Many men and women are walking around today in an energy-deprived state. For some of those people, it's an issue of not getting enough sleep.

According to this Gallup poll, 40 percent of Americans get less than seven hours on a nightly basis. And according to a study published in the American Journal of Health Promotion, people who slept less than 6.5 hours nightly ended up with higher levels of body fat.

I get it though, getting 7 hours of quality sleep was easier 100 years ago when we didn't have lights beaming at us at every corner and a distracting gadget in our pocket (and of course there's Facebook and Netflix).

But, if you're getting seven hours or more and still feel lethargic throughout the day, there's an issue with your quality of sleep. If you're feeling tired all the time, here are four reasons why.

1. Being too sedentary

Combine today's offices with a computer-dominated world and it's difficult to get adequate movement into your day. The world is becoming more and more built on convenience.

Unless you live in New York City or some other walkable city, odds are you're not close to getting the recommended 10,000 daily steps.

Excessive sitting leads to soreness, stiffness in your joints, back pain, and chronic headaches. All of which combine to decrease your quality of life.

While working out a few times a week is great, there's still too much time sitting in idle. Improving this doesn't mean more workouts or adding more miles to your morning run in the park.

Instead, this means adding small movements and pattern breaks throughout your day. Adding more activity helps by regulating hormonal patterns and can actually help you wake up.

By moving, you're creating energy which will lead to cognitive boosts and improving your mood among other things.

Get started by setting an alarm every hour for a 10- minute standing break. Go for a walk down the hall, stretch, do 10-20 bodyweight squats, work on properly breathing, or walk over to your co-worker and tell some bad jokes.

2. An unbalanced diet

If you're eating a lot of high sugar foods, pretend health foods, and processed foods--then focus on removing these habits before anything else. This alone will vastly improve your sleep.

But, if you're already eating sensibly and feel sluggish during your days, then you most likely have some nutrient deficiencies in your diet.

A couple of leading candidates are selenium, magnesium, potassium, and vitamin D.

3. Your quality of sleep isn't good

The majority of adults need 7-9 hours of sleep on a nightly basis. Yet many find it surprising that they can sleep for 7-9 hours per night and still wake up the next morning feeling lethargic. A big reason for this is due to your sleep cycles not being properly optimized.

A typical sleep cycle is between 75-90 minutes with each one cycling through REM and non-REM sleep plus the other stages in between. Each of these stages serves a purpose with helping your body regenerate and detoxify.

A couple causes of low-quality sleep are stress, poor diet, staying up too late, alcohol, hormonal imbalances, adrenal fatigue, and excessive light exposure at night that suppresses melatonin.

To counter this, a couple solutions include exposing yourself to more sunlight earlier in the morning to help with your stress, cut-off caffeine in the afternoon, establish a curfew for your electronics, read fiction, and journal.

4. Stress

Being busy, ambitious, creating your dream business, or climbing the ranks at your dream job describes a big portion of people. And to no surprise, many of them in the pursuit of creating more profits or chasing the ranks unintentionally sacrifice their sleep in the process through unmanaged stress.

Think about this, most visits to the doctor are stress-related problems (60-80 percent in case you're curious).

Stress becomes problematic because it's going to elevate your cortisol and other stress hormones to levels that they don't need to be. This keeps you in a prolonged "flight or fight" state, which is preventing you from turning off and calming down to get quality rest at night.

A couple of solutions to help with this are meditating, yoga, massage therapy, tai chi, or walks out in nature while disconnecting from your phone.