We’ve all been there. Whether it’s first thing in the morning or coming up against that mid-afternoon wall, there are times when fatigue hits us like a truck. Some folks have medical reasons for their lethargy, such as iron deficiency or hyperthyroidism. But for most of us, we’re simply overworked or under-slept.

If you experience regular fatigue during the day, shoring up your sleep shortcomings is a great place to start. Only 20 percent of American adults are getting adequate shuteye, according to an American Psychological Association survey. That means 80 percent need to pry their eyes open to read these tips on how to cut through the fog.

1. Take a (Really, Really) Deep Breath

Short breaths inhibit the lungs from exhaling fully. That leads to a poor exchange of carbon dioxide and oxygen in the bloodstream. Taking a few deep breaths infuses your cells with oxygen, which helps relax the muscles, calm the nerves, and boost mental clarity.

Inhaling deeply through the nose and exhaling through the mouth can even improve your memory, say researchers from Northwestern University. This rhythm helps activate the area of the brain where memory is processed.

2. Straighten Your Spine

Slouching is the default pose for the sleepy-headed, but a study published in Health Psychology revealed that how you sit at your desk can affect your mood and energy levels. Individuals who sit upright reported feeling happier, more energized, and more productive than their hunched over colleagues.

In addition, sitting up straight increases rate of speech and reduces self-focus. It may even get you promoted: A study from Colorado College found that male students with the best sitting posture had better test scores than those who slouched. Also note: This tip is a great one to partner with deep breathing—good posture helps open up your lungs.

3. Drink in the Morning

Fatigue can sometimes be a sign of dehydration. The majority of your bodily fluids, including your blood, are made of water. The slightest sign of dehydration can cause the blood to thicken and push the heart to pump harder. Start the morning by downing a large glass of water and keep sipping throughout the day.

4. Take a Cold Shower

And if you can’t shower at work, a splash of cold water on your face or submerging your hands in a sink—the chillier, the better—should do the trick. Researchers at the University of Chicago found that participants in an experiment who exposed parts of their body to ice-cold water performed better on a standard alertness test than those who only took hits of warm water. The scientists theorize that the pick-me-up comes via a shot of noradrenaline, an energizing hormone that is often released when we experience shock or stress.

5. Make Yourself Move

You may feel more like falling down a flight of stairs than taking one, but numerous studies show that getting physical can lift your energy levels. And you don’t have to break much of a sweat: University of Georgia researchers found that even low-intensity exercise like yoga or walking can reinvigorate exhausted individuals.