3. Lack of Sleep
So you stayed up late to catch up on shows you’ve recorded on DVR?

While this sounds fun in the moment, it significantly can impact concentration significantly the next day. That’s because when you’re tired, it’s tough to focus.

A lack of sleep can lead to forgetfulness and memory loss in general, and studies back this up.

According to a University of California-Berkeley study, researchers found memories may get stuck in the hippocampus -- the part of brain involved in memory forming, organizing and storing -- due to the poor quality of deep, "slow-wave" sleep, which is then overwritten by new memories. Sleep deprivation can cause brain deterioration, which may help explain memory loss in the elderly.

So make it a habit to get enough sleep. Research published in the journal Sleep Health says that young adults and adults need seven to nine hours of sleep. And older adults need eight hours of sleep. In other words, no more late-night DVR if it’s going to get in the way of your precious snooze time. After all, you need to be able to concentrate, right?

4. Mindlessness
Mindlessness is the epitome of a lack of concentration. It’s the state of completely zoning out without having consciousness of what's going on in the moment. And it’s a problem when it comes to focus.

A good example of this is driving somewhere and realizing at the destination point that you have no recollection of the drive itself. You were anything but focused, right? That’s a scary thing.

The opposite of mindlessness is mindfulness. It’s the act of being in the present moment -- and focusing on the task at hand. And it’s one of the most important keys to increased concentration.