3 Sneaky Reasons You Wake Up Feeling Tired

Judging by the mounting population of Americans who are interested in sleeping more—and possibly stocking up on—melatonin, and CDC data that suggests 1 in 3 of us are falling short of our seven hours per night, it’s clear that few of us wake feeling chipper, well-rested and totally ready to tackle the day.

Hey, we get it: Amid the bustling holiday season, work, obligations with loved ones, errands, cooking, cleaning and beyond (oh yes, and ideally some exercise and self-care time slotted in there somewhere too), it’s tough to carve out space in the schedule for adequate sleep. But sleeping less than seven to nine hours per night has some serious health consequences. Research suggests that insufficient or low-quality sleep can impact your immunity, heart health, weight, skin, brain and more.

It can also do a number on your energy levels and alertness, making those aforementioned daily activities feel hard. About 45% of Americans confirm that poor sleep or not enough quality sleep affected their daily lives at least once during the last week, according to the National Sleep Foundation.

Of course, getting more and better sleep tonight plays a major role in better energy levels tomorrow. But according to a study published in November 2022 in the journal Nature Communications, a few other modifiable lifestyle factors may impact your alertness levels more than genetics. People who exercise regularly, eat a breakfast with carbohydrates, and maintain a fairly steady blood sugar tend to feel more alert.

Read on to learn more about this sleep study, plus how to set your day up for sleep success—and a bright and productive day after the alarm sounds.

What this sleep study found

For this research, the scientists collected data from 833 adults aged 18 to 65 who enrolled in their two-week study. This included twins as well as unrelated adults so they could estimate the impact of genetics on the results. Each participant wore an accelerometer on their wrist for the full 14 days to track activity levels and sleep, and recorded their food intake and alertness (rated on a scale of 0 to 100 every three hours) on an app throughout the study.

Each person was given a prepared breakfast with the same amount of calories every day of the study, and the menus offered a range of macronutrient compositions, including high-carb, high-protein and high-fiber meals (which were eaten on different days) as well as a “control” meal of moderate protein, carbs and fiber.

The researchers were likely not surprised to discover that those who slept longer than usual or woke up later than their norm felt more alert the next morning. More surprising, though, were the other revelations after crunching the numbers from the two-week info-gathering session. Those who had the following habits reported higher levels of morning alertness:

• Being physically active during the 10 most active hours of the previous day (but not close to bedtime)
• Consuming a higher-carb breakfast that also includes protein and fat
• Having a lower “glycemic load” at the other meals of the day, meaning they were able to maintain a more steady blood sugar

So, that being said, the three sneaky reasons you might be waking up tired (besides not getting enough quality sleep) include:

1. Being sedentary throughout the day
2. Skipping breakfast or avoiding carbs as part of a balanced breakfast
3. Eating in a way that causes your blood sugar levels to spike and crash, rather than staying more consistent

They also discovered that those who reported having an overall more positive mood felt more alert than their more pessimistic peers. Genetic factors appeared to have a very minor impact on alertness levels—far less than activity, sleep and diet.

So what’s the big deal about alertness levels anyway? Earlier studies have linked reduced alertness to less productive days, higher risk for car accidents, hampered judgment, less vigilance, more errors and difficulties with decision-making. Plus it doesn’t feel all that great to walk around dragging all day!

The bottom line

A study determined that a higher-carb yet balanced breakfast, a workout in the morning or afternoon, an overall meal plan that’s fairly low on the glycemic index, and getting enough sleep can all impact alertness levels.

Since this study was based partially on self-reported data, involved a fairly small sample size, only measured certain aspects of the participants’ overall lifestyle and didn’t account for light exposure (a known factor in alertness levels and a detail that’s related to natural melatonin production), more related research is needed to confirm these findings.

Until we know more, if you feel like your energy levels are dragging, it certainly can’t hurt to …

• Add more foods that are lower on the glycemic index to your menu (including whole grains, fruit, nonstarchy vegetables, nuts, beans and legumes).
• Schedule time for a 30-minute walk—or your preferred form of exercise—at any time before dinner.
• Eat a balanced breakfast with a good dose of carbs. A few examples from our roundup of 9 foods dietitians swear by for better sleep:
  • Everything Bagel Avocado Toast sprinkled with pumpkin seeds
  • Steel-Cut Oatmeal (made with milk and honey)
  • Peanut Butter-Banana Cinnamon Toast