Exhaustion from kindergarten to college has taught us the value of a nap. Yet, 30 percent of American adults suffer from sleep deprivation, and get six hours or less a day. There are different types of naps and nap lengths that could reinvigorate us from a poor night's sleep, and even boost our productivity.

Naps provide a cozier and much comfortable alternative than drinking a cup of coffee or taking a walk outside. Daytime naps can improve our alertness and performance levels whether we're at school or work. Previous research has found naps affect emotion regulation, such as our mood and how we react to things. Researchers at the University of Michigan found after waking from a 60-minute midday nap, people were less impulsive, and had a higher tolerance for frustration.

Read More: Studies Show Afternoon Naps Help Improve Emotional Health, Memory

The benefits of getting a good amount of sleep are irrefutable, but too much sleep can also be hazardous to our health.

A 2016 study in Endocrine Abstracts found taking long naps, or being excessively tired throughout the day, is linked with a higher risk of developing metabolic syndrome. Dr. Adam Splaver, a cardiologist in South Florida, warns against napping for extended periods of time. "Supersize your nap and you may increase your risk for metabolic syndrome by 50 percent," he told Medical Daily.

So, what type of nap is best for us and how long should we nap? Here are three different types of naps. 

Planned Napping/Preparatory Nap

Like its name suggests, this type of nap is "scheduled" in advance of being tired later. For example, if we're going to a late movie showing, we may want to take a nap in advance so we won't be as sleepy. The National Sleep Foundation (NSF) considers this a clever mechanism that will ward off getting tired earlier.

Emergency Napping

If we're struggling to keep our eyes open during the day, the NSF suggests doing an impromptu or "emergency" nap. This type of nap is often used to prevent drowsy driving or fatigue while operating heavy and dangerous machinery. A quick nap can help reduce the risk of injuries and accidents linked to sleep deprivation.

Habitual Napping

A habitual nap is "planned" to take place at the same time every day, typically after lunch or after getting home from work. Kids in kindergarten tend to have habitual naps where they fall asleep around the same time each afternoon. Taking a short nap can sharpen mental acuity and give the body some much needed rest.

Now that we know the different types of naps, how long we decide to nap is contingent on how productive we want to be. Here are four different types of nap lengths. 

Read More: Resting Can Help Reduce Stress And Protect Immune System

The Power Nap (10 To 20 Minutes)

This nap length, commonly referred to as "the power nap," is ideal to boost focus and productivity. A 2012 study in the journal Sleep found 10-minute naps produced immediate improvements in sleep latency, sleepiness, fatigue, vigor, and cognitive performance. The 20-minute nap led to improvements 35 minutes after napping, lasting up to 125 minutes.

The 30-Minute Nap

A half hour nap will bring us to stage II sleep, where we'll reach deep sleep after the first 30 minutes. Stopping at the 30-minute mark will prevent us from feeling groggy, or interfering with nighttime sleep, according to the NSF. A 2015 study in The Journal of Clinical Endocrinology & Metabolism found sleeping up to 30 minutes can reverse the hormonal impact of a poor night's sleep.

The 60-Minute Nap

Sleeping more than 30 minutes but less than 90 can increase the risk of waking up with sleep inertia, a hangover-like groggy feeling that subsides half an hour later. However, a 60-minute nap can helps us feel refreshed and rejuvenated. This nap is known for improvement in remembering facts, faces, and names, boosting our alertness for up to 10 hours.

The Refresher (90-Minute Nap)

Napping for more than 90 minutes goes through every sleep stage, such as REM and deep, slow-wave sleep, which helps to clear the mind, improve memory recall, and restore lost sleep. Naps that include a full cycle of sleep will help limit sleep inertia, and make it easier for us to wake up. This should not replace our 7 to 8 hours of sleep per night.

Splaver suggests if we  need to take a power nap (40 minutes or less) during the day and we can still sleep at night, then power off. This will let us sleep easier, and prevent sleep deprivation.

After all, we all want to be sleeping beauties.

See Also:

Take An Afternoon Snooze To Stay Sharp

Taking A Midday Nap May Help Lower Your Blood Pressure, Stave Off Future Heart Attacks