Human beings spend around a third of their lives sleeping. Many might wonder if we really need that amount of sleep or if it's just a waste of time.

However, the truth is, sleep is essential. It bears grave importance for our physical wellbeing, just like healthy eating or exercising does.

But how much sleep do you really need to function properly? The amount of sleep you need per night is generally determined by your age.

If you are an adult aged over 65, you require approximately seven-eight hours of sleep every night.

If you are aged between 18-64 years, seven-nine hours of sleep every night will keep you healthy and functioning.

The amount of required sleep is different for those under the age of 18.

When you are asleep, your body remains active and rebuilds its capacity. There are many reasons why one should get recommended hours of sleep.

Sleep rebuilds worn out muscles. Deprivation of just one night's sleep can increase negative emotional response by 60 percent, according to experts.

Sleep deprivation may also negatively affect the body's ability to regulate appetite, immune system, metabolism, and body weight.

Your inner biological clock controls metabolism, inflammation, reaction to stress. And the right timing and amount of sleep is what keeps the circadian rhythm or internal clock running.

Good quality of sleep is also important to ensure the best outcome of the time you spend in bed.