What Not to Do When You're Tired: 10 Critical Mistakes to Avoid

Sleep deprivation is one of the most common problems in the modern world, affecting every aspect of our lives, from physical health to cognitive and emotional functioning. When we’re tired, our bodies and brains don’t operate at their best, and our decision-making can be impaired. Following are things you should avoid when you're feeling fatigued to prevent harm to yourself and others.

1. Driving

One of the most dangerous mistakes people make when tired is continuing to drive despite fatigue. Studies show that exhaustion reduces reaction time, alertness, and focus — similar to the effects of alcohol. In fact, a tired driver can be just as dangerous as a drunk one. If you find it hard to concentrate, your eyelids are heavy, or your head starts to nod, those are clear warning signs. Pull over, rest, or find another way to reach your destination.

2. Making Important Decisions

Fatigue clouds judgment, weakens the ability to weigh pros and cons, and increases impulsiveness. If you need to make significant decisions at work, with your family, or regarding finances, it’s better to wait until you’re more alert. Brain research shows that when we’re tired, we rely more on emotion than logic, which can lead to poor decisions we may regret later.

3. Endless Scrolling on Your Phone or Social Media

One of the worst habits when you're tired — especially before bed — is aimlessly scrolling on your phone. Screens emit blue light that suppresses melatonin production (the sleep hormone), making it harder to fall asleep. Plus, fatigue reduces concentration, making it easier to waste hours scrolling instead of giving your body the rest it needs.

4. Heated Arguments or Emotional Conversations

Lack of sleep heightens emotional sensitivity, making us more irritable and reactive. Fatigue skews our perception, leads to impulsive reactions, and increases the chance of saying things we’ll regret. If you’re feeling tired and tense, postpone difficult conversations until you’re calmer and more self-aware.

5. Drinking Caffeine Late in the Day

Coffee is a temporary fix for fatigue, but drinking it late can disrupt your sleep. Caffeine stays in your system for many hours, so an evening cup can make it harder to fall asleep, creating a vicious cycle of chronic fatigue. If you're tired at night, opt for water, herbal tea, or warm milk instead of stimulants.

6. Impulsive Shopping (Especially Online)

When we’re tired, we become less cautious with our spending. Fatigue leads to impulsive behavior, which can result in unnecessary purchases — especially online, where a single click can cost you. Avoid online shopping when you're tired and wait until you’re more focused to make financial decisions.

7. Unhealthy and Mindless Eating

Tired bodies crave quick energy, making us reach for sugary and carb-heavy foods. Studies show fatigue increases hunger and lowers food quality choices. To prevent overeating or poor nutrition, aim for foods that offer sustained energy such as proteins, fruits, and vegetables, instead of sugary snacks that lead to an energy crash.

8. Performing Complex Tasks That Require Focus

Avoid tackling critical tasks when you're tired. Writing reports, studying for exams, or completing detailed work should be postponed for when you're more alert. Sleep deprivation impairs memory, attention, and concentration, increasing the risk of mistakes.

9. Intense Physical Exercise

Exercise is important, but if you're sleep-deprived, your body may be too weak, and poor coordination can increase the risk of injury. Instead of pushing through a tough workout when exhausted, opt for light activities like a walk, stretching, or yoga.

10. Ignoring the Fatigue and Trying to “Push Through”

One of the worst mistakes is ignoring signs of exhaustion and continuing as if nothing’s wrong. If you don’t listen to your body's need for reset, it can lead to a sudden energy crash, brain fog, or long-term health issues. Take a break, rest, or even just close your eyes for a few minutes to allow your body to recover.

Fatigue isn’t something to overlook. When you feel tired, slow down, give yourself a break, and prioritize healthier habits. Your mind and body will thank you.