We have learned that caffeine ingested in doses under 500 mg during exercise does not cause dehydration, and there is ample evidence to prove it.1 But what about the scholarly support of caffeine as a diuretic? That also is not as solid as most people think. But if caffeine does cause diuresis and thus a negative fluid balance, this is important for those who treat musculoskeletal conditions. Why? Because a hydrated cell is an anabolic cell, and whether a patient is injured during sports, work or transportation, any deficiency will retard healing, including fluid balance.
Caffeine's ability to cause diuresis has rarely been challenged since a paper published in 1928 first demonstrated it.2 The paper was often cited and rarely challenged for decades, even though it only studied three patients. Recently, an excellent review article by L.E. Armstrong and colleagues at the University of Connecticut examined 15 studies (totaling 23 different protocols) that focused on caffeine's effect on fluid balance.3 All of the studies selected included water or placebo beverage compared to a caffeinated drink. The caffeine dosage ranged from 45 mg to 642 mg, and nine of these studies were four hours or less. The others were six, 16, 24, 24 and 72 hours, respectively, along with one 13-day study that I reviewed in detail last month.1 Eight of the studies were at rest, seven included exercise, and one compared the effects of caffeine at rest to the effects of caffeine with exercise.4 In the results, six of the 23 protocols showed that caffeine caused significant diuresis (see Table 1). The other 17 protocols did not find a diuretic effect (see Table 2).
| Table 1 - Diuretic Effect | |
| Caffeine (mg) | Length of Study |
| 642 | 24 hours |
| 586 | 4 hours |
| 360 | 4 hours |
| 250 | 3 hours |
| 250 | 3 hours |
| 240 | 6 hours |
| Table 2 - No Diuretic Effect | |
| Caffeine (mg) | Length of Study |
| 586 | 4 hours** |
| 553 | 1 hour |
| 452 | 16 hours |
| 452 | 11 hours |
| 300 | 4 hours |
| 300 | 3 hours |
| 300 | 3 hours |
| 274 | 2 hours |
| 253 | 24 hours |
| 245 | 4 hours |
| 226 | 16 hours |
| 226 | 11 hours |
| 150 | 4 hours |
| 150 | 3 hours |
| 150 | 3 hours |
| 114 | 24 hours |
| 90 | 4 hours |
| 45 | 4 hours |
The findings were as follows:
Conclusion
It is apparent that the generally accepted view that caffeine is a diuretic and/or causes dehydration is incorrect. There is no question that population responses to caffeine will not be uniform and diuresis will occur in selected individuals. However, there is not a substantial difference for the general population between caffeinated and noncaffeinated beverages regarding fluid balance. For those worrying about dehydration on a hot day, caffeinated fluids are clearly superior to no fluids. Armstrong, et al., summarized their work as follows:
"There is no evidence to suggest that moderate caffeine intake (less than 456 mg) induces chronic dehydration or negatively affects exercise performance, temperature regulation, and a circulatory strain in the hot environment. Caffeinated fluids contribute to the daily human water requirement in a manner similar to pure water ... The evidence indicates that consuming a moderate level of caffeine results in a mild increase in urine production ... This dieresis may or may not be significantly greater than a control fluid."3
References
Many relevant diagnostic signs are not performed deliberately by the examiner or by the patient at the examiner’s direction. They are observed as the patient reacts to their condition. Fortin’s finger sign, Minor’s sign, and Vanzetti’s sign are three examples of this principle.
On Feb. 1, 2024, two more legislators – John R. Carter (R-Texas) and Robert “Bob” Good (R-Va.) – co-sponsored the Chiropractic Medicare Coverage Modernization Act of 2023, bringing the co-sponsor total to 155, two more than the total achieved over the entire two-year congressional cycle in which identical legislation last appeared (2021-22).
While working at the Lovelace Medical Center in Albuquerque, N.M., one of the primary care physicians stated that imaging every patient prior to receiving chiropractic was not medically necessary. It was at that point I reconsidered the need for the imaging of every patient to avoid malpractice.
