Sleep, Biological Rhythms and Electromagnetic Fields - Part I

3 more parts can be found at the articles section of www.chekconnect.com

Chris Maund - C.H.E.K Level IV

Implications for the Corrective and High Performance Exercise Kinesiologist

ABSTRACT

A review of literature is presented with special reference given to practical techniques that can be used to evaluate individuals in a corrective exercise setting.

Particular attention is paid to sleep dysfunction and possible remedies are suggested. A strong correlation is made between electromagnetic fields and sleep dysfunction. Techniques to assess electromagnetic field exposure are presented and some simple remedies discussed.

Other topics covered include circadian fluctuations in flexibility, strength, endurance sports, use of pharmaceuticals, morning and evening propensity, shift work and jet travel. The implications of these variables for program design are discussed.

It is concluded that the effectiveness of the corrective exercise specialist can be greatly enhanced by comprehension of this subject matter.

INTRODUCTION

The original intention of this review was to examine the key features of human biological rhythms that are important for health care professionals dealing with people in chronic pain. However, it became quite clear as I amassed more information on this topic that sleep behaviour and electromagnetic radiation were closely tied to this topic. On closer examination I realized that each of these areas was worthy of study in its own right, and that the complex interactions among all three provided a much better explanation for some of the symptoms that many of my clients presented with. The aim of this review is to bring together information about sleep, biological rhythms and electromagnetic fields in such a way as to benefit clients’ health.

Human beings are incredibly complex. As corrective exercise specialists, we are often faced with physiological riddles that do not respond to conventional Western medicine. The scientific method has created a situation where highly intelligent, well educated people study a tiny aspect of human function and pursue that same minute area for a lifetime. In following this model, many practitioners have lost sight of the big picture and have created a health care system that does not always understand how to evaluate dysfunction from a holistic standpoint.

By rewarding those who attempt to unravel the mysteries of the human body by studying small aspects in great detail, Western medicine has made pariahs of those who wish to study the entire system. Such individuals are usually obliged to get their information outside the realm of mainstream medicine, where technical inaccuracy, misinformation and partial truths are the order of the day. The resulting dichotomy has medical doctors at one end and alternative health care providers at the other, with very few individuals able to move easily and freely from one end of the spectrum to the other. It is clear that in order to significantly improve the general health of Western populations, the two ends of this dichotomy must be synthesized. Good health is not just an absence of disease but a constantly fluctuating equilibrium affected by a vast number of variables. We desperately need a health care system that is capable of identifying degrees of movement away from this equilibrium rather that just extremes.

What follows is an overview of human biological rhythms, sleep behaviour and electromagnetic radiation as they pertain to human health. I have attempted to draw these three areas together because of the potential such a synthesis has for understanding human dysfunction. All three areas have been studied in detail using the scientific method, but it has been mainly alternative health care providers who have commented on the interactions between these topics. A number of scientific studies have been funded by parties who had vested interests in the results and conclusions. A significant number of alternative health care providers can be criticized for lack of objectivity. Both sides frequently display a degree of disdain for each other’s approach.

This review attempts to fuse the information coming from both ends of the dichotomy and to present practical, noninvasive and natural methods that can be used to evaluate and treat chronic pain and dysfunction. This is the ‘middle ground’ of health care, where very few Western health care providers are operating.
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LIBRARY REVIEW

Biological rhythms are fluctuations of any aspect of human function over the course of time. This is a very broad definition that requires some dissection in order to be of use. To classify biological rhythms it is helpful to consider both frequency and the location of controlling forces.

First, we must classify any given rhythm according to its frequency. For example, under normal conditions, the sleep-wake cycle is a circadian rhythm. This word, first used by Franz Halberg of the University of Minnesota, comes from the Latin ‘circa’ (about) and ‘dies’ (day). A day consists of 24 hours, so a circadian rhythm repeats itself every 24 hours.

It is important not to confuse biological rhythms with biorhythms. The biorhythm system attempts to forecast the future by plotting separate physical, emotional and intellectual rhythms onto one chart. These three biorhythm cycles repeat themselves every 23, 28 and 33 days, respectively (35). The system is designed to predict good and bad days for individuals on the basis of their date of birth; it draws a lot of attention from people wishing to analyze sports stars prior to placing bets on their athletic performances. This system is usually dismissed by mainstream science (61) on the grounds that it does not predict human performance with significantly more accuracy than random chance.

This biorhythm concept is intriguing and may have some legitimacy. The problem is that there are so many other environmental factors influencing human function that only on rare occasions will the effect of these three rhythms be seen in scientific studies. The frequency with which this occurs is probably below the confidence level set by most scientists when they analyze data.

The yearly fluctuation of human body composition is called a circannual rhythm. Douillard (30) states that it is perfectly natural to increase body fat percentage over winter, but this contrasts with the work of Zahorska-Markiewicz and Markiewicz (86) who found higher body fat percentages during the summer. Rhythms with a frequency of more or less than 24 hours are referred to as infradian and ultradian rhythms, respectively (61).

The controlling forces behind any of these rhythms can be classified as exogenous or endogenous. For example, under normal conditions growth hormone is secreted at night during the early stages of sleep (41), but this rhythm is inverted in shift workers who work at night and sleep during the day. Sleep is an external factor affecting growth hormone rhythm. So growth hormone secretion is an exogenous rhythm. Endogenous rhythms, like respiration, are driven by internal mechanisms. Respiration is governed by a group of nerve cells inside the body making up a system referred to by motor learning experts as a central pattern generator (70). The rhythm of respiration can, therefore, be referred to as an endogenous ultradian rhythm. The rhythm is described as ultradian because its period is much less than 24 hours.

Many rhythms have both endogenous and exogenous influences. Human rectal temperature displays a different amplitude when subjects are forced to stay awake for 24 hours in constant light while fed hourly snacks. The endogenous component of this rhythm is what remains after removal of environmental cues, such as the circadian light/dark cycle and usual meal times (48).
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SLEEP

Sleep is one of the most poorly understood areas of human behaviour. Considering that we spend around one third of our lives asleep, this lack of understanding is paradoxical. Summarising the available data, Dement and Vaughan (26) state that 8 hours of sleep per night correlates to longevity. Sleeping longer or shorter than this amount correlates to lower life expectancy, although a causal relationship has not been established. Many individuals claim to get by on much less than 8 hours per night, frequently reporting that they feel great and have no health problems. It is tempting to compare the validity of these subjective feelings with the sentiments expressed by ‘experienced’ weight lifters who have spent years performing behind-the-neck lat pulldowns and stiff-legged deadlifts without any apparent problems.

Individual sleep requirements are unique but some general trends can be identified. Teenagers require much more sleep than adults because of the tremendous changes that are occurring in their bodies. Dement and Vaughan (26) state that 9.5 hours is required for teenagers. This amount is almost impossible to attain, particularly in the United States where school starts much earlier than in other countries. Teenagers tend to feel very alert late at night and typically are unable to function well early in the morning. This phase delay phenomenon, coupled with early school start times, leads to an accumulated sleep debt of around 3 hours per night (18, 26).

A study conducted in Edina, Minnesota, throws some interesting light on this matter (26). School start time was changed from 7.20am to 8.30am, resulting in higher test scores and fewer behavioural problems. From a health point of view, it does not make any sense to drag a phase-delayed teenager out of bed very early in the morning in the name of education or exercise. Such adolescents should be encouraged to exercise later in the day, when they are alert.

A good test that can be used to objectively quantify sleep debt is described below. It measures sleep latency, which is the tendency to fall asleep. It is adapted from Dement and Vaughan (26).

Bear in mind that scores will vary depending on what time of day the test is conducted and by other factors like caffeine or alcohol intake or emotional state. Ideally, this test should be conducted at 10am, 12 noon, 2pm and 4pm and an average figure obtained. It may even be necessary to repeat this process on several days so as to get reliable information.

Sleep latency is affected by what Dement calls Clock Dependent Alerting (CDA). CDA is high early in the morning when we get up and even higher in late afternoon or early evening. However, CDA falls off early in the afternoon, helping to create what is sometimes referred to as the post lunch dip. The score obtained on the sleep latency test is affected by two opposing forces – CDA and homeostatic sleep drive. These two opposing forces constitute what is known as the Opponent-Process Model, that was developed by William Dement and Dale Edgar at the Stanford Sleep Centre (26).

This model helps to explain why some people feel very tired in the morning when they get up and very alert in the late afternoon or early evening. These individuals are typically carrying a large sleep debt around. On waking in the morning, instead of having a very small sleep debt like most of us, they still feel sleepy because the homeostatic sleep drive is telling them to pay off the remainder of their sleep debt. Morning CDA is sufficient to get them out of bed but not strong enough to make them feel alert. CDA is much stronger late in the afternoon from around 4-5pm onwards. This extra alerting is sufficient to override the homeostatic sleep drive created by a large sleep debt. It makes sense to question clients regarding their subjective feelings of alertness during the day and to administer the sleep latency test described above to objectify your findings.

A questionnaire that can be used to assess sleep debt as part of your initial evaluation is reproduced in the Appendix (page 72). I strongly recommend that this questionnaire become a standard part of every client’s evaluation. It is very quick and easy to administer and will help the health care professional to identify one of the most commonly missed dysfunctions of all – sleep debt.

Even though the function of sleep is still being investigated, it is clear that both quality and quantity of sleep are strongly related to health. On going to bed, the first period of sleep is called Non Rapid Eye Movement (NREM). After 70-100 minutes, a transition to a Rapid Eye Movement (REM) phase occurs. The third and fourth parts of the NREM phase are referred to as slow wave sleep because EEG measurements show high amplitude, synchronized waves of 0.5 – 2 Hz (87).

There is strong evidence that the amount of slow wave sleep increases when significant sleep debt is present (25). Since the secretion of growth hormone occurs during slow wave sleep and the first half of a typical night’s sleep is dominated by slow wave sleep, many health care providers divide the night into two parts: 10pm to 2am can be regarded as a physical repair period, while 2am to 6am seems to be a psychic repair period (76). This idea is supported by the fact that REM sleep dominates the latter hours of sleep.

REM sleep is characterized by intense brain activity, no body movement and dreaming. It is also linked to memory and learning functions (42). This information correlates well with traditional Indian Ayurvedic Medicine. Ayurvedic doctors advise their patients to eat their main meal at lunchtime and to enjoy a light snack in the early evening. A large meal near bedtime is not advised because energy has then to be diverted from the normal physical regeneration that occurs during slow wave sleep to digestion. People who habitually eat large meals late at night usually do not feel alert and able to get up at sunrise. This is not surprising given that this kind of behaviour reduces the physical repair process during sleep (29).

It is relatively common in Western society for people to complain that they do not have time to eat during working hours. In addition, ten to twelve-hour-days are becoming a regular feature in the modern workplace. Such schedules frequently lead to the consumption of food and completion of exercise regimens up to midnight. I have personally worked with a professional athlete who trained at 10pm and then went home to eat a large meal before getting to bed at 1am. He would then rise just 5 hours later. Since he had been doing this for a long time, he did not think that this behaviour was in any way unusual. Once I restructured his day so that he could get to bed by 10pm without a large meal inside him, most of his musculoskeletal problems went away.

A thorough examination of daily routine is required in order to detect such behavioural problems. This must be done at the first available opportunity and certainly before therapeutic intervention. Failure to clearly identify dysfunctional daily routines will lead to less than optimal therapeutic results because the correction of such dysfunctional daily routines must be given priority over sports specific conditioning. The adaptation to training is optimized when recovery is maximized. Clearly there is little point designing an intense specific conditioning phase if the fundamental basis for physical recovery (slow wave sleep) is absent.

The post lunch dip (PLD) is often blamed on inappropriate food consumption. There can be little doubt that high glycemic index meals often create a feeling of lethargy as blood sugar drops following consumption (71). However, there is ample evidence that PLD is not purely a nutritional phenomenon (9, 50). There appears to be considerable interindividual variation in the precise timing and intensity of PLD, although most people experience it to some extent (17). Since EEG signals during PLD are similar to those displayed during REM sleep (61), it has been suggested that the drowsiness characterizing PLD may be due to a circasemidian (12 hourly) fluctuation of wakefulness and slow wave sleep (13). Given Dement’s assertion that sleep debt is currently a major undiagnosed epidemic, it seems plausible that most of those individuals who display the greatest PLD probably have significant sleep debts (26).

Many cultures still retain the afternoon nap (28). Ayurvedic doctors advise patients to spend 10-15 minutes lying on their left side after a big lunch to assist digestion and specifically to avoid PLD (30). A number of European countries still have afternoon siesta. Typically, businesses are closed from 12 noon-3pm so that employees can spend lunchtime with their families and have a restorative nap afterwards. This practice ensures that they return to work refreshed, energized and productive.

The PLD phenomenon has implications for the corrective exercise specialist. First, it must be acknowledged that an individual’s level of concentration will be significantly reduced during this period, therefore it is not the best time to teach clients technically demanding stretches or exercises. Second, PLD represents a good opportunity for clients with significant sleep debt to pay off some of that debt by napping (26). Getting one hour’s sleep after lunch every day is an extremely effective way to reduce the size of a large sleep debt. Depending on individual circumstances, this may be the most practical way to reduce sleep debt, but it could also be used as an adjunct to extra sleep at night.

These strategies must be implemented from the outset so that sleep latency and daytime feelings of drowsiness can be ameliorated. Remedies are particularly important for clients who operate machinery or drive while at work. For these individuals the price of accidentally falling asleep can be extremely high. Dement attributes a number of major international disasters directly to sleep deprivation; he also states that on average new parents lose 350 hours of sleep during the first year of their baby’s life. He further states that sleep debt can only be paid off by depositing extra hours of sleep in to the sleep ‘account’ (26).

In order to completely repay a 350-hour sleep debt, long-term commitment must be made to the repayment strategy. It is therefore essential that clients understand why it is so important to address this problem if compliance is to be achieved. Regular reassessment of sleep latency will help to motivate clients to continue repaying their sleep debt.