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Why Am I So Tired? The 2 Answers That Matter Most

Sleep debt and circadian misalignment are usually why you feel so tired. Find out how to regain your energy for the better.
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Man sitting at desk yawning because he is so tired

A well-stocked energy tank is synonymous with a life well-lived. After all, when you’re brimming with vigor, it’s that much easier (and efficient) to speed through the countless tasks on your to-do list. Unfortunately, many of us feel the opposite. With sleep insufficiency labeled as a “public health epidemic,” one common question takes up residence in our minds, “Why am I so tired?”

The answer may seem complex and even perplexing. For starters, the common causes of fatigue range from not eating a balanced diet to health conditions like iron deficiency anemia and even the dreaded coronavirus. With tiredness being a shareholder in countless diseases, the stakes of feeling run-down can seem perilously high.

That said, the culprits to “Why am I so tired?” are usually non-medical in nature. Instead, you’re most likely dealing with sleep debt and circadian misalignment.

Disclaimer: This post is not intended as medical advice. While the RISE app supports natural sleep patterns and boosts sleep hygiene, it does not treat medical conditions.

The No. 1 Reason Why You Feel So Tired

When you get to the bottom of why you’re so tired, a lack of sleep is usually your guilty admission. Sleep scientists call it “sleep debt,” aka the amount of sleep you’ve missed out in the past 14 days relative to your sleep need.

Not meeting your sleep need usually boils down to these three instigators:

You Don’t Know Your Sleep Need — And Underestimate It

Contrary to popular misconception, not all of us do best on a cookie-cutter sleep need of eight hours per night. Your sleep need is genetically determined and thus unique to you.

For the record, the average sleep need is around 8 hours and 10 minutes (plus or minus 44 minutes or so). A not-so-insignificant percentage of the population (13.5%) may even need 9 hours or more. So, if you’ve clocked in 7.5 hours of sleep last night, chances are you have accrued some sleep debt today.

Time in Bed Doesn’t Equal Time Asleep

Many of us like to think highly of our sleepability skills — nodding off quickly even without being particularly sleep-deprived. But if you tend to take a while to fall asleep, or wake up repeatedly during the night, it’s clear your sleep efficiency isn’t at 100%.

Case in point: Going to bed at 10 p.m. and waking up at 6 a.m. the next day very likely doesn’t translate to a full eight hours of sleep. It’s almost inevitable you spend some time tossing and turning before drifting off and waking up at least once in the middle of the night. Consequently, you don’t meet your sleep need and accumulate sleep debt.

You Don’t Prioritize Sleep (Even When You Should)

Perhaps your new side hustle has you sacrificing your shut-eye in favor of getting more things done. Or your 60-hour workweek makes you burn the midnight oil more often than you want to. Whichever the case, you assume productivity and sleep are mutually exclusive.

What you don’t realize is that you can’t have the former without the latter. On a more insidious note, we tend to subjectively adapt to sleep loss, while objectively, we decline across all the parameters that matter (think cognition, emotions, and health) when our sleep debt mounts.

Why Am I So Tired? Here’s the Other Reason

Not living in accordance with your circadian rhythm (read: your internal clock) is the other reason you’re plagued with daytime sleepiness.

There are a few common scenarios in which circadian misalignment causes you to feel tuckered-out any time outside of your energy dips (i.e., morning sleep inertia, afternoon dip, and evening wind-down):

  • You have a classic case of social jetlag. Similar to travel jet lag, social jetlag is when your social and biological clocks are out of sync. Think back to your late nights out on your days off and early mornings on your workdays. This abrupt change in your internal timekeeping has massive repercussions on your overall well-being.
  • You’re bound to a shift-work schedule. Working outside of the usual 9-to-5 means you’re conscious when your body is primed for sleep and snoozing when it’s daylight outside. Unfortunately, this work schedule turns your body clock topsy-turvy. Predictably, you find it harder to meet your sleep need, further compounding the first issue of sleep debt.
  • You ignore your chronotype. Society is largely attuned to the internal clock of early birds, much to the chagrin of night owls. So, if you have a low sleep debt but still feel “off,” you may be living a lifestyle that doesn’t account for your chronotype.

Other Possible Miscreants Behind Why You’re So Tired

If you’ve consistently met your sleep need and kept yourself circadianally aligned but still feel worn down, there may be other underlying causes of fatigue. Because tiredness is a common symptom across countless ailments and health conditions, it can be difficult to pinpoint the exact issue.

Below, we share the most relevant medical factors that are potential candidates for your fatigue:

  • Sleep disorders, such as obstructive sleep apnea and narcolepsy.
  • Chronic fatigue syndrome, in which you experience extreme fatigue over a prolonged period.
  • Metabolic syndrome, which involves high blood sugar levels, weight gain, high blood pressure, and high cholesterol levels, which increase your risk of medical conditions like type 2 diabetes, heart disease, and stroke.
  • Hypothyroidism (an underactive thyroid gland that doesn’t produce enough thyroid hormone).
  • Kidney disease, in which frequent nighttime urination makes it challenging to meet your sleep need.
  • Fibromyalgia, which you experience widespread body pain, keeping you from a good night’s rest.
  • Rheumatoid arthritis, in which your immune system mistakenly attacks healthy cells and causes joint pain.
  • Mental health problems, like depression and anxiety.
  • Nutritional deficiencies, such as vitamin B12 and vitamin D deficiencies.
  • Coronavirus or even just living through this pandemic. Both the virus and the struggles of these past two years have led to what’s come to be known as COVID-somnia.

Ironically, some medications used for the above health conditions, like antidepressants and antihistamines, incite drowsiness as a side effect.

On a related note, women may feel more tired during that time of the month, when meeting their sleep need becomes more challenging. Plus, dietary factors could be at play, too. For example, those on a weight loss program may feel weaker than usual due to a lower caloric intake.

The Way Forward

The good news is, you don’t have to feel so tired all the time (aside from your energy dips, that is). Pinpoint the root cause(s) behind your persistent fatigue to draw a clear roadmap toward a more energetic you.

If you suspect medical conditions are at work, consult a licensed healthcare professional for a more in-depth diagnosis. For example, your doctor may recommend a blood test to check your red blood cell count and determine if you’re actually anemic. Of course, treatment options will vary according to your diagnosis. To illustrate, a diabetic patient may be asked to do more physical activity and eat fewer carbohydrates. Meanwhile, someone struggling with sleep apnea may need a continuous positive airway pressure (CPAP) machine.

For the most part, though, the culprit is typically non-medical-related. Not enough sleep and circadian misalignment are usually the reasons why your energy levels are in dire straits. Before you down sleep supplements to improve your “sleep quality,” (a term which has no scientific consensus just yet), know that your body already has what it takes to get a good night’s sleep. That’s where the RISE app can help.

Boost Your Overall Wellness With RISE

RISE leverages the two levers of wakefulness — sleep debt and circadian rhythm — to help you feel and function at your best each and every day. Here’s how it works:

It Tells You Your Sleep Need

Remember when we said your sleep need is genetically unique to you? RISE decodes your sleep need by using sleep-science-based models and the past 365 nights of sleep data tracked by your phone to learn your unique sleep biology and calculate your sleep need in hours and minutes.

In the RISE app, tap the right-hand corner account icon on the Sleep screen to find your sleep need.

It Keeps a Close Eye on Your Sleep Debt

RISE app screenshot showing how much sleep debt you have
The RISE app shows your running sleep debt on the Sleep screen — anything more than five hours is probably why you feel so tired.

Every night, RISE uses phone motion-based sleep detection to measure how much sleep you’ve had based on your sleep and wake times passively in the background, without needing input from you. Weighing this data against your sleep need shows the exact amount of sleep debt you’re carrying on the Sleep screen.

As long as your sleep debt exceeds five hours, you are in the red of sleep deprivation. While the jury is still out on whether you can pay back chronic sleep deprivation (after being sleep-deficient for months and years), you most certainly can atone for acute sleep debt and reverse its ill effects. So, if you want to feel and function at your best, it’s definitely worth your while to prioritize paying down your sleep debt.

It Shows You How to Work With Your Circadian Rhythm

While it isn’t normal to feel so tired all the time, it’s absolutely natural for your energy levels to dip at specific times of the day. With that said, the times that those dips occur are unique to you. RISE helps take the guesswork out of when your energy fluctuations occur, as it shows the exact timing of your daily energy peaks and dips on the Energy screen. This way, you know when to push yourself hard and when to slow down.

To feel maximally productive throughout the day (even whilst paying down sleep debt), we recommend tackling challenging work and other obligations, say, a client meeting, during your peaks. Meanwhile, you can relegate tasks that require less brainpower to your dips. For more tips on how to structure your day that benefits you most, check out our Sleep Guide.

It’s Time To Regain Control of Your Energy Levels

For the most part, the question, “Why am I so tired?” doesn’t justify a health scare. Instead, it’s more likely a case of sleep debt and/or circadian misalignment.

Understanding the exact reasons behind each miscreant gives you the tools to arrest their repercussions on your daily life. Of course, willpower is part of the equation when it comes to building healthy habits that will get you closer to your peak performance. Still, there are times when we run low on willpower, which is where RISE comes in handy.

The app, which includes 16 science-based habits to build, leverages cutting-edge behavioral science to help you stick to your new habits with greater ease. It’s the only tool you need to keep you accountable to good sleep hygiene and meet your sleep need, essentially helping you forge a sleep-promoting routine tailored to your unique chronobiology. Download the RISE app today if you want better sleep for better days.

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About Rise
Rise is the only app that unlocks the real-world benefits of better sleep.

Instead of just promising a better night, we use 100 years of sleep science to help you pay down sleep debt and take advantage of your circadian rhythm to be your best.

Over the past decade, we've helped professional athletes, startups, and Fortune 500s improve their sleep to measurably win more in the real-world scenarios that matter most.

Rise Science is backed by True Ventures, Freestyle Capital, and High Alpha; investors behind category winners Fitbit, Peloton, and Salesforce Marketing Cloud.
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