You probably think you know why you’re tired. Long workdays, stress, maybe too much coffee? Sure. Those might be part of it. Thing is, there’s a whole bunch of sneaky little habits that are quietly siphoning away your energy without you even realizing it. Some of them feel harmless, even productive. Others seem totally unrelated to how you feel. I think the most frustrating part is that these energy drains can be happening right under your nose, disguised as normal daily routines. Let’s be real, figuring out which habits are robbing you blind is the first step to actually feeling awake and alert again. So let’s dive in.
1. Skimping on Sleep or Getting Poor Quality Rest
Recent research from 2025 found that just after one full day without sleep, healthy adults experienced significant decreases in attention, increased reaction times, and reduced focus. Shorter sleep durations of fewer than seven hours are associated with higher mortality rates. Sleep deprivation impairs attention and working memory first and foremost, but it also affects other functions such as long-term memory and decision-making. What’s interesting is that many of us think we can get by on five or six hours, convincing ourselves we’ve adapted to it.
The reality is different. Even partial sleep deprivation can have a significant impact on mood, with studies showing subjects reported increased sleepiness, fatigue, confusion, and tension. Without enough sleep, neurons in the brain become overworked, impairing thinking, slowing physical reactions, and leaving people feeling emotionally drained. Sleep isn’t negotiable, honestly. Your brain desperately needs those solid hours to recharge and process everything from your day.
2. Trying to Do Everything at Once (Multitasking)
Multitasking is almost always a misnomer, as the human mind and brain lack the architecture to perform two or more tasks simultaneously, so when we attempt to multitask, we are usually switching between one task and another. Research found that task switching might cost up to roughly half of a person’s productive time due to the cognitive load of moving between tasks.
Rapid task switching places heavy demands on brain networks responsible for focus and control, leading to slower performance, increased errors, and mental fatigue. Every time you shift from checking email to writing a report to answering a message, your brain has to reorient itself. We lack the energy to do two things at once effectively, and trying it means you will do each task less well than if you had given each one your full attention and executed them sequentially.
3. Constant Worrying and Mental Overload
Overthinking is exhausting in ways that physical labor never could be. Chronic mental stress can contribute to muscle tension, headaches, sleep disturbance, and fatigue. Overthinking often triggers hypervigilance, causing us to constantly scan for potential threats, and this heightened state of alert can disrupt daily life, harm personal relationships, and lead to increased anxiety and mental fatigue.
The brain consumes more energy when stuck in a loop of unresolved thought, leading to burnout. Mental exhaustion that anxiety sufferers experience is mainly due to the overthinking of their condition, caused by continually trying to find a solution to how they feel through using their thinking process. Basically, your mind is running marathons while you’re sitting still, and it takes a serious toll. Some days you haven’t done anything physically demanding, yet you feel completely drained. That’s your brain working overtime with worry.
4. Eating Poorly or Skipping Meals
When you skip breakfast or go hours without eating, your body doesn’t have the fuel it needs to function properly. Blood sugar levels drop, and with them, so does your energy. Irregular eating patterns and diets loaded with refined sugars create a nasty cycle of spikes and crashes. You get a quick burst followed by an even harder slump.
The foods you choose matter just as much as when you eat them. Empty calories from junk food might fill you up temporarily, but they don’t provide sustained energy. Your body needs a balance of protein, complex carbohydrates, and healthy fats to maintain steady energy throughout the day. Without that balance, you’re essentially running on fumes and wondering why you can’t keep up.
5. Not Drinking Enough Water
Problems with cognitive performance that can occur with mild dehydration include poor concentration, increased reaction time, and short-term memory problems, as well as moodiness and anxiety. Studies have shown that cognitive function declines at mild water loss of around two percent body water loss, with effects including poorer concentration, increased reaction times, short-term memory issues, and negative mood changes.
Data showed a clear and consistent mood worsening during mild dehydration, mainly characterized by sleepiness complaints and a significant impairment of well-being. Even slight dehydration makes everything harder. One explanation is that individuals compensate for dehydration at both the neural and behavioral levels through investing greater effort and mental energy, thus producing no net performance changes. You might be working twice as hard just to maintain normal function, which obviously drains you faster.
6. Sitting Too Much Throughout the Day
In women who were not meeting physical activity recommendations, those who were less sedentary had significantly lower levels of fatigue than their more sedentary peers. Sedentary people who regularly complain of fatigue can increase their energy levels by around one fifth and decrease their fatigue by nearly two thirds by engaging in regular, low intensity exercise.
Low energy levels are a warning sign of being too sedentary, as when you don’t move enough, your metabolism and blood circulation slow down because inactive muscles have less demand. Physical inactivity can lead to fatigue and low energy because when we don’t move our bodies, our muscles become weaker, and our blood circulation slows down, meaning less oxygen and nutrients reach our cells, making us feel tired and drained. It sounds backwards, but moving more actually gives you more energy, not less.
7. Staring at Screens Before Bed
Blue light from phones, tablets, and computers interferes with your body’s natural production of melatonin, the hormone that tells your brain it’s time to sleep. When you scroll through social media or binge-watch shows right before bed, you’re essentially telling your brain to stay awake. The result is delayed sleep onset and lower quality rest, even if you do eventually fall asleep.
Late-night screen time disrupts your circadian rhythm, which can lead to chronic tiredness during the day. You might be in bed for eight hours but not getting restorative sleep, so you wake up feeling like you barely slept at all. Honestly, putting the phone down an hour before bed can make a bigger difference than you’d expect.
8. Making Too Many Small Decisions All Day
Every single choice you make throughout the day, no matter how small, uses up a bit of your mental energy. Should I wear this or that? What should I eat for lunch? Which task should I tackle first? This phenomenon is known as decision fatigue. By the time evening rolls around, you might feel completely wiped out, even if your day wasn’t particularly stressful.
Decision fatigue quietly drains your cognitive resources faster than you might expect. The constant stream of minor choices adds up, leaving you with less mental bandwidth for things that actually matter. This is why successful people often simplify their routines, wearing similar clothes or eating the same breakfast every day. Fewer decisions mean more energy saved for what counts.
9. Overdoing It on Sugar and Caffeine
That afternoon coffee or sugary snack might give you a quick lift, but it’s a short-lived solution. Caffeine can boost alertness temporarily, but it also impacts your sleep quality later on, especially if consumed in the afternoon or evening. Sugar causes rapid spikes in blood glucose followed by equally rapid crashes, leaving you feeling more exhausted than before.
While these substances may seem like energy boosters, they often contribute to greater overall fatigue. Relying on them creates a vicious cycle where you need more and more just to feel normal. The crashes get worse, your sleep suffers, and your baseline energy drops. Cutting back might feel tough at first, but it often leads to more stable and sustained energy throughout the day.
10. Saying Yes to Everyone Except Yourself
People-pleasing is an energy vampire. When you constantly prioritize others’ needs over your own, you’re left with little fuel for yourself. Always being the one who volunteers, who can’t say no, who bends over backward to help everyone else means you’re neglecting your own rest, interests, and emotional reserves. It’s emotionally exhausting to maintain that level of selflessness.
Boundary issues drain emotional energy in ways that are hard to quantify but impossible to ignore. You might feel resentful, overwhelmed, or just completely depleted. Setting boundaries isn’t selfish; it’s necessary for maintaining your own well-being. Learning to say no, even occasionally, can free up energy you didn’t know you were wasting. You can’t pour from an empty cup, right?
