“I’m tired all the time.”
“I have no energy.”
“I’m too tired to go to the gym.”
“I need a nap.”
Walking around in a fog seems like standard operating procedure nowadays. No matter how common it is, though, feeling exhausted, low energy, or sleepy all the time is not normal. It’s always a sign that something else is going on.
Tiredness, Sleepiness, Fatigue: What’s the Difference?
What does it mean when someone says, “I’m tired all the time?” Are they falling asleep at their desk? Do they need to take an afternoon nap in order to function in the evening? Perhaps they feel too wiped out to exercise or even get off the couch?
Colloquially, we use the word “tired” to describe the subjective experiences of both sleepiness and fatigue. “Sleepiness” is the familiar experience of needing sleep due to sleep debt. We all know what this feels like.
“Fatigue” can mean a few things. There is the tiredness you experience after overwork or exertion, which is usually temporary. Then there are the chronic feeling of exhaustion, low motivation, physical weakness, or inability to function.
From a medical perspective, sleepiness and fatigue are different. The boundaries are fuzzy, though, and there is a lack of agreement about the best ways to assess and differentiate the two.1 
Sometimes sleepiness or fatigue are easy to explain. You get a few bad night’s sleep in a row. Yesterday’s CrossFit WOD was particularly brutal. An important and stressful work project is wearing you down. Situations like these, in which there is an obvious, short-term cause for your tiredness, are generally not a problem. Assuming you give yourself appropriate rest, you should recover just fine.
Chronic tiredness—whether sleepiness or fatigue—can make it impossible to participate fully in life. Everyday activities such as driving may become dangerous. It interferes with work, physical activity, relationships, and general quality of life.
Persistent tiredness that interferes with day-to-day functioning and quality of life is not normal. In today’s post, I’ll discuss some of the common causes of feeling tired all the time and provide tips for troubleshooting.
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“I’m Sleepy All the Time”
We all need a minimum of seven to nine hours per night. Yet, survey after survey shows that most adults and even many children chronically get less sleep than they need. It’s no surprise that in studies, around 20 percent of the population experiences excessive daytime sleepiness.2 
Obviously, the first question you should ask yourself is, “Am I getting at least seven hours of sleep per night?” Really, I’d say at least eight for most people. That doesn’t mean seven hours in bed. It takes a while to fall asleep, and most people wake up at least a couple times per night. An analysis of over 10 million users’ Fitbit data revealed that the average person is awake or restless for 25.5 minutes per night.3  If you’re aiming for seven hours of sleep, you should be in bed for eight. Want eight? Commit to being in bed for nine.
Here are a few sleep tracking methods to help you understand where you are starting .
What You Can Do to Get Better Sleep
If you believe you’re getting the requisite amount of ZZZs, the next question is whether you are getting it at the right time. Daytime sleepiness can be caused by inconsistent sleep and wake times.4  If you are maintaining one sleep schedule during the week and a completely different one on the weekends, stop. Make a concerted effort to maintain the same sleep and wake times for a few weeks and see if that helps.
Sleepiness is also a sign of circadian rhythm misalignment.5  This is when your sleep doesn’t align with your body’s natural biological clock. Shift workers, who are up at night and asleep during the day, are the classic example, but it need not be so extreme. One theory holds that some of us are “larks” (early to bed, early to rise) while others are “night owls.” Not all sleep experts agree, but it’s worth considering whether your current sleep schedule feels natural to you.
In any case, you should be sleeping when it’s dark and awake when it’s light. If you’re staying up late binge watching shows and struggling to wake up in the morning, that’s the first thing to fix.
Make sure you are practicing good sleep hygiene. That means:
- Proper amount of time in bed
- Appropriate sleep timing
- Minimizing blue light at night
- Cool, dark, uncluttered room
I’ve written often about sleep hygiene. I’ll link to related posts at the bottom.
If you believe that you have all the obvious sleep boxes checked, yet you feel excessively sleepy during the day, talk to your doctor. They can test to see if you are suffering from a sleep disorder. Sleep apnea  is a common one, but there are dozens more.6 
Consider keeping a sleep-wake diary or using a sleep tracker such as an Oura Ring or Fitbit. This can provide some initial insight into what’s going on.
Can Your Diet Cause You to Feel Tired All the Time?
Possibly. There are certainly links between certain vitamin and mineral deficiencies and fatigue. Low iron (even without anemia),7  vitamin D,8  B vitamins (especially B129 ), vitamin C, magnesium, sodium, zinc, L-tryptophan, L-carnitine, coenzyme Q10, and essential fatty acids are among the most commonly implicated.10  Vitamin D in particular seems to be associated with sleep disorders.11 
Food intolerances can also contribute to tiredness. The majority of patients with celiac disease12  and non-celiac gluten sensitivity13  complain of fatigue. Food allergies and intolerances are common among people diagnosed with chronic fatigue syndrome, and supplements are frequently used as part of treatment protocols. If you haven’t already, simply eliminating gluten from your diet for a few weeks is an easy at-home experiment. Even if it doesn’t help your tiredness, I’m willing to bet you’ll see other benefits.
Especially if you’re experiencing other digestive symptoms, you should work with a practitioner who can help determine if you suffer from allergies or intolerances. They should also test for underlying gut issues that might be exacerbating the problem.
If you’re not eating enough food to fuel your daily activities, that can make you feel fatigued as well. Some folks who practice intermittent fasting or follow a keto diet find they accidentally undereat. Ketones can suppress appetite, and when you’re eating in a restricted window, it can be hard to get in enough calories. If this rings a bell, track your food for a few days to make sure your calorie intake is adequate.
Is It What You’re Drinking?
Research shows a correlation between caffeine consumption, daytime sleepiness, and nighttime sleep issues.14 ,15 ,16  Of course, it’s entirely possible that sleepiness leads people to consume more caffeine, not the other way around. Experimental tests on the effects of caffeine consumption are mixed, suggesting individual differences in the degree to which caffeine affects sleep.17 
And then, there’s alcohol, which can cause sleep disturbances.18  It’s counter-intuitive, because a lot of people like to have a glass of wine or other beverage to help them sleep. While it may help you fall asleep, alcohol has a tendency to disrupt sleep phases in a way that renders your sleep incomplete.
On the other hand, maybe it’s what you’re not drinking—enough water. Dehydration, perhaps even mild dehydration, can cause fatigue.19 ,20  You don’t have to force yourself to drink a certain amount each day, but consider adding a glass of water or two, perhaps with a pinch of sea salt, if you’re feeling somewhat fatigued.
Lifestyle Factors That Affect Tiredness
Leading a sedentary, indoor lifestyle
Being sedentary is associated with experiencing greater fatigue.21  It’s hard to get moving when you’re tired, but low-intensity exercise has been repeatedly shown to alleviate fatigue, including in chronic fatigue syndrome.22 ,23 ,24  Exercise can also improve sleep.25 
Taken as a whole, the evidence suggests that low-level aerobic activity is particularly effective for helping to relieve tiredness. If you’re feeling tired all the time, try going for a daily walk. Walking  is by far my favorite low-intensity activity. Plus, you get the added bonus of sun exposure, weather permitting. Get that vitamin D boost! One study found that three-quarters of patients who complained of fatigue were deficient in vitamin D27 , while another showed that supplementing with vitamin D can improve symptoms.28 
Experiencing extreme and/or chronic stress can also lead to fatigue and sleep problems. Mindfulness Based Stress Reduction interventions have been shown in many studies to reduce symptoms of fatigue in individuals with a wide range of chronic health problems.29 ,30 ,31  You can also experiment with supplements in this article that help your body process stress.
Is Your Tiredness a Sign of Underlying Medical Issues?
If you are experiencing fatigue that isn’t obviously related to sleep or lifestyle factors, you should talk to your doctor. There are many underlying medical issues for which fatigue is a noted symptom. Some of the most frequently cited are:
- Anemia32 
- Type 2 diabetes33 ,34 
- Hypothyroid35 , including subclinical hypothyroidism36 
- Heart disease37 ,38 
- Perimenopause and menopause39 
- Depression40 
These are just some of the many issues that are associated with otherwise unexplained sleepiness or fatigue. There are others, namely chronic fatigue syndrome and fibromyalgia, for which fatigue is a defining characteristic, not just a symptom.
When you talk to your doctor, try to be as specific as possible about what you are experiencing. Is it fatigue that manifests as physical exhaustion, weakness, or lack of desire or ability to do daily activities? Persistent sleepiness despite apparently good sleep habits? Make a note of frequency and patterns, such as if you experience fatigue more at certain times of day, after meals, or, if applicable, at specific times of your menstrual cycle. Track your sleep for a few nights at least. Your doctor will ask.
Tell your doctor about any other symptoms you are also experiencing, even if they seem unrelated. Your doctor might spot a pattern that leads to a diagnosis. Finally, make sure you tell your doctor about any medications you are taking, as fatigue might be a side effect.
Getting to the Root of Your Issues
As you see, there are lots of possible causes for tiredness. If your sleepiness or fatigue is significantly affecting your quality of life—you have trouble completing your daily tasks, your memory is impaired, your mood is affected or you feel depressed—a doctor’s visit is absolutely in order.
If you want to try to self-experiment at home first, start with the obvious and easy steps:
- Optimizing sleep hygiene
- Staying in bed for eight to nine hours every night at the same time
- Eliminating gluten if you haven’t already
- Removing caffeine in the afternoon
- Making sure you’re hydrated 
- Avoiding long periods of being sedentary
- Getting outside and getting plenty of sunlight
- Taking steps to alleviate stress 
You can also try tracking your food for a week using Cronometer to see if you are consistently low on any vitamins or minerals. Up your intake of foods rich in the vitamins or minerals you need. If you’re not already eating a serving of liver each week (for iron  and other nutrients) and small, oily fish  (for essential fatty acids) on the regular, do that. If you think you’re clinically deficient in one or more areas, get tested before supplementing willy nilly.
Is Inflammation the Key?
What do poor sleep, chronic illness, sedentary lifestyles, poor gut health, chronic stress, and nutrient-poor diets all have in common? Inflammation .
It’s perhaps no surprise, then, that some scientists believe that inflammation is a key feature in fatigue of various etiologies.41  Luckily for you, everything about the Primal diet and lifestyle is aimed at avoiding the big offenders when it comes to inflammation. Still, if you see your doctor, ask them to test your inflammatory markers.
Don’t let anyone write off your tiredness as normal. Yes, you might be busy or have young children or train for endurance events. We all have a lot of reasons to be “feeling down” right now. Still, you know when something is wrong. You deserve to feel vibrant and energetic.
More from Mark’s Daily Apple
- https://pubmed.ncbi.nlm.nih.gov/20514923 /
- https://www.sleepfoundation.org/sleep-disorders/excessive-sleepiness 
- https://blog.fitbit.com/how-do-your-sleep-habits-stack-up/ 
- https://pubmed.ncbi.nlm.nih.gov/8843535/ 
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4677771/ 
- https://pubmed.ncbi.nlm.nih.gov/25367475/ 
- https://pubmed.ncbi.nlm.nih.gov/28625177/ 
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5207540/ 
- https://www.bmj.com/content/349/bmj.g5226/ 
- https://pubmed.ncbi.nlm.nih.gov/10767667/ 
- https://pubmed.ncbi.nlm.nih.gov/22583560 /
- https://pubmed.ncbi.nlm.nih.gov/12741468/ 
- https://pubmed.ncbi.nlm.nih.gov/24885375 /
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3280075/ 
- https://pubmed.ncbi.nlm.nih.gov/27527212/ 
- https://pubmed.ncbi.nlm.nih.gov/16549311/ 
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6292246 /
- https://www.sciencedirect.com/science/article/abs/pii/S1087079201901625 
- https://www.mayoclinic.org/diseases-conditions/dehydration/symptoms-causes/syc-20354086 
- https://pubmed.ncbi.nlm.nih.gov/26290294/ 
- https://pubmed.ncbi.nlm.nih.gov/23783259/ 
- https://pubmed.ncbi.nlm.nih.gov/18277063/ 
- https://pubmed.ncbi.nlm.nih.gov/27031610/ 
- https://pubmed.ncbi.nlm.nih.gov/27995604/ 
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3317043/ 
- https://bjsm.bmj.com/content/32/2/107 
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4158648/ 
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5207540/ 
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4431452 /
- https://pubmed.ncbi.nlm.nih.gov/26519614/ 
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5187553/ 
- https://www.sciencedirect.com/science/article/abs/pii/S0093775401902076 
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2905388/ 
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6064586/ 
- https://pubmed.ncbi.nlm.nih.gov/22989469/ 
- https://www.aafp.org/afp/1998/0215/p776.html 
- https://pubmed.ncbi.nlm.nih.gov/24589645/ 
- https://pubmed.ncbi.nlm.nih.gov/3169045 /
- https://pubmed.ncbi.nlm.nih.gov/10851573/ 
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3225130 /
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5247454/