More caffeine, less control: How drinking too much coffee before driving can slow your reflexes and cloud judgment
Health experts have said that caffeine can keep drivers awake, but too much can cause tremors, poor decisions, and slower reactions.
Coffee is the go-to fix for everyone around the world. Even drivers like to drink it before hitting the highway. But experts have warned that caffeine overload can be as risky as fatigue behind the wheel.
While caffeine can keep motorists alert, too much of it may do the opposite: impairing focus, slowing reactions, and even increasing the risk of a crash.
Drinking too much coffee is ‘risky’ while driving
Road safety groups are now cautioning drivers against over-relying on caffeine. Study shows that heavy coffee and energy drink consumers are more likely to crash than moderate users.
A 2020 Loughborough University research found lorry drivers who drank large amounts of caffeine reported more accidents and poorer general health.
A newer survey by Carmoola estimated that 11 million UK drivers exceed the recommended 400mg daily caffeine limit, which is the equivalent of about four strong coffees.
NHS GP Dr. Tim Mercer says caffeine, when overused, “can cause restlessness, palpitations and anxiety.” While drinking coffee makes you more alert, too much can overstimulate the nervous system, which creates the illusion of wakefulness and dulls your concentration.
Here's how drinking too much coffee affects your driving:
1. Poor decision-making behind the wheel
Caffeine-induced jitters can cloud judgment and focus. Road Safety GB’s James Gibson warns that drivers “rely on caffeine to fight off tiredness.” But “overdoing it," he says, “can make you restless, anxious, or unfocused." The safest choice you can make is to stop and rest properly.
2. Drinking too much coffee can cause tremors
Drinking too much coffee can overstimulate your nervous system. It can cause trembling hands or legs, making it difficult to steer smoothly or maintain control of your car.
Also Read: How to protect your skin from pollution and smog: Expert tips to prevent damage as AQI rises
3. Slowed reactions as a result of too much caffeine
Excess caffeine intake can lead to overstimulation, which can slow your response time, at a time when quick reflexes are needed.
4. Vision and focus can falter if you drink too much coffee
High caffeine intake, when paired with dehydration, blurs vision, causes twitching, or even rapid blinking, further reducing your awareness.
5. Over-drinking coffee causes withdrawal headaches
Caffeine narrows brain blood vessels. While it eases some headaches, it worsens headaches associated with withdrawal symptoms, which is common after prolonged, heavy intake.
Experts recommend drivers monitor caffeine intake and prioritise rest. “There’s no substitute for proper sleep,” Gibson adds. “Small changes like skipping that late coffee or planning rest stops can make a big difference.”
Moderation, experts say, remains the key, because staying safe on the road is not about more caffeine. It is about more rest.
FAQs
How much caffeine is considered too much for drivers?
Experts recommend staying below 400mg per day, roughly four cups of coffee.
Can drinking coffee make you more alert when tired?
Moderate caffeine helps temporarily, but too much can cause anxiety and poor focus.
Does coffee help sober you up after alcohol?
No. Caffeine only masks fatigue, it does not reduce blood alcohol levels or sober you up.
What is the safest way to stay alert on long drives?
Get proper rest before driving, take breaks, hydrate, and limit caffeine intake.
Note to readers: This article is for informational purposes only and not a substitute for professional medical advice. Always seek the advice of your doctor with any questions about a medical condition.
