If there's one thing that the old saying, "too much of a good thing can be a bad thing" really shouldn't apply to, it's sleep.

Sleep is rejuvenating. Restorative. Essential to your health. A welcome break for both your mind and body.

Surely getting more of it can only be a good thing...

But what about those nights when you actually go to bed early and you sleep like a rock, only to wake up feeling just as groggy as when you go to bed late?

"Oversleeping can come with some unwanted — not to mention counterintuitive — side effects, including daytime sleepiness. But, if you're only doing it here and there, getting more sleep than you need typically isn't harmful to you," says Dr. Aarthi Ram, neurologist specializing in sleep medicine at Houston Methodist. "In some cases, however, regularly oversleeping can be a sign of an underlying health condition."

But what's considered "oversleeping" anyway?

What's considered too much sleep?

"The exact amount of sleep that's best for each person varies, but the average adult typically needs somewhere between seven to nine hours of sleep per night," says Dr. Ram.

And this isn't just some arbitrary range chosen to help fit sleep into our busy lives — it's the sweet spot most people's bodies crave.

"Studies show that, even when visual cues are taken away (day vs. night), people naturally tend to sleep about eight hours a night, give or take a half hour or so," explains Dr. Ram.

So if you need more hours of sleep than usual, well…just don't be surprised if you feel tired the next day.

Why too much sleep makes you tired

Here's the thing: You can keep hitting snooze on your alarm clock, but that doesn't mean you're snoozing your body's internal clock.

"Any deviation in your sleep pattern can disrupt your circadian rhythm, which you can think of as your body's internal clock. This clock is what keeps you on a schedule, timing important biological processes in your body, such as when you're most alert and when you get hungry," explains Dr. Ram.

When your internal clock is thrown off — whether that's because you got less sleep than usual or more — it can disrupt your whole schedule, leaving you feeling fatigued when you'd normally feel alert. It might also affect other things, too, such as your metabolism, energy levels and more.

5 tips to prevent oversleeping

To avoid the effects of oversleeping, take these five steps to prevent it:

1. Know the signs

You might be oversleeping if you:

• Need more than nine hours of sleep to feel well rested
• Are excessively sleepy during the day
• Depend on naps or caffeine to get through the day, even with sufficient sleep
  
  

If these signs sound familiar, you might be getting too much sleep and would benefit from taking steps to prevent oversleeping.

2. Get on a consistent sleep schedule (and stick to it)

Thanks to our internal clocks, we're creatures of habit.

This means that one of the best ways to ensure you get the optimal amount of sleep is to get on a schedule by going to sleep around the same time every night and waking up at a similar time every morning.

"It's particularly important to keep your wake time consistent," says Dr. Ram. "Yes, even on weekends."

3. Avoid the urge to snooze

Some struggle with this more than others, but the impulse to hit the snooze button catches up to all of us now and then.

The most important thing is to be realistic with your alarm time.

If you're a snoozer, you may be tempted to set your alarm way earlier than necessary — to account for all of your snoozing. But this habit may actually leave you feeling less rested than if you simply set your alarm for the time you actually need to wake up.

"The 10 more minutes of sleep you're granting yourself over and over and over isn't productive sleep. You're not going to feel more rested by continuing to snooze your alarm clock. If anything, all of that interrupted sleep will make you feel more groggy," adds Dr. Ram.

Instead, set your alarm for a realistic time and resist the urge to snooze.

If you have trouble with that last bit, there's always the old move-the-alarm-clock-across-the-room trick — which forces you to physically get up to snooze it. By then, it gives you plenty of time to realize that you're up now anyway.

4. Don't just get the right amount of sleep, take steps to get good sleep

Even if you're doing it all correctly — going to bed and waking up around the same time every day, avoiding the snooze button — getting poor sleep might be what's causing you to feel like you need more of it.

"There are several ways to improve your sleep. These healthy steps are often referred to as good sleep hygiene," says Dr. Ram.

You can improve your sleep hygiene by:

• Getting on a consistent sleep schedule
• Giving yourself time to wind down before bed
• Making sure your sleep environment is cool and dark
• Avoiding caffeine, alcohol and screen time before bed
  
  

5. Be careful with sleep medications like melatonin

"Sleep aids — including over-the-counter melatonin — can help you fall or stay asleep, but they can also sometimes make it harder to wake up, particularly if the effects haven't worn off before then," says Dr. Ram.

When is oversleeping a problem?

There are the obvious times when oversleeping is problematic, such as when it makes you late for work or school or when the resulting daytime fatigue affects your ability to concentrate on an important task.

But, then, there are the not-so-obvious times.

"Certain underlying health conditions can contribute to poor sleep, making you feel like you need more hours of sleep to feel fully refreshed," says Dr. Ram.

Health issues that can cause oversleeping include:

• Sleep apnea
• Chronic pain
• Restless leg syndrome
• Grinding your teeth as you sleep
  
  

"Additionally, some medications can lead to poor sleep," adds Dr. Ram. "If you're oversleeping, review your medications with your doctor."

There are also several sleep disorders that impair sleep altogether, such as:

• Narcolespsy
• Hypersomnia
• Delayed sleep phase syndrome
  
  

If you're sleeping more than usual, it's important to consult with your doctor — especially if you've taken steps to prevent oversleeping but haven't seen improvement.

"Your doctor can assess your sleep hygiene and make recommendations to improve it, as well as run the tests needed to rule out whether an underlying condition may be present," says Dr. Ram. "He or she may also refer you to a sleep specialist, who can further evaluate your sleep issues and determine whether a sleep study may be needed."