Let's talk coffee


In one of my previous post about caffeine (copy page address below), I tried to educate about some of the benefits of drinking coffee and caffeine. It has become increasingly common for individuals to self-righteously proclaim they are "quitting" drinking coffee, and while some of the benefits to decreasing your coffee intake could include less shakes, less staining of teeth, and more cash in your pocket, there are some upsides to drinking the beverage, too. One of the main themes of my previous post was to figure out through the research if the myth of the dehydrating effects of caffeine was true. This post could be summed up by the below excerpt: "The most ecologically valid of the published studies offers no support for the suggestion that consumption of caffeine-containing beverages as part of a normal lifestyle leads to fluid loss in excess of the volume ingested or is associated with poor hydration status. Therefore, there would appear to be no clear basis for refraining from caffeine containing drinks in situations where fluid balance might be compromised."

http://www.carlarobbins.com/#!Does-coffee-dehydrate-you/f78aj/56fd873b0cf21ff2b5fc16dd

A theme of another one of my posts on caffeine included research on how caffeine can effect endurance performance. This topic has been researched extensively, and the benefits of caffeine for endurance, and potentially other activities, is hardly debatable - even with individual factors accounted for. This post (copy below), can be summer up by the excerpt:

"Dose should be individualized for each athlete, and consumption of caffeine pills should never be tested on race day - but instead tested through trial and error prior to the athlete's race. A dose of 2-5mg/kg has been shown to increase performance by 3% on average, with minimal gastric upset (keeping in mind that there are responders and non-responders to caffeine based on habituation). Doses of >5mg/kg have been shown to increase performance on average by 7%, but again, outliers do exist. One thing is clear in the literature, which is that there are no further increases in performance after 9mg/kg consumption of caffeine, and this size of a dose can be associated with side effects such as being jittery, having GI upset, headaches, tachycardia and nausea (Shearer & Graham, 2014)."

http://www.carlarobbins.com/#!Endurance-and-Caffeine/f78aj/564bdeb00cf214123004e4bf

So, diving further into the physiology of caffeine and it's most commonly consumed form, coffee, let's learn more about it's effects all around the body: -Caffeine binds to adenosine receptors in the body, and because such receptors are found in many tissues in the body, it helps explain caffeine’s diverse effects in the body. Since it is non-selective, it is a difficult drug to study. For example, adenosine is a neuromodulator, believed to play a role in promoting sleep and suppressing arousal. Acting through this mechanism, caffeine may modulate central fatigue and influence ratings of perceived exertion, perceived pain, and levels of vigor, all of which may lead to performance improvements.

-In the liver, caffeine increases net hepatic glucose uptake, but also increases its lactate output. On the morning of your lactate tests in my lab, we ask you avoid caffeine for this reason! -In the kidneys, caffeine is a diuretic, stimulating mild fluid loss. As we habituate to caffeine intake, this diuretic effect is lost.

-In the gut, caffeine slightly increases gut motility. However, it is hard to find a lot of literature on this.

-In the heart, caffeine use slightly increases heart rate. It also has mild effects on blood pressure, increasing blood pressure by 5-10 millimeter of mercury for the naïve user. This goes back to the adenosine receptors, and caffeine's antagonistic effect on the receptors. -In adipose tissue, it stimulates lipolysis. Lipolysis is the breakdown of fats from fat stores in the body. Overall don't think weight loss, think mild changes to metabolism every time you drink a cup that are acute, and don't accumulate with more cups.

-In the brain, caffeine crosses the blood brain barrier, altering mood. For some, mood can be negatively affected, while in others, mood can be enhanced. Since caffeine binds to adenosine receptors, and they typically bind with adenosine to enhance sleep, caffeine makes us feel more awake. There are individual differences here - so some people need one shot of espresso, and others need a Red Eye (Americano with no water sub coffee)!!

-On a whole body basis, the combined effect is an increase in thermogenesis. Consumption of 5mg/kg body weight to a individual who does not regularly consume caffeine results in an increased energy expenditure of ~100 calories.

-Caffeine consumption is also known to decrease food consumption and have profound effects on carbohydrate management.

In conclusion, coffee is not ALL bad. In fact, most people find it quite delicious! Read about the facts, challenge yourself to learn more, and do your coworkers a favor and treat them to a coffee today..

Strength and Fitness is VITAL to your health and well being. Maybe caffeine is too! #VitalStrength

References

Bell, D. G., Jacobs, I., & Zamecnik, J. (1998). Effects of caffeine, ephedrine and their combination on time to exhaustion during high-intensity exercise. European Journal of Applied Physiology and Occupational Physiology, 77(1998), 427–433. doi:10.1007/s004210050355

Burke, L. M. (2008). Caffeine and sports performance. Applied Physiology, Nutrition, and Metabolism = Physiologie Appliquée, Nutrition et Métabolisme, 33(6), 1319–34. doi:10.1139/H08-130

Ganio, M. S., Klau, J. F., Casa, D. J., Armstrong, L. E., Maresh, C. M. (2009). Effect of Caffeine on Sport-Specific Endurance Performance: A Systematic Review. Journal of Strength and Conditioning Research, 23(1), 315–324.

Harland, B. F. (2000). Caffeine and nutrition. Nutrition, 16(7-8), 522–526. doi:10.1016/S0899-9007(00)00369-5

Robertson, D., Wade, D., Workman, R., Woosley, R. L., & Oates, J. a. (1981). Tolerance to the humoral and hemodynamic effects of caffeine in man. Journal of Clinical Investigation, 67(4), 1111–1117. doi:10.1172/JCI110124

Shearer, J. (2014). Methodological and metabolic considerations in the study of caffeine-containing energy drinks. Nutrition Reviews, 72, 137–145. doi:10.1111/nure.12131

Shearer, J., & Graham, T. E. (2014). Performance effects and metabolic consequences of caffeine and caffeinated energy drink consumption on glucose disposal. Nutrition Reviews, 72 Suppl 1, 121–136. doi:10.1111/nure.12124

Tarnopolsky, M. a. (1994). Caffeine and Endurance Performance. Sports Medicine, 18(2), 109–125. doi:10.2165/00007256-199418020-00004


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