Sleep is very important for you physical and mental health. Sleeping too little is one of the most prevalent poor health habits of our times. But did you know that sleeping too little or too much may have a negative effect on your memory? Scientists from UCL found that sleeping too little or too much could adversely affect cognitive performance such as visual memory and reaction time.
Scientists analysed data from nearly 400,000 participants from UK Biobank as well as data from the International Genomics of Alzheimer’s Project. To avoid reverse causation and confounding, scientists paid attention to genetic data as well – in previous studies these flaws were serious limitations.
Analysis showed that those people who slept for less than seven hours a day made 5% more errors per each hour less of sleep in a visual memory test. However, sleeping too long also had a negative effect – people who slept for more than nine hours made 9% more errors per each additional hour of sleep.
This is the first study to reliably prove that both too short and too long sleep have a negative impact on person’s cognitive ability. Visual memory and reaction times suffer whether you sleep for too long or not long enough.
Scientists conducted a large Mendelian randomization study to identify cause and effect relations in this phenomenon to be able to reliably tell whether sleep times are the reason for the negative change in people’s cognitive performance. Dr Victoria Garfield, senior author of the study, said: “This is the first time that we were able to assess a person’s lifelong sleep duration in relation to cognitive function, as opposed to only looking at how sleep is linked to these outcomes at only one point in time”.
So what can you take from this study? Well, scientists say that you should follow recommendations of sleeping from 7 to 9 hours per day. In fact, most people already sleep around that time. However, increasingly fast lifestyle dictates that many people are cutting down their sleep time and compensate the lack of sleep with coffee or energy drinks. This is particularly harmful behaviour that should be avoided at all costs. If you want to be healthy and perform well, sleep 7-9 hours per day, eat healthy breakfast and move more.
Unhealthy sleeping habits can have a tremendous effect on one’s health. It is akin to smoking or drinking. Your heart is suffering, you are gaining weight, your memory is not as good as it should be. Although most people with bad sleeping habits do not sleep enough, now we see that sleeping too much can be equally as damaging. Just get into a habit of a fixed bed time and stick to it even on weekends.