Is there such a thing as the “right” amount of sleep? What’s normal,and what signifies that we have a problem? As with so much about sleep research, the answers are not easy to give. What’s normal, acceptable and restorative for you might for me seem excessive or too little. Age, genetics, health, the season, and the amount of racked-up sleep debt all help determine the number of hours of sleep each of us needs. And because no two of us are the same, nor are our sleep needs. In 2009 a company in Massachusetts launched the Zeo (see box, p.202), a personalized sleep monitor that tells you how much light, deep and dreaming sleep you’ve had each night. For sleep researchers the Zeo is invaluable because it’s enabled us to see what an “average” night’s sleep is like over a large cross-section of the population (albeit people willing and able to buy the gadget, which at the time of publication is available for between $100 and $200).
The readings from almost ten thousand Zeo participants tell us that the average American sleeps 6.8 hours a night, with six percent clocking up fewer than six hours of sleep a night and 12 percent having eight hours or more. So, does that mean that around seven hours sleep a night is what we should aim for? Perhaps. In order to provide guidelines, experts have agreed that healthy adults need between seven and nine hours sleep. Teenagers need one to two hours more a night; and newborns under two months old should sleep between 12 and 18 hours in every
24. The sleep needs of people aged 65 and over naturally decrease, although there is much speculation as to why, including the consideration that certain medications may disrupt sleep.
As ever, this information is relevant only in light of your uniqueness. Although seven hours might suit your partner, you might need closer to nine. In this book, I’ve assumed that you’re aiming to sleep for eight hours a night, but do adjust my advice in light of your own needs.
too much and too little sleep
The dangers of having too little sleep, and the conditions associated with too little sleep, are well-publicized, but less well known are the adverse effects and associations of too much sleep. The lists below clearly set out the effects of both. Notice hat some of the effects are the same in both categories. Effects of or associated with too little sleep:
• Poor concentration, memory and vigilance
• Sleepiness, tiredness, fatigue, irritability, weariness
• Increased risk-taking, suggestibility
• Poor immune health
• Increased risk of diabetes and morbidity
• Increased mortality
Effects of or associated with too much sleep
• Back pain
You and Your Sleepiness
Sleepiness is a basic “physiological needs” state. You might compare it to feeling hungry or thirsty. In a different way to hunger and thirst,though, the less good-quality sleep you have, the greater your sleepiness, not only when you’re about to go to bed, but at other times, too. How sleepy you feel over the course of the day will depend upon all sorts of factors, including your general health, your age and what’s going on around you. If you’re stimulated and distracted, it can (up to a point) be quite easy to cast aside sleepiness and work through it. If you’re bored or doing something monotonous, sleepiness is harder to ignore. The elderly often feel sleepy between two and three o’clock in the afternoon, our “natural” siesta; while young adults, commuting from work on their way home, often report feeling sleepy as they drive. In this respect, sleepiness is dangerous – but not only for your safety while driving a car. It can also affect your critical thinking and memory.
There are three main factors that affect daytime sleepiness:
• The duration of your nighttime sleep (how long you’ve slept
during the night).
• The quality of your nighttime sleep (how well you’ve slept).
• The circadian time (the time of day).
Measuring sleepiness In 1990, Dr Murray Johns, the founder of the Sleep Disorders Unit at Epworth Hospital in Melbourne, Australia, devised the “Epworth Sleepiness Scale” (ESS) in order to assess the daytime situations in which clients at his sleep clinic were most likely to feel an overwhelming desire to nod off. He asked his clients to score eight potentially sleep-inducing scenarios on a rising scale of zero to three – with zero indicating that the client wouldn’t feel sleepy in that situation and three indicating that the client would almost certainly nod off.
The scenarios Dr Johns gave were: sitting reading; watching TV; sitting inactive in a public place; being a passenger in a car for an hour without a break; lying down to rest in the afternoon; sitting
talking; sitting quietly after an alcohol-free lunch; and driving, but being stopped for a few minutes in traffic. If his patients scored nine or more, he took that to be a good indicator that they might in fact have a sleep disorder. He assessed that healthy sleepers scored around five. Measuring fatigue If the ESS measures general levels of sleepiness, the Fatigue Severity Scale (FSS), developed by Dr Lauren Krupp of New York State University, estimates levels of weariness. Initially created to assess fatigue in patients with multiple sclerosis and the auto-immune condition lupus, the scale is now used to assess likelihood of a sleep disorder. Patients are asked to rate statements relating to how fatigued they feel in certain situations. For example, on a rising scale of one to seven for each, do you feel that fatigue interferes with: your family and work time? Your sustained physical functioning? Your general functioning? And your ability to carry out your responsibilities? Similarly, is fatigue brought on by exercise? Does it affect your levels of motivation? And does it force you to shorten periods of activity? Totting up your score for each, a total of twenty or more suggests you need totake action.
There are lots of online resources that enable you to take the ESS or the FSS, or tests like them. Or, alternatively you can simply score your responses to the scenarios as I’ve given them here. Over the course of this book, I’ll show you ways in which you can considerably improve those scores, which itself means that you’ll have improved the quality of your sleep.
Sound Asleep – Click to read the entire book. Copyrighted excerpts reprinted with permission by author and publisher.
Continue reading – Information on Sleep – Sound Asleep
Continue Reading – The Science of Sleep – Sound Asleep
Author: Dr. Chris Idzikowski BSc, PhD, CPsychol FBPsS
Dr Chris Idzikowski is currently Director of the Sleep Assessment and Advisory Service.. His previous appointments include Centre Director of the Edinburgh Sleep Centre (Heriot Row), Visiting Professor, University of Surrey, Deputy Head of the Human Psychopharmacology Research Unit at the Robens Institute of Health and Safety, University of Surrey and Head of Clinical Pharmacology at the Janssen Research Foundation. He started researching into sleep more than 20 years ago when he worked at Prof Ian Oswald’s sleep laboratory at Edinburgh University’s Department of Psychiatry before researching into fear and anxiety at the Medical Research (MRC)’s Council APU in Cambridge.
An expert on sleep and its disorders, Dr Idzikowski has served as Chairman of the British Sleep Society, and has sat on the boards of the Sleep Medicine Research Foundation, the European Sleep Research Society and the U.S Sleep Research Society. Formerly Chairman of the Royal Society of Medicine Forum on sleep and its disorders (now the Sleep Medicine Section) , he has held many honorary appointments, both health authority (Oxford) and University (e.g Queen’s University of Belfast).