How much sleep do I need?

When you sleep, your body goes through 5 different sleep stages in approximately 90-minute cycles. It is around 5-6 of these cycles that make up a good night’s sleep and allow you to feel refreshed. These stages include deep sleep and rapid eye movement sleep (the stage of sleep when you dream). If you wake up in the middle of a 90 minute cycle you can feel quite groggy compared to waking up at the end of a cycle.

The first few 90 minute cycles of sleep are where your body begins repairing as you spend more time in deep sleep. The latter cycles are mind repairing, when you spend more time in rapid eye movement sleep. The mind repairing cycles help with alertness, memory, emotional regulation, and all-around performance. This is why it's important to get a minimum of 5 cycles of continuous sleep to get in those mind-repairing cycles. This works out at around 7 and a half hours as a minimum with 9 hours being even better.

Our advice about how to get to sleep focus on sleep hygiene and these key tips really help:.

• Limit your caffeine intake significantly (ideally to one cup in morning)
• Avoid daytime napping, however tired you may feel (unless driving)
• Exercise in the day, not late in the evening
• Avoid heavy meals before bed
• Shut down any computer screens 1-2 hours before bedtime because of the impact of digital ‘blue light’ on the body’s natural rhythms and melatonin levels.
• Avoid looking at the clock on waking
• Use the bedroom for sleep, not for watching TV or working
• Make sure you have a comfortable bed and bedroom
• Get up at the same time and don’t lie-in.
• Resist the temptation to keep mobile phones or other electronic devices nearby – or if you do, put them on ‘silent’.
• Alcohol can make you fall to sleep quicker, but it actually makes the quality of your sleep worse meaning you may still wake up feeling tired so try to avoid it if possible.

Despite our best efforts, it is sometimes necessary to try to stay awake for longer periods of time than is necessarily healthy. This could be due to working night shifts or that last-minute cram for exams. We would always recommend trying to plan in advance to avoid needing to stay awake more than 15 hours in one go. But, if it is unavoidable, then try some of the following tips.

Natural ways of staying awake include working under bright lights, eating small healthy snacks regularly and by getting up and moving or splashing your face with cold water. Caffeine can also help you stay awake or improve alertness but be careful, as too much caffeine can actually end up hindering your ability to concentrate. Up to 4 cups of coffee or around 600mg of caffeine is the maximum recommended for a positive effect and it is safest to split this across a number of hours. This can be in the form of coffee, caffeine gum, or caffeine tablets. (Be careful with energy drinks as these quite often contain a lot more caffeine than this.)