Why Do I Feel Sleepy During the Day? Here are Some Reasons!

Student sleeping in computer lab
Photo: Graphic Stock

Have you ever experienced a situation where you feel tired in the middle of the day even after getting enough sleep? If this is happening regularly and it does not appear to be due to obvious external situations (e.g. athletic workout, long day at the office, stress, etc.), then other circumstances would need to be looked at.  There are many reasons why people may feel sleepy and worn out during the day. Here are many of the reasons.

Sleep Apnea

Obstructive sleep apnea syndrome concept vector illustration.
Obstructive sleep apnea syndrome concept vector illustration. iStock

A common ailment among many people and a good percentage don’t even know they have it, sleep apnea is a sleep disorder that occurs when a person’s breathing is interrupted during sleep. When this happens, there could be a loss of oxygen in the brain.

In addition, it can increase the chances of high blood pressure, heart disease, and stroke, not to mention the dangers of driving or handling machinery when you are not 100% awake.

There are treatments for sleep apnea. The most common is the CPAP machine. A bulky, noisy mask that you put over your face while you sleep, but there are also dental devices that can work just as well, and the latest technology is where a small device is inserted near your heart.

How is Your Heart?

Human heart, 3d rendering, medically accurate illustration of the human heart anatomy
 with venous system

Several heart conditions can lead to fatigue and affect your energy levels. If your heart becomes weaker, it will try harder to pump the blood. The result is a reduction in oxygen to your organs, leaving you feeling tired even after minimal activity. 

If your fatigue is related to your heart, here are some of the common ailments that you may have:

    • Coronary Artery Disease (CAD): Blocked or narrowed arteries restrict blood flow to the heart, hampering this organ’s ability to function normally. This can lead to chest pain (angina) and fatigue, especially during physical exertion.
    • Arrhythmias: This refers to Irregular rhythms in your heart which can disrupt the normal flow of blood, depriving your body of necessary oxygen and nutrients, subsequently causing fatigue and possibly, dizziness.
    • Congestive Heart Failure: Has your doctor ever looked at your ankles during your visit for a check-up? The reason is that he/she is checking to see if they are not swollen, which could be a sign of a heart defect. Congestive heart failure refers to the build-up of fluid in your lungs and lower limbs if your heart is not pumping blood properly, which can lead to shortness of breath and swollen legs, and consequently, this additional strain on your body can exacerbate fatigue.
    • Valvular Heart Disease: This is different from having clogged arteries. It refers to leaky heart valves that can cause blood to flow back into the chambers of the heart which increases pressure and leads to fluid build-up and tiredness.
Graph of a heart rate
Heart Rate Vector Design Element. Bigstock

In general, the severity of your fatigue, if it is related to your heart can vary, depending on the specific heart condition you may have and how long the condition has progressed. Some people may experience general tiredness during the day, while others may feel sluggish after minimal activity. The condition can also worsen with exertion, emotional stress, or certain medications.

If you suspect your fatigue is related to a heart condition, it’s crucial to seek medical attention as soon as possible. Early diagnosis and proper management can significantly improve your health and subsequent energy levels.

Additionally, lifestyle changes like a healthy diet, regular exercise, adequate sleep, and stress management can help to combat fatigue and improve your overall well-being.

Is important to emphasize that persistent fatigue should not be ignored, especially if accompanied by other symptoms like chest pain, shortness of breath, or swelling.

Summary: There are constant advances in the study of heart health, but the bottom line is you should always consult a doctor who can help determine the cause and guide you toward appropriate treatment to boost your energy and address any underlying heart concerns.

Excessive Salt Intake and Disrupted Acid-Base Balance

Salt on a set of spoons
Sea salt. Bigstock

Your heart health is related to the food you eat and salt can be a major culprit. Excessive use of salt is often associated with the development of cardiovascular conditions.  

Salt can also disrupt the acid-base equilibrium in the body, which scientists consider one of the reasons behind one’s sluggish disposition.

Processed and junk foods are inherently rich in salt because it enhances and preserve the taste. The majority of people today rely on these bad food choices to replete their calorie count. Therefore, it has become more common to not feel fresh even after sleeping for enough hours.

Cut the junk food from your diet and try to decrease the amount of salt that you put in your home-cooked dishes. Cutting down the excessive amount of salt from your diet is a gradual process. But once you succeed in doing this, you will feel more energetic and productive throughout the day.

Selenium Deficiency

Selenium is one of the micronutrients a human body needs in trace amounts. A person that is not eating a balanced diet might face a selenium deficiency. The trace amounts of selenium in the body are part of various physiological functions. An adequate amount of selenium is responsible for the normal functioning of the thyroid. Selenium is also vital for brain and immune functions.

Scientists have found that a selenium deficiency has a direct link with the feeling of exhaustion and cognitive confusion. A person not taking the recommended amount of selenium through their daily diet can develop this problem of feeling sleepy all the time. Seafood, nuts, beans, and eggs are rich in selenium. So make sure that they remain part of your regular diet for the prevention of selenium deficiency. Selenium supplements are also available in the market but we would recommend you to fulfill your selenium requirements from natural sources.

Zinc Deficiency and Slower Metabolism  

Zinc is another trace mineral that has a more important physiological role than selenium. It takes part as a catalyst in various metabolic reactions. So, the deficiency of zinc can slow down the normal progression of metabolic reactions. A slow metabolic regimen is not just bad for weight management, but it also lowers the energy levels of the affected person, resulting in tiredness. According to the World Health Organization, over one billion people are suffering from zinc deficiency all around the world.

Any person with acute zinc deficiency can experience the condition we are discussing in this article. Meat, dairy products, and legumes are some good sources to get the recommended intake of zinc.  However, don’t go overboard with the use of meat because it can lead to some other problems. Similarly, make sure you use dairy products with minimal fat content.

Weight Gain

Sandwich with measuring tape around it

Gaining a four-pound weight might not sound like a big deal. However, scientists have found out that gaining this kind of weight can instigate the feeling of undefined exhaustion. If you can’t get rid of the atmosphere of tiredness after completing the recommended sleep amount, check your weight.  

Excessive Sugar and Slowed Down Metabolism

It is largely believed that sugar intake restores our energy levels. That’s true. However, excessive sugar intake is counterproductive on the body. The surplus sugar stored in the body converts into acid known for lowering the metabolic rate. In normal circumstances, vitamin B1 neutralizes this sugar-driven acid. But in case of excessive intake, vitamin B1 can’t neutralize all of it. As a result, the person starts feeling low and drowsy.

Excessive Sugar Can also Affect the Quality of Sleep

Spoon spilling sugar onto a cup
Photo by Mathilde Langevin on Unsplash

Some recent studies have suggested that excessive sugar in the bloodstream also increases the back and forth between REM and deep sleep stages. A sleeping duration with so many underlying disruptions doesn’t ensure quality sleep. The affected person thus can feel the lingering feeling of exhaustion even after sleeping for enough hours.

Protein and Amino Acid Deficiency

Protein is one of three basic macronutrients that our body needs to carry out its regular functions. People eating fewer proteins can eventually face their acute deficiency. In such cases, the homeostatic mechanism directs the body to fulfill its protein needs from muscles (muscle fibers are primarily made of proteins).

This protein redistribution within the body also uses metabolic amino acids. The depletion of amino acids in the metabolic subsystem can slow down its rate and that can give rise to the feeling of undefined tiredness.

A Cluttered Space and Overworked Brain

Not every undefined instance of tiredness is the function of physiological processes. Researchers at Princeton University have studied that the human brain is wired to sort everything in a certain order in the subconscious. When the brain perceives visual signals from cluttered and untidy spaces, it takes more time to categorize all the information.

As a result, the brain starts feeling tired even when it has not engaged in any cognitive activity.  This unproductive brain activity is also the reason why many continue to feel tired regardless of the amount of sleep they get.

Regular exercise can also help us in combating the feeling of lethargy. Even 20 minutes of daily exercise can have an energizing effect on the body. Scientists also believe that listening to too much music can create physiological and psychological conditions similar to stress, which can also lead to the development of sleepiness and exhaustion for no apparent reason. All things considered, a healthy diet that takes care of every macro and micronutrient need of the body can help in getting rid of the undefined feeling of exhaustion.


There could be many reasons why you may feel tired. First thing to do is to see your doctor and have he/she run a throughout workup to see where the problem exists. Standard blood tests can help in determining why you are tired. It might not be due to an illness, but regardless, there can be many remedies to help you feel more alive and active again!