Coffee, Energy Drinks and Fatigue: What Actually Works? October 30, 2026 Coffee, Energy Drinks and Fatigue: What Actually Works? When the afternoon slump hits, a coffee or energy drink can feel like the quickest solution. Caffeine can certainly make you feel more alert, but it doesn’t replace sleep. So, when you’re tired, what actually works? Why caffeine gives you a boost Caffeine can improve attention, alertness and reaction time, particularly when you’re tired. A typical cup of brewed coffee contains around 80 to 100 mg of caffeine, although amounts vary between drinks.1 It works partly by blocking adenosine receptors in the brain.1 Adenosine is a chemical that builds up while you’re awake and contributes to feelings of sleepiness. By temporarily stopping adenosine from acting on these receptors, caffeine can help you feel more awake. Why the boost doesn’t last forever Caffeine doesn’t stop your body from producing adenosine. Once the caffeine wears off, adenosine can bind to its receptors again and sleepiness can return. Regular caffeine consumption can also lead to tolerance, meaning your usual coffee may not give you the same boost over time.1 Most importantly, caffeine cannot compensate indefinitely for inadequate or poor-quality sleep. What about exercise? Sometimes the best pick-me-up might not come in a cup. Even a short burst of cardiovascular exercise can increase alertness, speed up mental processing and support memory.2 One small study found that 10 minutes of stair climbing produced a greater self-reported energy boost than 50 mg of caffeine.2 While the study was small, a brisk walk or a few minutes of movement may be worth trying when your energy dips. How to use caffeine wisely For most adults, keeping total caffeine intake below 400 mg per day is generally recommended.1 Remember that caffeine isn’t just found in coffee. Other sources, including energy drinks, can add to your daily intake. Timing matters too. Drinking coffee within six hours of bedtime can interfere with sleep, so consider keeping caffeinated drinks to earlier in the day.1 Be mindful of added sugar as well, particularly in sweetened coffees and energy drinks. Some caffeinated drinks can contain substantial amounts of added sugar, and consuming sugar can contribute to fatigue in people with diabetes.1 Choosing lower-sugar options and drinking plenty of water can be sensible ways to manage your caffeine intake. The bottom line Caffeine can be a useful temporary boost, but good-quality sleep, regular movement and hydration remain important for managing fatigue. If you regularly feel exhausted despite getting enough sleep, or find yourself relying heavily on caffeine to get through the day, speak with your doctor. Persistent fatigue can have an underlying cause that is worth investigating. References 1. summer, jay. “Why Coffee Can Make You Tired.” Sleep Foundation, 17 Aug. 2021, https://www.sleepfoundation.org/sleep-faqs/why-does-coffee-make-me-tired. Accessed 28 Aug. 2026 2) Tello, Monique. “Exercise versus Caffeine: Which Is Your Best Ally to Fight Fatigue? - Harvard Health Blog.” Harvard Health Blog, 8 June 2017, https://www.health.harvard.edu/blog/exercise-versus-caffeine-which-is-your-best-ally-to-fight-fatigue-2017060811843. Accessed 28 Aug. 2026.
