How many hours do we need to sleep?

Sleeping is an essential function for the human body. Short-term lack of sleep can lead to mood swings and tiredness. And if maintained over time, sleeping little can provoke serious diseases, such as depression.  

Most people need to sleep about 8 hours a day to be in good health. However, if you ask expert professionals in this field, their answer will probably be different: they say there is no specific number of hours which is ideal for everybody. The figure depends on a person’s habits, pace of life, genetics and, above all, their age. 

Hours of sleep according to your age group 

Each person will need more or less hours of sleep depending on their age group. Dr Carles Gaig, neurologist specialising in sleep disorders at the Hospital Clínic Barcelona, explains how your sleep needs change according to your age group: 

• Newborn babies: Need to sleep 20-22 hours a day.  

• Children and adolescents: Usually sleep 9-10 hours a day. 

• After the age of 18: Sleeping 8 hours a day is usually enough. 

• Adults: 7-8 hours of rest is needed. 

• People over 70: Need 6-7 hours.  

The exception that proves the rule 

However, these general figures are not valid for everyone, as there is a small percentage of people who can sleep less without suffering any repercussions on their health. Dr Carles Gaig points out that "About 3% of the population are endowed with genetics that allow them to sleep 6 or even 5 hours every night without this having any adverse effects on them. They are not tired or sleepy the next day, are no more mentally clumsy and have no long-term effects on their health.”  

However, as Dr Gaig points out, “This is a very low percentage of the population. Most people need to sleep 7 or 8 hours.” What's more, there is a popular belief that successful people usually sleep fewer hours, especially in the business world. In fact, numerous well-known figures boast of this habit. However, experts say that either these people are always exhausted or they are part of that exceptional 3%.  

It must also be remembered that, for some people, the opposite is true. In other words, their genetic predisposition means they need to sleep more than 8 or 9 hours a day so as not to feel tired. However, this too is exceptional.