Are you the type who can’t function until your first cup of coffee or do mornings find you bright-eyed and ready to go? For many of us, mornings are messy, chaotic and fueled by the smell of coffee or the promise of that caffeine boost that jumpstarts the day.
Caffeine is one of the most popular stimulants worldwide. In fact, around 85% to 90% of adults in the U.S. consume caffeine in some form, whether it's coffee, tea, soda, energy drinks, chocolate or certain foods and supplements.
While caffeine can give us that boost to start our day, how much is too much and when should you cut back?
Stephanie Olson, RDN, CDCES, a registered dietitian nutritionist with Banner Health, explains what caffeine can do for you, the risks to watch for and how to enjoy it safely.
What is caffeine?
“Caffeine is a naturally occurring stimulant found in many plants used to make coffee, tea, chocolate and other flavorings,” Olson said.
Plant sources of caffeine include:
- Coffee beans, leaves and seeds
- Tea leaves
- Cacao beans (used for chocolate)
- Kola nuts
- Yerba mate
- Guarana berries
It’s also added to soda, energy drinks, pre-workout powders and other products.
“When consumed, caffeine increases chemicals in the brain that stimulate the central nervous system, the control center that controls your brain and body,” Olson said. “It blocks a chemical called adenosine, which normally makes you feel tired. By blocking adenosine, caffeine helps you stay alert and focused.”
The benefits of caffeine
Caffeine doesn’t just boost alertness and mental focus. It has other positive effects as well. Here’s how:
1. Supports your heart and circulation
Caffeine can increase heart rate and efficiency, helping your heart pump blood more effectively.
“It also causes vasodilation, which widens blood vessels so that oxygen and nutrients flow more easily to your brain and muscles,” Olson said. This can make you feel more energized and improve performance in daily tasks and workouts.
2. Helps your lungs and breathing
“Caffeine acts as a smooth muscle relaxant, including your respiratory bronchioles (the small airways in your lungs),” Olson said. This can make breathing easier, especially during exercise or when your body needs more oxygen or for those with COPD or asthma.
“Caffeine has also been used in hospitals to help manage apnea in premature infants, a condition where babies briefly stop breathing,” Olson said. “It is used as a respiratory stimulant, which helps improve lung function and breathing rhythm.”
3. Boosts physical performance
“Caffeine can also help you power through a workout,” Olson said. “That’s why it’s a common ingredient in sports and endurance supplements.” It increases adrenaline, the hormone that helps your body perform under stress or exertion, while reducing fatigue so you can keep going longer.
“Caffeine also helps your body use fat for fuel more efficiently by boosting a process called lipolysis, the breakdown of stored fat into energy,” Olson said. For athletes or anyone exercising regularly, this can mean better stamina, endurance and muscle performance.
4. May support brain health
Emerging research suggests moderate caffeine consumption may protect memory and lower the risk of certain diseases like Parkinson’s and Alzheimer’s. While more studies are needed, caffeine seems to have positive effects on brain function over time.
5. Boosts mood and motivation
That little cup of coffee or tea in the morning might do more than wake you up; it can also help you feel happier and more engaged. By increasing neurotransmitters, caffeine can improve mood, motivation and even your ability to handle stress.
How much caffeine is safe?
The Food and Drug Administration (FDA) recommends that most healthy adults limit caffeine to 400 mg per day.
Here’s how much caffeine is typically found in popular beverages:
- 8 oz. brewed coffee: 80-200 mg
- 8 oz. black tea: 50-80 mg
- 8 oz. green tea: 30-50 mg
- 12-16 oz. energy drink: 100-300 mg
- Decaffeinated coffee: 2-15 mg
Remember that caffeine also shows up in chocolate, some over-the-counter (OTC) pain relievers and some workout supplements.
The risks of too much caffeine
While caffeine has plenty of benefits, it can also cause problems when you take in too much or too close to bedtime.
- Sleep issues: Trouble falling asleep or poor sleep quality
- Anxiety and jitteriness
- Heart rate and blood pressure spikes
- Digestive problems: Upset stomach, nausea or diarrhea
- Interactions with medications: Always check with your doctor if you take prescription drugs
- Dependence: Regular use may lead to withdrawal symptoms like headaches or fatigue if you stop suddenly
A note about energy drinks: They may also include sugar and other stimulants, such as herbal supplements, intended to increase alertness and boost energy. The sweetness of these drinks makes it easier to drink more than one.
“This can put added stress on the heart and nervous system, raising heart rate and blood pressure,” Olson said. “This is especially concerning for children and teens who may be drawn to these sweet energy drinks.”
[Learn about the risks of coffee, soda and energy drinks for children.]
Who should limit or avoid caffeine?
Some people are more sensitive to the effects of coffee or have conditions that make caffeine less safe. You may want to limit or avoid coffee if you:
- Are pregnant or breastfeeding: “In pregnancy, caffeine does cross the placenta,” Olson said. “While there isn’t a recommendation to eliminate caffeine, it is suggested to limit to less than 200-300 mg a day.”
- Have heart problems or high blood pressure: Caffeine can temporarily raise heart rate and blood pressure, which may increase risk for some people with heart conditions.
- Have anxiety or sleep disorders: Caffeine can make anxiety, restlessness or insomnia worse.
- Take certain medications: Some prescriptions and OTC medicines interact with caffeine.
- Are a child or teen: Young people are more sensitive to caffeine and too much can affect focus, mood and sleep.
“Recommendations for children can differ,” Olson said. “Some health agencies state that up to 100mg a day is considered safe, while others state there is no amount of caffeine that is considered safe for children up to 18 years of age.”
Tips to manage or reduce caffeine
You don’t have to go cold turkey to cut back. Olsson recommends:
- Choose natural sources: Coffee and tea provide antioxidants and fewer additives than energy drinks and soda. Herbal tea has zero caffeine.
- Use decaf or half-caf: Swap one or more cups of coffee for decaf.
- Time your caffeine: Stop consuming by 10 a.m. if it affects sleep.
- Wean gradually: Reduce one drink at a time instead of quitting suddenly.
- Stay hydrated: Drink water with caffeinated drinks to avoid dehydration.
- Monitor your body: Jitters, racing heart, stomach upset or sleep problems may signal too much caffeine.
Bottom line
Caffeine can be part of a healthy routine for most adults when consumed in moderate amounts. The key is balance and listening to your body. Know your limits and make changes if you notice sleep, mood or heart-related issues.
If you have concerns about your caffeine and health, talk to your health care provider or a Banner Health specialist.
