Your brain is constantly working. Even when you are relaxing, the brain is still active, doing a thousand things you aren't paying attention to. Just like exercises keep your body fit, you need mental workouts to keep your brain fit.

With the help of a few websites and apps, you can regularly train your brain to keep it at maximum efficiency. From boosting your intelligence to re-energizing it during a break, these tools will help in achieving peak brain power.

1. Simple Habit (Web, Android, iOS): 5-Minute Meditations

The benefits of mindfulness meditation have been significantly covered at this point. It is perhaps the easiest form of meditation for a newcomer, and is accessible even if you don't practice it regularly.

Simple Habit takes mindful meditations and turns them into bite-sized chunks, perfect for when you're taking a break. Its makers like to describe it as a "Spotify for mindfulness", since the app curates 50+ top meditation teachers from around the world. So, you'll find a variety of meditations, like those for engineers, for leaders, for teachers, for difficult conversations, and so on.

Brain Exercises -- Simple Habit

Like most such apps, some exercises are free while others are paid. But largely speaking, you will be able to find something in the free meditation exercises that matches your requirements. And like our favorite meditation app, Stop, Breathe & Think, Simple Habit works on web, Android, and iOS, so you can use it anywhere.

2. Brain Breaks (Web): Body Exercises to Energize Your Brain

When you're doing any activity, your brain starts fatiguing after a while. It's difficult to keep up attention spans and focus. Brain breaks are short mind and body exercises that serve to re-energize the brain for a second wind.

Brain Exercises -- Brain Breaks

Dave Sladkey, a teacher himself, created a series of such brain breaks. These aren't puzzles. The exercises involve things like the "snap wink", where you wink your left eye and snap your right hand's thumb and index finger simultaneously. Then you switch to the other eye and hand. Try switching back and forth as fast as you can.

The exercises are ideal to take a break and relax from your computer, while keeping your brain sharp. Sladkey doesn't update the blog any more, but the archives have plenty of fascinating brain breaks to try out.

3. Brain.fm (Web, iOS): Scientifically Proven Better Than Caffeine

When a brain-training and focus-boosting app says it's better than caffeine, you need to sit up and pay attention. Adam Hewett, co-founder of Brain.fm, has researched the effects of music on brain activity for over a decade. This app is the culmination of those efforts.

Brain.fm asks what type of activity you are doing: focusing, relaxing, or sleeping. It'll start playing music accordingly, based on actual science. The makers recommend headphones for the best experience.

Brain Exercises -- Brain.fm

Brain.fm offers 10 free sessions to try it out, then you'll need to pay $7 per month. Before you start, check the how-to guides to learn how to use it effectively.

4. Brain Pump (Web): Educational Videos, Every Day

Brain Pump is one of my favorite sites on the internet. It has a simple mission, which is executed perfectly daily. Brain Pump collects educational and fun videos online, and categorizes them for you to watch.

These include some popular YouTube artists like Minute Physics and ASAP Science, as well as viral videos from little-known sources. The idea is to expand your knowledge by dedicating a few minutes every day to learning. Categories include psychology, chemistry, space, physics, history, business, technology, math, and more.

Brain Exercises -- Brain Pump

The simple interface makes the website a delight to browse. And if you'd like a daily reminder, it's a worth-it email newsletter to learn something new every day.

5. The Guardian's Crosswords (Web): Fight Memory Loss

One of the best brain-training games is one of the oldest: a crossword puzzle. Studies have found that people who do crossword puzzles regularly are less likely to suffer from memory loss, or delay its onset by up to four years.

Brain Exercises -- Crosswords

The Guardian has made its famous daily crosswords available online for free, complete with its vast archive of puzzles. That's over 14,000 quick crosswords and 27,000 cryptic ones.  You can solve the crosswords online, and they even work well on mobile devices. The Guardian even lets you print the puzzle for good old pen and paper solving. If you need any help, we have some quick tools to solve crossword clues.

Of course, dedicated mobile apps might be better if you're only going to solve them on your phone or tablet. Check out these five free crossword apps for Android, or the best daily crossword iPad apps.

Do You Trust Brain-Training Tech?

Several apps claim that they can make you smarter. We've dived into the neuroscience behind brain-training games, but new ones keep popping up all the time.

Do you trust such brain-training apps and games? Are you okay with using them even if the science doesn't hold, since you expect some benefit out of it? Do you think they can cause any harm?

Image Credits: shockfactor.de/Shutterstock