Sleep is one of the most important parts of our daily lives. The seemingly never-ending hustle and bustle of life make sleep feel like a luxury. People hardly get enough sleep. According to Neurology India, 9 per cent of Indians are currently suffering from insomnia whereas 30 per cent experience occasional insomnia.Also Read - Alzheimer's Disease: Even a Night's Disrupted Sleep Can Put You at Increased Risk of Developing The Condition

Sleep is incredibly important for your health. From helping in weight loss to improving concentration, productivity, and reducing the risk of developing diabetes and cardiovascular diseases, sleep does it all for you. It also improves your immune function and reduces the risk of depression. Also Read - Suffering From Sleep Apnea? Your Tongue Size May be Responsible

Many people take enough sleep according to them and yet feel lethargic after being awake. And, some feel extremely energetic even after a few hours of sleep. Do you know why? The answer lies in your sleep cycle. Here, we tell you about different stages of a sleep cycle so that you understand it better and know why you wake up like a zombie sometimes. Also Read - Missouri Woman Falls Asleep While Trying Out a Mattress & Spends the Entire Night at Store

Stage 1

This is the first phase of the sleep cycle during which your heartbeat remains normal and you are almost about to go to sleep. Also known as relaxed wakefulness, stage 1 is characterised by hovering between being awake and closing eyes. At this initial stage, your sleep may get disrupted totally by light, noise, or sound.

Stage 2

You remain in this stage for around 60 per cent of your sleep duration. At this stage, your body temperature starts dropping and brain activity also slows down. During a power nap, you remain in stage 2 of the sleep cycle and then wake up.

Stage 3 and 4

This is one of the most important phases of sleep as your body indulges in growing and repairing the tissues. These stages account for 15 per cent of your sleep. You feel energetic after waking up when you reach these stages of the sleep cycle as your body releases hormones for your proper growth and recovery during stages 3 and 4.

Stage 5

It is also called the rapid eye movement stage and lasts for around 90 minutes. Surprisingly, in the above stages, your brain activity goes down however in this stage it remains extremely active. At this stage, you see dreams mostly related to emotions that you experienced during the day.