Little things can exhaust you both mentally and physically, which can make getting through your day a chore. Here, on Fox News channel, experts reveal common bad habits that can make you feel tired, plus simple lifestyle tweaks that will put the pep back in your step.

You skip exercise when you're tired

Skipping your workout to save energy actually works against you. In a University of Georgia study, sedentary but otherwise healthy adults who began exercising lightly three days a week for as little as 20 minutes at a time reported feeling less fatigued and more energized after six weeks. Regular exercise boosts strength and endurance, helps make your cardiovascular system run more efficiently.

You don't drink enough water

Being even slightly dehydrated takes a toll on energy levels, said Amy Goodson, RD, a dietitian for Texas Health Ben Hogan Sports Medicine. Dehydration causes a reduction in blood volume, explains Goodson, which makes the blood thicker. This requires your heart to pump less efficiently, reducing the speed at which oxygen and nutrients reach your muscles and organs.

You're not consuming enough iron

An iron deficiency can leave you feeling sluggish, irritable, weak, and unable to focus.

Boost your iron intake to reduce your risk of anemia: load up on lean beef, kidney beans, tofu, eggs (including the yolk), dark green leafy vegetables, nuts, and peanut butter, and pair them with foods high in vitamin C (vitamin C improves iron absorption when eaten together), suggests Goodson. Note: an iron deficiency may be due to an underlying health problem, so if you're experiencing these symptoms of iron deficiency, you should visit your doc.

You're a perfectionist

Striving to be perfect—which, let's face it, is impossible—makes you work much harder and longer than necessary, said Irene S. Levine, a professor of psychiatry at the New York University School of Medicine.

"You set goals that are so unrealistic that they are difficult or impossible to achieve, and in the end, there is no sense of self-satisfaction."

You make mountains out of molehills

If you assume that you're about to get fired when your boss calls you into an unexpected meeting, or you're too afraid to ride your bike because you worry you'll get into an accident, then you're guilty of "catastrophizing," or expecting that the worst-case scenario will always occur. This anxiety can paralyze you and make you mentally exhausted, Levine said. When you catch yourself having these thoughts, take a deep breath and ask yourself how likely it is that the worst really will happen.

You skip breakfast

The food you eat fuels your body, and when you sleep, your body continues using what you consumed at dinner the night before to keep your blood pumping and oxygen flowing. So, when you wake up in the morning, you need to refuel with breakfast. Skip it, and you'll feel sluggish.

You live on junk food

Foods loaded with sugar and simple carbs (like the ones you'll find in a box or at the drive-thru window) rank high on the glycemic index (GI), an indicator of how rapidly carbohydrates increase blood sugar. Constant blood sugar spikes followed by sharp drops cause fatigue over the course of the day, Goodson said.

You have trouble saying 'no'

People-pleasing often comes at the expense of your own energy and happiness. To make matters worse, it can make you resentful and angry over time. Train yourself to say 'no' out loud, suggests Susan Albers, a licensed clinical psychologist with Cleveland Clinic.

You have a messy office

A cluttered desk mentally exhausts you by restricting your ability to focus and limits your brain's ability to process information, according to a Princeton University study.

You work through vacation

Unplugging and allowing yourself to truly unwind allows your mind and body to rejuvenate and return to the office stronger.

You have a glass of wine (or two) before bed

Alcohol initially depresses the central nervous system, producing a sedative effect, said Dr. Allen Towfigh, medical director of New York Neurology & Sleep Medicine, P.C., in New York City. "But it ultimately sabotages sleep maintenance."

You check e-mails at bedtime

The glaring light of a tablet, smartphone, or your computer's backlit screen can throw off your body's natural circadian rhythm by suppressing melatonin, a hormone that helps regulate sleep and wake cycles, Towfigh said. Sensitivity to the digital glow of tech toys can vary from person to person, but in general it's a good idea to avoid all technology for one to two hours before bedtime, he said. Can't avoid checking your device before your head hits the pillow? Then hold it at least 14 inches away from your face.

You rely on caffeine to get through the day

Starting your morning with a java jolt is no big deal—in fact, studies show that up to three daily cups of coffee is good for you—but using caffeine improperly can seriously disrupt your sleep-wake cycle, Towfigh said. Caffeine blocks adenosine, the byproduct of active cells that drives you to sleep as it accumulates, he explains. A study published in the Journal of Clinical Sleep Medicine revealed that consuming caffeine even six hours prior to bedtime affects sleep.

You stay up late on weekends

Burning the midnight oil on Saturday night and then sleeping in Sunday morning leads to difficulty falling asleep Sunday night—and a sleep-deprived Monday morning, Towfigh said.