Everything you need to know about caffeine and running

By Courtney Berg

Caffeine is a powerful substance that can improve physical and mental performance during exercise! Individual tolerance to caffeine varies and it is advised to be mindful of personal limits and avoid excessive consumption. Read more to learn about the benefits of caffeine on athletic performance and considerations to tailor your intake to your personal tolerance and wellness goals.

Are there benefits to consuming caffeine before a workout?

Caffeine is a popular ergogenic aid, meaning it has the potential to enhance exercise performance! Below are some of the benefits of caffeine in the context of workout performance:

  • Increased Endurance: Caffeine can enhance endurance by allowing optimal intensity to be sustained for longer.
  • Improved Strength & Power: Caffeine can increase the release of adrenaline, a hormone that prepares the body for physical exertion including improved strength and power.
  • Enhanced Mental Focus: Caffeine acts as a central nervous system stimulant, improving alertness and concentration. This can be particularly beneficial during activities that require focus and coordination!
  • Reduced Perceived Effort: Caffeine may lower the perception of effort during exercise, making the same workload feel less challenging.
  • Faster Reaction Time: Caffeine has been shown to improve reaction time and cognitive function, which can be beneficial for athletes participating in sports that require quick decision-making and reflexes.
  • Increased Fat Oxidation: Caffeine can enhance the use of fat as a fuel source during exercise. This is particularly relevant for endurance activities as it helps spare glycogen which may contribute to improved performance during prolonged efforts!
  • Potential Benefits for High-Intensity Exercise: The increased release of adrenaline may contribute to improved performance in high-intensity efforts like sprints, resistance training, or HIIT.

What beverages or foods are a source of caffeine?

Caffeine is found in a variety of food and beverages including various types of coffee, teas, energy drinks, workout gels, pre-workout supplements, electrolyte drinks, and chocolate. It is important to be aware that many caffeine supplements contain additional substances and stimulants that may not be safe or suited to your unique goals. Speak with a trusted health-care provider such as a Registered Dietitian if you have questions about caffeine supplements!

How much caffeine should I consume before a workout?

The optimal amount of caffeine before a workout can vary from person to person due to factors such as individual sensitivity to caffeine, body weight, and tolerance.

Sports nutrition research suggests that a dose of 3-6 milligrams per kilogram of body weight can be effective for enhancing exercise performance when consumed approximately 60 minutes before a workout. For example, a 150 pound (68.2kg) individual would benefit from 205 mg to 410 mg of caffeine consumed 60 minutes before exercising. Registered Dietitians recommend trialing your caffeine strategy in training to ensure it is tolerated come race day or competition!

It’s important to note that individual responses to caffeine can vary, and some people may experience negative side effects even with moderate doses. Furthermore, Health Canada recommends no more than 400mg of caffeine per day for healthy adults. Therefore, depending on the body weight of the athlete, the sports nutrition recommendations may be inconsistent with the recommended maximum daily intake of caffeine recommended by health agencies. For this reason, it can be important to consult with a Registered Dietitian to tailor your caffeine intake not only to athletic performance goals but your overall wellness.

Should I consume caffeine during my endurance events?

While fluids, sodium, and carbohydrates are the three most important nutrients to consider when fueling for endurance events >90 minutes, you may choose to experiment with a small “top up” dose of caffeine. Some athletes partner pre-race caffeine supplementation with 20-100mg of caffeine per hour during longer endurance events. “Topping up” with caffeine likely is not necessary for endurance events <3 hours, but may be beneficial for endurance events >3 hours to improve mental performance and reduce the perception of fatigue.

Are there drawbacks to consuming caffeine after a workout?

There are no specific detriments to consuming caffeine after a workout beyond the potential drawbacks listed below.

What are the potential drawbacks to consuming caffeine?

While caffeine consumption is generally considered safe, excessive intake or individual sensitivity to caffeine can lead to negative impacts. If you experience these detrimental side effects, it may be worth evaluating if it would be best to eliminate or reduce caffeine sources.

  • Insomnia and Disrupted Sleep: Caffeine is a stimulant that can interfere with sleep. Consuming caffeine, especially in the afternoon or evening, may lead to difficulty falling asleep, reduced sleep quality, or disrupted sleep patterns. Most people benefit from limiting caffeine 8-12 hours before bed. Considering that high-quality sleep is one of the most impactful habits for exercise recovery and performance, it may be worth skipping caffeine for workouts scheduled later in the day in order to protect your sleep!
  • Anxiety & Nervousness: High doses of caffeine can cause jitteriness, restlessness, and increased nervousness. Some individuals are more sensitive to these stimulant effects than others. Furthermore, individuals who experience anxiety may find that caffeine worsens symptoms. In this case, eliminating or reducing caffeine may be best suited to your mental and physical health!
  • Increased Heart Rate and Blood Pressure: Caffeine can temporarily raise heart rate and blood pressure. While this effect is generally mild, individuals with certain heart conditions, hypertension, or anxiety should be cautious with caffeine
  • Gastrointestinal Distress: Caffeine can cause gastrointestinal discomfort, including acid reflux, indigestion, diarrhea, and stomach upset. If caffeine worsens digestive symptoms, especially before a workout, it may not be the best option for your athletic performance.
  • Dependency and Withdrawal: Regular consumption of caffeine can lead to dependence, where the body becomes accustomed to the stimulant effects. Withdrawal symptoms such as headaches, irritability, and fatigue may occur if caffeine intake is suddenly reduced.

When should I be careful about caffeine intake?

  • If you’re Pregnant: Pregnant individuals are often advised to limit caffeine intake due to potential risks to the developing fetus. It is recommended to limit caffeine to <300mg if trying to conceive or if you are pregnant.
  • If you’re Breastfeeding: While moderate caffeine intake is generally considered safe during breastfeeding, it’s advisable to monitor baby’s behavior. Some infants may be more sensitive to caffeine and excessive intake by the breastfeeding mother can lead to irritability or sleep disturbances for the baby.
  • If you have Certain Medical Conditions: Individuals with certain medical conditions such as heart arrhythmias, hypertension, anxiety disorders, or gastroesophageal reflux disease (GERD) may need to limit their caffeine intake. Caffeine may exacerbate symptoms so it’s valuable to discuss caffeine consumption with your health-care provider in these cases.
  • If you’re Taking Supplements and Medications: Caffeine can alter the absorption and metabolism of certain supplements and medications. For example, caffeine can inhibit the absorption of iron and calcium supplements. Therefore, it is advised to avoid consuming caffeine-containing beverages close to the time of iron and calcium
    supplements. Caffeine can also impact the effectiveness of medications such as some thyroid medications, antibiotics, and antidepressants. Consult with a health-care professional if you have any concerns or questions about potential interactions with caffeine.
  • Individual Sensitivity: People vary in their tolerance to caffeine. Some individuals may experience side effects like jitteriness, increased heart rate, sleep disruption, or digestive issues even with moderate caffeine intake. Pay attention to how your body reacts to caffeine and adjust your consumption accordingly.

Reflect on your unique experience with caffeine to determine whether and how much caffeine is suited to your overall wellness and exercise performance!

If you have specific concerns or questions about caffeine and its effects on your health or fitness goals, consider consulting with a healthcare professional such as a Registered Dietitian at Vitality Nutrition who can provide personalized advice based on your individual circumstances!


Courtney Berg is a Registered Dietitian and the owner of Vitality Nutrition, a collective of Registered Dietitians supporting clients in-person in Saskatoon and Regina and virtually across Saskatchewan. Courtney and her team of nutritionists incorporate a unique and meaningful approach to food, fitness, and performance that empowers their clients to build life-long habits and create lasting results.