Many of us are familiar with the afternoon slump. It comes out of nowhere, hitting us sometime between two and five o’clock in the afternoon—even after a solid night’s rest and high-energy morning. As inconvenient as it may be (particularly during the work week), though, that afternoon slump is totally natural.

It all comes down to our internal body clock (a.k.a circadian rhythm). Basically, our brain is programmed to give us regular periods of rest, explains Julia Blank, M.D., family medicine physician at Providence Saint John’s Health Center in Santa Monica. “There is a natural dip in alertness levels to allow us some rest about 12 hours after our deepest sleep cycle,” she says. “Since our deepest sleep typically happens between one and three o’clock in the morning, this puts the ‘lull’ around two in the afternoon.”

Though this afternoon dip in energy is normal—and even healthy—there are certainly cases in which fatigue indicates something more serious may be going on.

When To Be Concerned About Fatigue

While that afternoon slump is nothing out of the ordinary, experiencing consistent bouts of fatigue and exhaustion throughout other parts of the day surely is.

Three scenarios in which Blank says fatigue indicates a legitimate issue:

• you consistently wake up feeling unrested despite a seemingly good night’s sleep
• your fatigue is so debilitating that completing tasks seems insurmountable (or that completing them requires a lot of recovery)
• you are also experiencing symptoms such as fever, nausea, vomiting, dizziness, or headache

In any of these cases, Blank recommends seeing your doctor to do some investigating.

The Common Culprits Behind Excessive Fatigue

There are a number of health issues that can contribute to intense fatigue.

“Thyroid conditions, sleep apnea, cancer, or heart disease could all be to blame for this exacerbated type of fatigue,” Blank says. That’s why seeing your doctor is so important.

Read More: 8 Possible Reasons Why You’re So Tired All The Time

That said, many lifestyle factors that seem fairly harmless can actually be major contributors to daytime fatigue. After all, the body and brain require regular and sufficient rest, hydration, and fuel to maintain optimal function, Blank says. So, if you’re not experiencing extreme symptoms alongside your fatigue, chances are that your own day-to-day lifestyle is to blame. Lack of sleep, excess stress, poor diet, and a sedentary lifestyle can all contribute.

How To Make Your Daily Routine Fatigue-Proof

If your doctor doesn’t identify any clear medical issues behind your exhaustion and you still feel sleepy all day, it’s time to revamp your routine. Use these six tried-and-true solutions to snap out of it and feel more energized.

1. Stay Hydrated

Water is vital for the efficient functioning of nearly every single process in your body—including regulating body temperature, protecting vital organs, and carrying nutrients and oxygen to your cells. The unsurprising result: One study published in Sleep linked a lack of hydration with feelings of fatigue.

Men and women should drink at least 15.5 and 11.5 cups of water daily, respectively, to keep their bodies hydrated and humming along.

2. Set A Consistent, Healthy Bedtime Routine

While more sleep is important, quality sleep is also key. First, aim for seven or eight hours of sleep each night (as recommended by the National Sleep Foundation). Beyond that, Blank recommends going to sleep (and waking up) at the same time each day—even on weekends and days off from work.

Read More: The One Thing I Started Doing Every Night That Helped Me Sleep Like A Baby

Other must-do’s: Keep television, work, and technology out of the bedroom, Blank says. Ideally, you’ll also turn off electronics an hour or two before bedtime.

3. Stick To Regular Mealtimes, Too

When you eat also has an undeniable impact on your circadian rhythm, affecting your sleep and potentially your energy levels, per research published in Current Biology.

Roger E. Adams, Ph.D., owner of eatrightfitness, recommends keeping a regular eating schedule so you can maintain stable blood sugar levels and prevent fatigue. “When our blood sugar drops and we don’t do something about it (like eat), our body starts to conserve energy and slow down, which can lead to fatigue,” he says. Aim to eat balanced meals or snacks every four or five hours—ideally at the same times each day.

4. Cut Back On Sugar And Processed Foods

Nutrition plays a big role in your energy levels and how you feel throughout the day. “If your diet is too low in complex carbohydrates, you may not be providing enough readily available fuel for your body to convert to energy,” explains Adams. “On the other hand, a diet too high in simple sugars and refined carbohydrates may provide a quick energy boost, but not sustaining energy.”

A major contributor of these fleeting simple carbs: processed foods, which have actually been linked to fatigue by research published in the American Journal of Lifestyle Medicine. “Many processed foods high in flours, sugars, or other easy-to-digest ingredients are designed to empty your stomach quickly,” Adams says. “This can leave you hungry again too soon and cause spikes and drops in blood sugar.”

Adams recommends prioritizing whole fruits and veggies, whole-grain snacks, and other slow-digesting whole foods like dairy, nuts, and eggs.

5. Exercise Regularly

You know the energizing feeling you get after completing a workout? It’s not just coincidence—it’s the result of a surge of feel-good hormones called endorphins.

Read More: 7 Home Workout Mistakes That Mess With Your Fitness Results

What’s more: As long as you don’t exercise too late in the evening, regular exercise can help you sleep better. In fact, one study published in Mental Health and Physical Activity found that people who get at least 150 minutes of exercise each week sleep better and feel more alert during the day.

6. Spend More Time Outdoors

One way to help stimulate our circadian rhythm, which naturally helps our body get into sleep mode, is to spend time outside. “An important part of our circadian rhythm is the dark-light, night-day, or sleep-wake schedule,” says Dr. Ilene Ruhoy, M.D., Ph.D., Gut Council Member for Jetson.

While we often focus on the ‘sleep’ part of that, it’s also important to support the ‘wake’ side of things. Getting outdoors every day—even on days when it’s not sunny—is important to simulate that rhythm, Ruhoy explains.

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