Better sleep linked with family tree strength

August 6, 2018, University of Oxford
Credit: CC0 Public Domain

The question of why we sleep has been a longstanding subject of debate, with some theories suggesting that slumber provides respite for the brain, which allows it to filter out insignificant neural connections, build new ones, strengthen memories and even repair itself. However, new Oxford University research has used mathematical approaches to tackle the adaptive significance of sleep, and the findings suggest that sleep has another equally significant purpose—boosting our 'fitness' and future family line reproductive success.

The paper, published in PLOS ONE has used mathematical modelling to investigate the adaptive significance of sleep and assess if it impacts 'fitness' (defined as the number of future children, grandchildren, great grandchildren etc.) and mortality.

The work was led by Jared Field, a postgraduate student in the Oxford Mathematical Institute and Professor Mike Bonsall, Professor of Mathematical Biology in the Department of Zoology. The mathematical formulas allowed the team to compare the 'fitness' success of sleeping and not sleeping under a range of different conditions, such as varying birth and , and environments, including vulnerable and safe environments.

The findings show that in all conditions a sleeping strategy led to greater fitness compared to being constantly active. When birth rates were altered but mortality kept constant, they found that a sleeping strategy achieved a greater fitness than staying active indefinitely. In a safe sleeping it was best to be most active when mortality was lowest, where as in a vulnerable environment the reverse was true.

The only instance when constant activity was found to be as beneficial for reproductive fitness was when birth and rates were constant. However, since organisms do not exist in a constant world this result was deemed insignificant.

Jared Field explains: "Sleep as a behaviour, is in and of itself, valuable. While much research has been done to find vital functions that explain why organisms sleep, our study provides broader ecological reasons applicable to a range of environments and conditions. Our analyses suggests that sleep first evolved simply because activity-inactivity cycles are adaptive in a non-constant world."

"Regardless of the scenario, sleep and periods of inactivity were found to have a more positive impact on fitness than not sleeping."

Mike Bonsall adds: "The application of mathematics to understanding biological systems has far reaching consequences and being able to understand phenomena such as how sleep evolved through a mathematical lens is a fantastic advance."

Now that the team have grasped a logical understanding of the evolution of sleep and the factors that underpin its value, in future work they will further investigate the ecological and demographic factors that make or break the difference between a good, productive sleep pattern and a bad one.

The full paper citation is "The evolution of sleep is inevitable in a periodic world' written by Jared M. Field, Michael B. Bonsall, published in PLOS One.

Explore further: Can weekend sleep make up for the detriments of sleep deprivation during the week?

Related Stories

Waking up to new facts on childhood sleepwalking

July 27, 2018

Children, like adults, need quality sleep in order to function well. But, when a child sleepwalks, parents often worry about how this might impact their child's development and behaviour.

Study reveals what sleep talkers have to say

January 12, 2018

A team of researchers with members from several institutions in France has conducted a study regarding sleep talking and has found that most sleep talking is not only negative in nature, but involves a large amount of swearing. ...

Recommended for you

Custom circuits for living cells

September 24, 2018

A team of Caltech researchers has developed a biological toolkit of proteins that can be assembled together in different ways, like Legos, to program new behaviors in cells. As a proof-of-concept, they designed and constructed ...

Silver fox study reveals genetic clues to social behavior

September 24, 2018

In 1959, Russian scientists began an experiment to breed a population of silver foxes, selecting and breeding foxes that exhibited friendliness toward people. They wanted to know if they could repeat the adaptations for tameness ...

How quinoa plants shed excess salt and thrive in saline soils

September 21, 2018

Barely heard of a couple of years ago, quinoa today is common on European supermarket shelves. The hardy plant thrives even in saline soils. Researchers from the University of Würzburg have now determined how the plant gets ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.