where they were required to cycle with maximum effort after ingestion of caffeine (5mg per kg) 60 min prior to exercise.  Pulse rate decreased with moderate dose of caffeine ingestion during submaximal exercise which indicates decrease in heart rate. After caffeine ingestion energy expenditure in the 2nd part (10 min maximal) of exercise increased slightly but it is significantly increased in 1st part of exercise (15 min sub maximal exercise). ‘The result of the investigation demonstrated that caffeine in moderate dose has got beneficial effect over cardiovascular responses to dynamic exercise.’