Caffeine Supplementation: Debunking Myths and Uncovering the Truth for Endurance Athletes

1. Moderate caffeine use does not cause dehydration at rest

• Caffeine intake of 3mg/kg or less than 300mg does not affect the volume of urine. 
• However, massive doses, like over 6mg/kg or 500mg may cause some dehydration. 

2. Dehydration and caffeine during exercise

• Studies show that moderate caffeine intake does not cause dehydration.
• There may be some dehydration in the heat with a large caffeine intake. 
• It’s best to make sure you’re drinking enough fluids to offset any potential issues. 

3. Caffeine seems to increase fat oxidation but the jury’s out on caffeine and weight loss

• Studies with moderate (3mg/kg) amounts of caffeine show improved fat oxidation during exercise.
• There are lots of conflicting issues with studies that show weight loss from caffeine intake so it’s not a thing right now. 

4. There seems to be no difference in caffeine’s effect on lower vs. upper body strength

• Some studies have shown differences in caffeine’s effect on chest presses vs. back squats, for example.
• The differences are likely due to individual dosing, strength, and activity level. 

5. Caffeine may improve mood for some people, but its effect is very individualistic

• Some studies have shown a positive effect of caffeine on depression and mood enhancement in general. 
• However, other studies have shown an increase in anxiety and sleeplessness due to caffeine. 

6. Caffeine can’t kill you - unless you take over 5 grams! 

• It would be tough to take a lethal dose of caffeine when consuming coffee and tea. 
• There’s a minimal risk to your health with a “normal” dose of daily caffeine. 

7. There may be some differences between male and female reactions to caffeine

• However, caffeine intake improves performance for both men and women, although there may be a greater effect on men. 
• There may be some differences for women using oral contraceptives. 
• Female hormones and physiological differences account for caffeine being possibly less effective for women. 

8. It’s not clear if regular caffeine consumption affects performance

• It’s unclear if those of us who drink coffee on the regular lose some of the performance benefits. 
• However, most evidence suggests habitual caffeine use does not negatively affect performance.
• Habitual users may need an additional does of 6 to 9mg of caffeine for optimal performance.

9. Most people react to caffeine positively for performance

• “Caffeine is one of the few well-established ergogenic aids that consistently enhances various aspects of exercise performance, including muscular endurance, muscular power, muscular strength, sprinting, jumping, throwing, and endurance.”
• Caffeine uptake is not generally affected by genetics. 
• The performance-enhancing effects of caffeine are not always repeatable, meaning they won’t work every time. 
• People react to caffeine very differently. 

10. Caffeine may have some link to heart issues but it’s highly individualistic

• Caffeine can benefit cardiovascular and cognitive functioning as well as improve general health.  
• However, caffeine can make some heart problems worse, such as atrial fibrillation. I’m finding that on a ride when my ventricular tachycardia is acting up, caffeine definitely makes it worse. 
• The effect of caffeine on a person’s cardiovascular system is highly dependent on dose, means of consumption, metabolic and genetic differences. 

11. Lots of caffeine in coffee may cause issues with bone density

• You have to drink more than four cups of coffee a day to have any negative effect. 
• Drinking about two cups a day improves bone density. 
• There are a lot of confounding issues in the research about negative effects so more research is necessary. 

12. Pregnant women should likely avoid caffeine

• Caffeine may cause adverse pregnancy outcomes. 
• Caffeine consumption below 200 to 300mg is considered safe. 

13. Caffeine is probably not addictive for most people

• Caffeine withdrawal is an official diagnosis and Caffeine Use Disorder is a condition needing more study by the diagnostic manual of mental disorders. 
• Caffeine can be misused by some. 
• Caffeine withdrawal is a thing. 

14. Waiting to drink your coffee does not affect an afternoon crash

• Afternoon fatigue is likely connected to circadian rhythms. 
• Daytime typical caffeine intake is not likely associated with afternoon sleepiness.
• I still like a little caffeine after lunch! 

Three things to know about caffeine supplementation misconceptions

1. Generally, moderate caffeine consumption is good for most people. 
2. High doses can affect pregnancy, heart issues, and bone density, among other health issues.
3. Coffee is not necessarily addictive, but caffeine withdrawal is a real thing. 

Need more? 

Unlock the secrets to mastering gravel racing with my FREE 24-page Guide to Gravel Racing! Get yours here.

SIGN UP FOR A FREE Virtual Coffee so we can discuss your goals, ask questions, and talk about making your endurance training more effective, fun, and Simple.

Paul Warloski is a:

• USA Cycling Level 2 Coach
• RRCA Running Coach
• Training Peaks Level 2 Coach
• RYT-200 Yoga Instructor
• Certified Personal Trainer