Get smartphones out of bed: UvA sleep researcher

According to researcher Gerard Kerkhof, Dutch people sleep too little, especially young women. "We have a problem of epidemic proportions." he says. Poor sleepers have more chance of being overweight, have a shorter lifespan and poorer performance. Kerkhof's urgent advice is to stop using smartphones after 21:00 at night. Gerard Kerkhof (66) is a professor emeritus of the University of Amsterdam and is still attached to the MC Haaglanden Sleep Center as a psycho physiologist. He is currently researching sleeping behavior in the Netherlands. Although his research is not complete yet, and will probably only be published in a year's time, he is shocked by the results. Kerkhof has questioned more than 2 thousand Dutch people about their sleep patterns and found that a large part of the participants do not get enough sleep. A significant group also suffer from a sleep disorder. 49.2 percent of young women between 18 and 20 years old suffer from a sleep disorder. About a third (30.4%) of Dutch people do not reach the critical limit of 6 hours of sleep per night. The average Dutchman sleeps about 7 hours per night, while an adult needs 7.5 to 8.5 hours of sleep. Dutch men between the ages of 40 and 50 years sleep the least - an average of 6.5 hours per night. Kerkhof can't say why exactly young women in particular have trouble with sleeping disorders, but he has found substantiated suspicions through research. "It is obvious that hormonal issues are involved. And stress is also an important factor. Also, many young women move too little." The effects are not insignificant. Short term consequences include underachievement, bad moods, sleepiness and difficulty concentrating. Long term consequences are even more dramatic. These can range from an increased risk of cardiovascular disease and obesity to an increased risk of Alzheimer's disease, depression and a shorter lifespan. Kerkhof suspects that the use of a smartphone also plays an important role when it comes to sleeping too little, in both young people and adults. "The blue light of the smartphone causes a shift in your biological clock. Moreover, it is more difficult to fall asleep when you, before going to sleep, are still cognitively stimulated by pressing buttons or reading a nasty email." His urgent advice is to throw smartphones out of the bedroom. "Reserve the bedroom just for sleeping well. Away with the telephone or television in your bed."