Physical exhaustion definition, causes, and symptoms

Over the past few years, the shift to virtual work has meant that many of us can sleep in. We no longer have to rush out the door to beat traffic or catch the next train to our office. Instead, we can eat breakfast in bed. We can even wear our pajama pants at our desks. So why do we still feel so tiredor even physically exhausted, before, during, and after work?

We only become our best selves at work when we are the most awake. To approach our work with high energy levels, we must overcome this physical exhaustion. To get there, we first need to understand its symptoms and causes. Let’s begin by taking a closer look at what physical exhaustion really means. 

What is physical exhaustion?

Physical exhaustion is our body's sensation of extreme, persistent tiredness. It is a type of fatigue that completely drains us. When we are physically exhausted, we lack energy, motivation, focus, and engagement. 

Physical exhaustion is often associated with mental exhaustion and stress. While all three undermine our quality of life and well-being, each is distinct.

Mental exhaustion vs. physical exhaustion

Both mental and physical exhaustion trigger persistent fatigue, but there’s one crucial difference. 

Mental exhaustion occurs when work takes a toll on our heart and soul. Physical exhaustion, however, occurs when our work takes a toll on our physical body. 

We are mentally exhausted when we are emotionally disconnected from work. We perceive our work environment, company culture, or our performance negatively. We feel unhappy, unmotivated, disengaged, and isolated at work.

Physical exhaustion occurs when completing manageable tasks and projects seems impossible. Our tasks are more than tedious and difficult. Doing them effectively and efficiently requires a level of strength, focus, and persistence we no longer have. 

Stress vs. physical exhaustion

Stress is heavily influenced by how we perceive a situation. Physical exhaustion occurs no matter how we view situations. It exists despite our best attempts to approach them positively.

Persistent stress, however, can lead to physical exhaustion due to changes in hormonal activity.

When we are stressed, our hormones epinephrine and cortisol are activated. These hormones are intended to prepare us for dangerous situations. They make us more alert and frightened for our safety. They place us on edge and suspend us with fear.

We drain our energy dwelling on these feelings and working through them. This reduces our attention span and vigor for other activities.

The pressure built up inside of us causes us to experience tiredness, difficulty focusing, and muscle tension.

Now that we know how physical exhaustion differs from stress and mental exhaustion, let’s dive into its causes.  

What causes physical exhaustion?

Physical exhaustion results from mental and biological factors and lifestyle choices. Here’s a breakdown of some of the most common causes:

Emotional causes

Like stress, anxiety can also lead to physical exhaustion. Stress and anxiety are quite similar, but the American Psychological Association makes an important distinction between stress and anxiety. 

External pressures and challenges trigger stress. Examples of external pressures are an urgent project deadline or the unexpected passing of a loved one.

Meanwhile, internal rumination and persistent negative thoughts trigger anxiety. An inner voice that talks you out of trying something brave and bold causes you to minimize yourself and your capacity for greatness.  

Anxiety and stress both cause us to feel defeated, helpless, and overwhelmed. Persistent anxiety and chronic stress can both result in mental exhaustion.

Biological causes

Various physical health conditions contribute to physical exhaustion. Some conditions limit our body’s supply of oxygen to our tissues and muscles. As a result, our tissues and muscles have minimal energy. We become tired more easily. A prevalent example is iron deficiency anemia. 

Others result in extensive muscle and joint pain. In these cases, falling asleep and exercising become difficult. A common example is fibromyalgia. This chronic condition occurs when people are hypersensitive to pain. Their bodies interpret pain in a more extreme way. 

Lung, liver, or kidney disease can also contribute to physical exhaustion. So do seasonal allergies and viral and bacterial infections. 

Medications taken to address these health conditions may have side effects. If physical exhaustion is one of them, it may be helpful to ask your doctor about other treatments. 

Oftentimes we experience fatigue and a weakened immune system at the same time. Fatigue indicates we are low on energy when our immune system needs it most to regain strength. 

Lifestyle choices that can contribute to physical exhaustion

Lifestyle choices include but are not limited to: 

• Poor nutritional habits
• Excessive alcohol consumption close to bedtime
• An unregulated sleep schedule
• Overdoing it at the gym
• Tedious work hours

Let’s take a closer look at each: 

Poor nutritional habits 

Nutritional habits have a high potential for physical exhaustion. Ample research shows our nutrition impacts our muscle mass and movement. Both of these impact our muscle fatigue and tiredness. 

Vitamin deficiency in particular drives physical exhaustion. As an example, vitamin D deficiencies decrease our muscle strength. Calcium deficiencies often result in more brittle bones and impaired muscle movement. 

Certain types of diets can also contribute to physical exhaustion if unregulated. These diets often include low-calorie foods lacking protein and fiber. 

Foods that our bodies digest at slower rates provide energy that lasts longer. High-calorie, protein-packed foods are sustainable energy sources. 

Complete protein sources (comprised of all nine essential amino acids that make up our proteins) provide us with more energy than incomplete protein sources. 

Animal-based foods such as eggs, poultry, and dairy products are complete protein sources. Complete plant-based proteins exist but are more limited. Examples include soy and quinoa.

Fortunately, incomplete plant-based proteins can easily be mixed and matched to provide us with complete protein-packed meals. Grains and beans are complementary proteins that provide us with all nine essential amino acids. So are nuts, seeds, and beans.

Like proteins, carbohydrates high in fiber are sustainable energy sources. One type of carbohydrate has a higher fiber content than the other. 

Simple carbohydrates are sugars often found in processed foods and packaged sweets. Examples include glucose, high-fructose corn syrup, and raw or brown sugar. Our bodies digest these sugars without difficulty and convert them to energy faster. The energy we gain from these foods is short-lived. 

Those of us who eat high-sugar foods in large quantities are more likely to feel fatigued faster. We will often experience sugar crashes, which are sudden and drastic decreases in energy. 

In contrast, complex carbs are higher in fiber and in nutrients. Fiber cannot be digested easily, so it is absorbed and utilized at a slower pace. 

The most common high-fiber carbs are whole grains. Select fruits and vegetables like raspberries, guavas, avocados, and broccoli are also high in fiber. Nuts, beans, and seeds are plant-based proteins high in fiber. 

Excessive alcohol consumption close to bedtime

Alcohol is a sedative that depresses the central nervous system. While it causes people to fall asleep faster, it contributes to lower sleep quality. Oftentimes people do not get enough sleep due to more mid-night wake-ups. 

Research shows our body's level of epinephrine increases several hours after drinking alcohol. Epinephrine is the stress hormone that speeds up our heart rate and awakens our body. 

If our levels of epinephrine rise while we're sleeping, we are less likely to stay asleep. Drinking in unsafe amounts before bedtime on a regular basis leads to more mid-night wake-ups. Frequent sleep interruptions cause us to feel groggy and lethargic in the mornings.

An unregulated sleep schedule 

This means inconsistent times for going to sleep and waking up. 

An unregulated sleep schedule is driven by your sleep hygiene, which is comprised of your bedtime habits. 

These habits are all of the behaviors that influence when you wake up and settle in for a good night’s sleep. Examples include getting up to run at the break of daylight or sleeping in to recover from late night’s social event that went into this morning. 

Your sleep hygiene also incorporates the decisions you make while sleeping, such as your choice to doze off in your quiet, dimly light bedroom instead of your loud living room brightened by a TV. 

The more your sleeping tendencies vary, the more difficult it is to achieve restful sleep in daily life. 

Overdoing it at the gym

Intense aerobic or endurance workouts without breaks or high-energy snacks raise our cortisol levels. If we over-exercise, our cortisol level begins to reach and remain at higher levels. 

Workouts closer to bedtime exacerbate this effect. Our cortisol levels have minimal time to stabilize. We're left lying in bed awake despite our best efforts to fall asleep. 

Our bodies are all unique. Excessive exercise is different for everyone. The general expert recommendation is 30 minutes of moderate to intense exercise five days a week for restful sleep. 

Tedious work hours

Working long days can also result in physical exhaustion. Late-night or early morning shifts with minimal sleep in between can too. 

What are the symptoms of physical exhaustion?

Symptoms of physical exhaustion can be emotional, physical, or behavioral. Let’s take a look at the most common ones. Not all of these occur together.

Emotional symptoms

• Mood fluctuation
• Decrease in enthusiasm and excitement for tasks

Physical symptoms

• Muscle fatigue, aches, tenderness, or soreness

• Unshakable sleepiness
• Delayed reflexes and responses
• Tension headaches 
• Migraines 

Behavioral symptoms

• Lower focus and difficulty concentrating
• Impaired decision making
• Decreased efficiency

Side effects of being physically exhausted 

Side effects of physical exhaustion include:

• Increased irritability
• Lower motivation and drive
• Routine tasks feel tedious, sometimes even impossible, to complete
• Chronic fatigue syndrome is extreme fatigue persisting for 6 months or more and prevents you from engaging in routine tasks like work, walking your pet, or completing a personal hobby
• Higher likelihood to eat and snack due to changes in the hormones ghrelin and leptin. Ghrelin triggers our appetite whereas leptin signals we are full. When we’re deprived of sleep, our levels of ghrelin increase. Our levels of leptin decrease. Too little sleep can lead to unexpected weight gain.

Burnout and physical exhaustion

When mental and or physical exhaustion culminates, we come dangerously close to burnout.

Social psychologist Dr. Christina Maslach defines burnout as our response to persistent stress at work. 

Situational stressors include excessive work hours and job uncertainty. High stress levels at work are also triggered by a lack of autonomy, purpose, and social support. 

Maslach breaks burnout into three dimensions: cynicism, exhaustion, and self-inefficacy. 

Cynicism occurs when we view our work environment and company culture with doubt and pessimism. 

Exhaustion can be mental, physical, or both. It occurs when we hit a breaking point. We transition from feeling unhappy at work on a rough day to feeling physically and emotionally unable to work any day. 

Finally, self-inefficacy is the belief we are not progressing at work. It causes us to believe we are failing to thrive and succeed in our workplace. 

Together, these dimensions result in a lack of motivation, purpose, and investment at work. Fortunately, there are several simple ways to overcome physical exhaustion and to avoid it altogether.

7 ways to overcome physical exhaustion 

1. It’s healthy to eat carbs! We often consider eating "too many" carbs a guaranteed way to gain weight in all the places we're trying to lose it. As mentioned before, carbs differ in levels of fiber and nutrition.

High-fiber, complex carbs are your friend. It's time to incorporate them into meals to keep you up and energized all day long.

Be bold in the kitchen and try new recipes or get creative by making your own. Healthy grain bowls and toasts are all the rage now. What's your favorite type of each?

2. Be intentional with your caffeine consumption. Whether you prefer yours piping hot, cold-brewed, or mixed with the newest plant-based milk, many of us rely on caffeinated drinks to kick-start the day. Problems can arise when we depend on these beverages to keep us awake all day.

Caffeine stimulates our central nervous system. It quickly triggers our sense of alertness. Keeping this alertness from turning into a bad case of jitters can be tricky. How much caffeine is too much? 

The FDA considers 400 mg of caffeine — about 4 or 5 cups of coffee — a safe amount to drink. It classifies 1,200 mg or more as dangerous.

Drinking this amount or more can lead to anxiety, nausea, and high blood pressure. It can also lead to sleep disorders such as insomnia, which is difficulty falling and staying asleep or waking up. 

The concept of drinking 12- to 15-cups of coffee per day may be unrealistic to you. But it's important to keep in mind a single large cup of coffee can contain 470 mg of coffee. 

To drink caffeinated beverages in the way we intend to, it's best to be mindful of how much we drink and when. 

The awakening effects of caffeine take between 6 and 10 hours to fully wear off. To avoid trouble falling and staying asleep because of it, it's best to drink earlier in the day, in safe amounts. 

3. Limit electronic use before bed. The screens on our electronic devices release blue light, which contributes to sleep problems. 

Our brains interpret this enriched, blue light as daylight. They signal our bodies to produce cortisol, the hormone that wakes us up. Our bodies can then also stop producing melatonin, the hormone that activates our sleepiness. 

Blue light’s impact on sleep doesn’t stop here. It also decreases our time spent in slow-wave and rapid-eye-movement (REM) sleep. We experience deeper sleep during these two later phases of our sleep cycle. 

Working from home has made us more dependent on our electronics than ever before. To become experts at limiting our electronic use before bedtime, we can progress in steps. 

Without having to change our bedtime behavior, we can limit our blue light exposure. Shifting to a “dark mode” in your device's settings will lower the screen's brightness. 

You can also download free applications to help regulate your exposure. F.lux software enables you to set your computer screen’s brightness to match the brightness of your room. F.lux also enables you to set a time for your computer screen to shift colors. At this time daily, your screen will adopt an orange tint and limit its release of blue light. 

Switching from activating to calming activities before bed will get you in the right headspace for soundless sleep. Try meditation, mindfulness, and reading calming articles, books, and even cartoons before bed. 

4. Create a (screen-free) sleep routine. The more consistent your sleep patterns are, the more restorative your sleep will be. 

A consistent sleep schedule allows you to experience your circadian clock without interruptions. The CDC defines this clock as the “internally driven 24-hour rhythm” that regulates your alertness and drowsiness.  

Changes in light within the environment control this rhythm. Exposure to natural daylight or blue light will stimulate our alertness. Exposure to dimmer light or no light will stimulate sleepiness.

Going to bed at different times every night will result in inconsistent light exposure and sleep patterns. Your circadian clock will not always come full circle. 

On these nights, you won't enter later phases of your sleep cycle. You're likely to wake up more easily and frequently throughout the night. The morning aftermath will be physical exhaustion.

Dimming your bedroom lights around the same time each night will keep your circadian clock in check. Your brain will know nightfall is approaching and your body will produce melatonin like it's supposed to.

Falling asleep and waking up around the same time every day is easier said than done. We all have our share of early morning meetings, late-night family dinners, or children who refuse to sleep without another bedtime story. 

You can structure your sleeping habits in a series of steps. You can set alarms for waking up, turning in, and mid-day snoozes if you’d like to incorporate power naps into your day.

We can practice falling asleep in the same place. This means sleeping in the same room with a set temperature and level of light exposure. 

Our circadian clock will be less interrupted. Our sleep will be longer and deeper.

5. Kickstart your day with a bit of sunshine. Remember how sunlight signals to your brain and body it’s time to wake up?

It's the perfect way to boost your morning routine with physical activity too. Go for a quick walk or jog with your family member, partner, or beloved pet. 

Venture to your favorite breakfast spot and eat outdoors if your schedule allows. Open your blinds before your first meeting. Let the sunlight flood into your room. 

A little bit of natural light can go a long way in brightening your day. 

6. Get up and get active. Exercising not only wakes us up; it makes us happy to be awake. 

We are energized while exercising. Our muscle contractions are made possible by adenosine triphosphate. This molecule stores and transfers the energy our muscles utilize for movement.

During more intense physical exercise-the sweaty, sticky, smelly kind-our bodies release endorphins. These chemicals are a component of the brain's reward system with a lasting effect of 1 to 2 hours. They allow us to experience pleasure while exercising and afterward. 

Incorporating exercise into your daily routine also helps regulate your circadian clock. Working out in the morning or outside will increase your exposure to sunlight. Your body’s activation of cortisol enables you to become more alert and ready to conquer the day. 

Every person’s body and health conditions are different. There is no one way to work out and wake your body up. Exercising later in the day may work best for you. If so, be sure to leave time between your workout and bedtime to cool and calm down. 

7. Redefine your work performance and productivity. It’s time to restructure the 9 to 5 work schedule.

Our victories in virtual and hybrid work settings prove we don't need to sit at a desk for 8 hours straight to do our jobs well. 

Ask yourself the following:

1. When am I most productive with my work and why?

2. Does the way I do my job contribute to my tiredness? Does my tiredness at work affect my performance?

3. What steps can I take to be my most present self at work?

Why we need to combat physical exhaustion

The shift to remote work at many companies provides us with the opportunity to create personalized work schedules.  

Your work hours may not be currently within your full control, but you can create opportunities to increase your agency on the matter. 

Organize open discussions with your managers and team members around more personalized work schedules.

Set up meetings dedicated to exploring this topic at the organizational level. Ask the questions you asked yourself above to your coworkers. Reflect on them together.

The one-size-fits-all solution to working hours is outdated. 

We deserve to work at times when we are most productive, efficient, and excited to complete our projects. We deserve jobs and careers that not only optimize our mental health but our physical health as well. 

Building company cultures that encourage restorative sleep and combat burnout begins with us taking charge of our physical well-being. Specialists can empower us to navigate this journey with confidence and resilience.

When should you consult a specialist?

If you’re experiencing persistent physical exhaustion, it’s time to consult a health professional or specialist. 

It’s important to address this extreme tiredness before it can turn into burnout. At this point, you face the risk of physical exhaustion ruining your mood, weakening your body on the job, and suppressing your sense of purpose and meaning at work entirely. 

BetterUp’s sleep, nutrition, and peak performance coaches (among others) are here to help. Our specialists provide you with personalized insight tailored to your hopes, concerns, and lifestyle choices for both work and in life. 

Coaching sessions provide you with the opportunity to investigate your current eating, exercise, and sleep habits. They also enable you to see how they contribute to or detract from your personal and professional goals. 

Your coach will empower you to develop realistic, actionable plans to overcome physical exhaustion. You will become your most present self at work and in life over the long term. Most importantly, you will be able to track and celebrate your progress along the way. 

The idea of seeking help may seem difficult, awkward, or uncomfortable. It’s important to note that consulting a specialist is not a sign of weakness or defeat. It’s a sign of strength and courage. 

You’re taking action to ensure your work contributes to your health and happiness. You’re also taking agency over your professional and personal development.