More than 85% of mammals are polyphasic sleepers, sleeping for short periods throughout the day. Humans are part of the minority as monophasic sleepers, as our days are divided into two distinct periods, one for sleep and one for wakefulness. This may or may not be our natural sleep pattern however, as young children and elderly people generally need to nap and napping is a key custom for many cultures.
A short nap of 20-30 minutes can help to improve mood, alertness and performance but probably won’t make up for a bad night’s sleep.
3 types of nap:
- Planned napping - taking a nap before you feel sleepy. Could be useful if you know you will be having a late night!
- Emergency napping - when you suddenly feel really tired and can’t continue with whatever you are doing. E.g. when you feel drowsy driving or while using heavy and dangerous machinery.
- Habitual napping - when you take a nap at the same time each day. (Often after lunch!)
Top napping tips:
- Duration - a short nap of 20-30 minutes is best to improve short-term alertness without leaving you feeling groggy or interfering with nighttime sleep.
- Sleep environment - make sure that you have a peaceful place to lie down and that the temperature in the room is comfortable. Try to limit the amount of noise heard and the amount of light coming in.
- Timing - If you take a nap too late in the day, it might affect your nighttime sleep patterns and make it difficult to fall asleep at your regular bedtime. If you try to take it too early in the day, your body may not be ready for more sleep.
Benefits of napping:
- To restore alertness, enhance performance and reduce mistakes and accidents. A study at NASA on sleepy military pilots and astronauts found that a 40-minute nap improved performance by 34% and alertness 100%.
- To increase alertness in the period directly following the nap may extend alertness a few hours later in the day.
- Help with narcolepsy, a sleep disorder characterized by excessive sleepiness.
- Psychological benefits - a nap can feel like a mini holiday!
- Reducing drowsy driving - sleep experts recommend that if you feel drowsy when driving you should immediately pull over to a rest area, drink a caffeinated drink and take a 20 minute nap.
- Night shift work can cause fatigue and impair performance - research has shown that a combination of naps and caffeine can help.
Negative effects of napping:
- Sleep inertia - feeling groggy and disorientated. While this will probably only last for a few minutes to half an hour, it can stop you getting back to work effectively.
- Negative effect on other sleep - a long nap or a nap taken too late in the day may adversely affect the length and quality of nighttime sleep.
- One study has indicated that napping is associated with an increased risk of heart failure in people already at risk.