My wife, Amy, suggested I write about sleep because she thinks I am sleep deprived. While she “needs” eight hours of sleep, I get by with less and awaken before the newspaper is delivered, which she finds crazy. To some degree, the amount of sleep we need varies, based upon our age and sex. And our waking/sleeping patterns are affected by our chronobiology (the “morning person” or the “night owl”). Of course, these basic requirements have been rerouted by our 24/7 hectic lifestyles. And the fact is that sleep research still has a long way to go before we can say what is best. Let’s look at sleep, primarily from what happens when we do not get enough.
Sleep deprivation occurs when either you do not sleep during certain periods or you get shorter than optimal sleep time. This is contrasted with sleep deficiency (i.e., insomnia), which may occur for a variety of reasons, from health-related to situational, and may contribute to sleep deprivation. Although most adults can tolerate 24 hours of wakefulness reasonably well, you will begin to decompensate physically, mentally and emotionally the longer you’re awake.
As I mentioned earlier, there are many unknowns. Culturally, our sleep patterns have changed significantly as our environments have become artificially lit and most jobs occur during the day. When these factors are eliminated, people often revert to more fragmented sleep-awake patterns throughout the 24-hour period and use the amount of ambient light as a cue.
Researchers still are not sure why we actually need to sleep. Theories include its ability to be restorative, it is needed for growth and development, it assists in memory consolidation, and it is an energy conserving adaptation. What is known is the amount of sleep that is needed changes as we age, from 12-15 hours as toddlers to 6-8 as adults. While six hours is the tolerated minimum, the majority of people believe they need eight hours of sleep. People who sleep for 6.5-7.5 hours have been noted to have the lowest mortality rates. If a pattern of lost sleep is maintained for a few days, work performance and symptoms begin to occur. When this routine is maintained for a period of a few weeks, however, the body begins to accommodate and functioning improves, although individuals may feel drowsy.
It’s not surprising that sleep patterns are superimposed on our circadian rhythms. The body’s ability to regulate temperature is finely tuned to maintain the core within a degree or so of 37° C. The coolest time in this narrow window happens between 3-5 am, and the peak occurs between 2-8 pm. Blood pressure and heart rates reach their nadir during the coolest point, and then gradually increase during the day as our bodies prepare for the day. Performing fine motor tasks and complex mental functioning are better in the morning; short-term memory is also better. Conversely, reaction time is fastest in the late afternoon. Muscle strength, peak and mean power output, and performance at a fixed level of intensity for a few minutes (e.g., intervals) are all better in the late day. For example, swimmers have demonstrated peak muscle output at 6 pm. We’re also more efficient at cooling off later in the day than in the morning, but our body’s already at a higher relative temperature. To not overheat during exercise, mornings are probably better for heavy training and long duration racing, like marathons. Moderate sleep loss does not seem to adversely affect repetitive activities, like endurance runs, while those requiring more fine motor skills, concentration and decision-making suffer.
Optimally, at least six hours of sleep should occur before the low point in body temperature. If not, sleep deprivation may start, with symptoms including:
- Easily distracted and inability to concentrate
- Increased forgetfulness
- Increased reaction time
- Difficulties with memorizing new information
- Increased frequency of mistakes and omissions
- Higher perceived level of stress
- Increased irritability
- Decreased work effectiveness
- Lack of motivation
- Vision – blurriness, dimmed and tunnel
- Auditory – no changes until ~72 hours
- Olfactory – diminished
- Diminished fine and eventually gross motor skills
If you’re like me, you may have checked all of the above. And maybe it’s not surprising, considering we often attempt to do way too much. Over the past few months, I’ve started to step back from some of the many obligations I found myself dealing with – and go figure, I’m actually finding I’m sleeping better and my symptom list is decreasing.
So if you find the above checklist hitting close to home, consider sleep a possible cause. If you’re going 24/7, then give yourself some down time – the world won’t collapse. Here are a few tips to improve your sleep.
- Consider your sleep environment – dark and quiet are best.
- Establish a bedtime routine to quiet your body and mind.
- Keep to a lights out and awakening schedule.
- Avoid eating and drinking alcohol and caffeine a few hours beforehand.
- Don’t read or watch TV in bed.
- Exercise regularly.
By Bob Lutz