Because drinking coffee has a mild diuretic effect, many assume that coffee is dehydrating. As it turns out, coffee consumption can be more helpful than harmful when it comes to hydration levels.
Does Coffee Dehydrate You?
Dehydration is when the body loses more fluid than it retains for normal functioning via sweating or urine output. Symptoms of dehydration include
- Extreme thirst
- Dark urine
- Muscle cramps
Daily coffee intake does not cause that kind of fluid loss. Because caffeine can cause the urge to urinate perhaps more than normal, we may feel as though our hydration status has been altered. Turns out this is a faulty perception.
The notion that coffee dehydrates stems from a study conducted in 1928. The findings have since been debunked. In fact, a study published by PLOS ONE Journal showed no evidence of dehydration due to coffee intake.
While coffee can cause some initial diuresis, it wears off rather quickly. It doesn’t cause a sustained reduction in fluid balance.
How much coffee can you drink before it dehydrates you? The amount of coffee it would take to cause dehydration would be well beyond the FDA recommended daily amount. The FDA advises consuming no more than 400 milligrams of caffeine in a day, or about 4 mugs.
Caffeine’s Diuretic Properties
Diuretics are substances that cause the kidneys to increase urine production. This process (called diuresis) flushes excess salt and water from the body. Technically, the term, diuretic, refers to medication designed to cause diuresis so that the heart doesn’t have to work so hard pumping all of that fluid throughout the body. Conditions requiring diuretics include
- Congestive heart failure
- Edema (tissue swelling)
- High blood pressure
- Liver failure
Some foods and beverages (alcohol, ginger, tea, etc.) act as natural diuretics and are sometimes referred to more generally as diuretics.
Response to Caffeine is Individual
Frequency of caffeine consumption can play a role in whether or not you experience diuretic effects. For instance, regular coffee drinkers will likely be less susceptible to frequent bathroom breaks because their bodies are accustomed to their caffeine intake.
Casual coffee drinkers could be more sensitive to those diuretic effects. Also, they might experience the effects of caffeine more quickly, because their bodies just aren’t as used to it.
Everyone responds to caffeine differently. Some may feel more pronounced effects than others. Individual responses to caffeine depending on factors like:
- Caffeine sensitivity
- Frequency of consumption
Does coffee make you thirstier? Coffee, like any drink that’s not water, can increase thirst. Even so, thirst does not necessarily mean you’re dehydrated. Thirst simply indicates that your body would like some fluids. The National Health Service believes thirst is an initial signal that you may become dehydrated.
Caffeine in Different Types of Coffee
Caffeine content varies widely among coffee. Type of coffee beans, roast, and brew method all play a role in how much caffeine makes it into your cup of joe.
Though Arabica coffee beans are more popular, Robusta beans have almost double the amount of caffeine. Light roast coffees tend to have more caffeine than dark roast coffees.
Based on a 2019 project by Coffeeness, coffee has more caffeine than has been purported in the past several years.
Regular drip coffee, the most common brew method for Americans, contains about 170 mg of caffeine per 8.5 oz cup of coffee.
The foundation of many specialty drinks, Espresso has about 68 mg of caffeine per .8 oz shot.
Cold brew steeped for 24 hours has a whopping 280 mg of caffeine per glass.
Decaf coffee is not caffeine-free, as we might think. Decaf contains 2-7 mg of caffeine per 8 oz cup, making it a misnomer.
Not everyone uses coffee as their caffeine source. Energy drinks receive plenty of shelf space in grocery stores and a designated refrigerator section in convenience stores. Red Bull has 80 mg of caffeine and Rockstar has 160 mg; although, in this category of caffeinated beverages, several range from 300-400 mg of caffeine per can.
Though caffeinated drinks can contain diverse amounts of caffeine, the result is usually the same across the board — a trip to the restroom. Rest assured, this is not a dehydrating effect and you’re not losing more fluid than you should.
Coffee & Fitness
Tracking Coffee for Water Intake Goals
It’s no secret that water is vital to our health. The National Academies of Sciences, Engineering, and Medicine recommends daily fluid intake of 3.7 liters (15.5 cups) for men and 2.7 liters (11.5 cups) for women. However, 20% of fluids come from foods (fruits and veggies are mostly water after all).
Though nutritionists advocate that most daily fluids should come from drinking water, other beverages count. Healthy alternatives to water include:
- Sparkling water
- Unsweetened fruit juice
- Vegetable Juice
- Black coffee
Does coffee count as water intake? Yes, coffee counts towards your daily water intake. Coffee is 98.75% water and should be calculated accordingly. Contrary to popular belief, coffee hydrates the body.
Coffee Before Working Out
Workout clothes? Check.
Water bottle? Check.
Gym I.D.? Check.
Many don’t consider drinking coffee before exercising. Sports drinks are associated with exercising because of how they replenish electrolytes. But coffee? Interestingly, studies are showing some positive results.
- Enhanced movement velocity
- Increased muscular strength
- Improved aerobic endurance
Caffeine and exercise make a great combo; however, be sure to monitor caffeine intake, as you don’t want to overdo it. Side effects of too much caffeine are
- Heart palpitations
Caffeine is often more associated with its effects on the central nervous system. It’s worth noting that caffeine can affect physical performance as well.
Drink Healthy Coffee
The bottom line is that coffee can help with hydration. If you want the most out of your cup of coffee health-wise, black coffee is best.
Milk and a little sugar are fine as well. Creamers, excessive amounts of sugar, syrups, and sweeteners can get coffee lovers in trouble. The cumulative effects can cause health issues.
Don’t fret, you don’t have to completely cut out specialty drinks. Frappuccinos and lattes make great occasional treats. For your daily dose of caffeine, check out our recommendations for healthy coffee.
If you’re looking for a smooth coffee that doesn’t need additives, check out Golden Ratio!
- Consumption of coffee or caffeine and serum concentration of inflammatory markers: A systematic review
- The neuroprotective effects of caffeine in neurodegenerative diseases - PMC
- How Much Caffeine Is Really in Your Coffee? Find Out Here!
- Caffeine increases maximal fat oxidation during a graded exercise test: is there a diurnal variation? | Journal of the International Society of Sports Nutrition | Full Text
- International society of sports nutrition position stand: caffeine and exercise performance