Nix the Nightcap
Alcohol prevents your body from entering REM sleep (the most restful sleep phase). So, even if you're getting plenty of sleep each night, you may not feel fully rested.
Take a 'Roid Test
If you're tired all the time, you may have a thyroid problem. Other warning signs to look for include weight changes, a hoarse voice, lethargy, and hair loss.
Drink More
Breathing, talking, peeing, even sitting—they all use up the body's water supply. Let your body dry out, and your energy level will dry up as well.
Light Up
Turn on your desk lamp or open the blinds and let in some sun. Your body needs vitamin D (from sunlight) in order to help keep energy levels at their peak.
Have Your BP Checked
Up to 60% of men between 18 and 39 may have high blood pressure, a prime source of chronic fatigue.
Get Your Snack On
Your body needs fuel to run at its peak. Skip even one meal because you "don't have time to eat" (sound familiar?) and your pep will plummet.
Munch on Berries
Doesn't matter what kind, they're all high in energy-boosters called anthocyanins.
Bulk Up Your Diet
Cardiff University researchers found that men with high-fiber diets have less fatigue than men with lower-fiber diets.
Try L-carnitine
The vitamin-like amino acid may help your muscles recuperate more quickly after a hard day at the gym. To feel the jolt, try taking 500 mg a day for at least three weeks.
Get Steamed
According to one U.K. study, up to 68% of men feel more energetic after a hot bath or shower.
Eat More Fish
Studies show the omega-3s in foods like tuna and salmon can help fight depression, leaving you happier and more energized. Don't like fish? Try eating more walnuts and flaxseed, or pop a 1,000 mg fish-oil supplement instead.
Turn It Up
A report in Online Journal of Sport Psychology says that loud music may be one of the most effective tools for relieving stress and fighting fatigue.
Join the B-Team
The American Journal of Clinical Nutrition reports that many athletes and exercise buffs don't get enough B vitamins. That's bad, since thiamin, B6, B12, and riboflavin are all necessary for the body's production of energy.
Limit Lunch to 500 Calories
High-calorie meals take longer to digest and end up pulling energy away from other cells in your body.
Take a Hike
Instead of slamming some candy when the 4 p.m. blahs strike, take a quick walk around the block. Physical activity oxygenates blood cells, helping to refill your body's fuel tank.
Say "Yes" to Yogurt
The good bacteria in yogurt helps keep your intestines healthy, allowing them to absorb more nutrients from the foods you eat. And the more nutrients your cells have at their disposal, the greater your energy reserves.
Avoid trans fats
Foods like doughnuts, crackers, and chips raise levels of bad LDL cholesterol in the body. This narrows blood vessels, blocking the flow of oxygenated, energy-rich blood cells throughout the body.
Opt for whole grains
White bread and pasta spike blood sugar and burn away quickly, sapping energy as they go. Stick with whole-grain foods, which provide longer-lasting fuel.
Don't skip breakfast
Two major studies published in the International Journal of Food Sciences and Nutrition show that breakfast eaters not only feel better mentally and physically compared to people who skip breakfast, but they also tend to have a healthier lifestyle and are better at dealing with depression and emotional stress.
Have a cup of joe
In small doses, caffeine is a great energy booster, increasing mental alertness and even spiking sexual potency.
Just lose it
Whether you're packing an extra five pounds or 50, the further over your ideal weight you are, the less energy you ultimately have.
Go nuts
Almonds and peanuts are so nutrient dense that a single nut packs enough calories to heat up half a cup of water. Nuts are also high in magnesium and fiber, two proven energy boosters.
Get wet
According to a study in the Journal Clinical Neurophysiology, splashing cool water on your face may restore energy even faster than other popular options, like drinking coffee.
Shake it up
The Journal of Applied Physiology reports that men who drink a high-protein shake after working out have more pep than men who refuel on carbs alone.
Clear your sinuses
Men with chronic fatigue are up to nine times more likely to suffer sinus problems than guys who have no problems breathing. An over-the-counter allergy medication may relieve the condition.
Call a buddy
There's more than a decade's worth of research showing that men who open up and talk about their lives with other people have more energy than men who keep their stress inside.
Get it on
In a 10-year-study of 900 men, U.K. scientists found that men who had sex the most often also had the best physical health and most overall energy.
Catch 40 winks
Been sneaking a nap under your desk? Good. The NIH found that power naps boost brain power, preventing burnout and significantly improving mental performance.
Scramble some eggs
Of all foods, eggs are the best provider of energy-boosting protein, according to the American Heart Association.
Swallow Some Calcium
Calcium deficiencies sap muscle strength and lower physical endurance. The average guy needs at least 1,000 mg of calcium a day.
D Up
You need vitamin D to maintain the proper balance of other energy-bolstering vitamins in the body. The best D sources? Fish and D-fortified skim milk.
Get a Massage
Studies show that massage helps you conquer three serious energy drainers—anxiety, headaches, and muscle soreness.
Inflate Your Ego
Try this classic therapy trick: Grab a piece of paper and jot down seven things you like about yourself. Self-confidence equals increased energy.
Wear Brighter Colors
Vibrant greens and blues activate neurons in the brain that keep energy at its peak.
Do a Puzzle
Pick something challenging. Problem solving stimulates brain cells, spiking your body's energy levels.
Do Some Cardio
Biking, running, and swimming all help to increase the number of energy-producing mitochondria in your cells.
Do the Downward Dog
Indian researchers found that men who perform yoga often experience less fatigue during cardiac stress tests than men who don't.
See a Funny Flick
A study in the journal Psychological Reports found that laughter pushes the energy-sapping compound neuroendocrine out of your brain.
Have a Soundtrack
Play background music at your desk. You'll have less anxiety, a prime energy thief.
Get Your Stuff Together
The more organized things are around you, the more mental and physical energy you can devote elsewhere.
Duck Debt
Researches at Ohio State found that men who were stressed over their credit card debt had lower energy levels than guys with less debt or none at all.
Stay Positive
Australian researchers found that men who had positive attitudes suffered fewer injuries and recovered from injuries faster than their darker—less energetic—counterparts.
Sleep In
Getting even one extra hour of sleep a week can counteract most energy-robbing sleep deficits.
Go Out on the Town
Sure it's fun, but studies show that a good social life can also help you feel more energetic.
Vary Your Routine
Switch things around—add intervals to your workout, try new lifts, cross-train. You'll challenge your muscles, furthering their development and giving you more energy.
Relax
Stress is energy's number one enemy. Next time you're swamped, zap the stress by closing your eyes and breathing deeply for 60 seconds.
Schedule a Day Off
Take a day every month to do something fun—no errands and nothing serious or work-related. The happier you are, the better you feel.
Pump Some Iron
Anaerobic exercise—like lifting—boosts levels of three compounds your body needs for quick bursts of activity, ranging from sprints to foreplay.
Veg Out
Load your plate with veggies like tomatoes, carrots, and spinach. The brighter the vegetables' color, the more energy-revitalizing antioxidants they contain.
Chug a Sports Drink
The potent mix of water, sugar, and electrolytes may give you the juice you need to make it through that last set.