By Dr Sarah Myhill MB BS

The body has its own internal clock, which tells us exactly what time of day it is.  It is very common in chronic fatigue syndrome and other illnesses to see this biological clock be upset.  Anybody who has experienced jet lag knows exactly the sort of sensations when ones’ biological clock is out of kilter!  In chronic fatigue syndrome the commonest disturbance seems to be that the biological clock is moved on from ours, so people naturally fall to sleep late at night and naturally wake up late in the morning.  For obvious reasons this is anti-social, but it is likely that loss of a normal circadian rhythm gets in the way of recovery.  One possible reason for this has to do with human growth hormone (  This is produced during the hours of sleep before midnight and is an essential part of normal metabolism.  Even our immune cells are tuned in and are non-active at certain times of the day.

When the normal circadian rhythm is lost, there are things that can be put in place to help re-establish it.

Light.  Our biological clock is set by light.  Electricity gets in the way here!  Our forbearers went to bed when it was dark, simply because it was cold, boring and probably expensive on energy to do otherwise.  Their daily biological clock was reset daily.  They slept longer in the winter as they went into a semi-hibernation state in order to conserve energy when food supply was low.  Conversely during the summer they had shorter sleeping hours and longer working hours in order to store up food and resources to allow them to survive the next winter.  People living on the Equator of course have the same sleep requirement throughout the year, but the further away from the Equator one is, the more obvious is this change from winter to summer.  We have lost respect for those annual rhythms – actually we all need more sleep during the winter than in the summer because we go into a state of semi-hibernation and our behaviour should reflect this.  Many people get into a habit of sleeping shorter hours in the summer and sustain this through the winter artificially with the result that as a nation we are chronically sleep deprived.  The average sleep requirement is for nine hours, but the national average is for 7 ½ hours.  Lack of sleep is a major risk factor for heart disease, cancer and of course chronic fatigue syndrome.

We can use light to help re-establish our biological clock.  We need bright light during the day and this switches off melatonin production and melatonin is of course the sleep hormone.  The best light is full spectrum light and we all prefer to sit in sunshine, next to natural light from windows, or failing that one can use light from a full spectrum light box.

Conversely at night we should use light, or rather darkness, to allow our own endogenous melatonin production to happen.  The only way to do this is to be disciplined about the time at which one goes to bed, otherwise electricity gets in the way for obvious reasons.  I often threaten my patients with cutting off their power supply to their house every night at 9pm, which would certainly help them to restore a more normal circadian rhythm!  It may take some weeks or months for the body to adjust, but this is vital for short and long term health.

The bedroom should be dark for all the above reasons – light pollution is a major problem and blackout curtains may be necessary.

Many of my ME/CFS patients complain of light intolerance and indeed the very sick ones simply do not tolerate light and have to lie in a darkened room.  My guess is that this has to do with energy supply to the brain.  The brain uses up energy in the form of ATP ten times faster than the body does. The most active part of the brain is the retina at the back of the eye – this needs a free supply of energy to function properly.  In chronic fatigue syndrome energy supply is severely limited and my guess is that this explains the many visual symptoms that CFS patients complain of.  It also explains why as we age we often get eye pathologies and this is for two reasons – firstly we get less good at supplying energy because declining mitochondrial function is an inevitable part of the ageing process and secondly because the business of delivering energy generates large numbers of free radicals, which are potentially damaging to the eye (

Broadly speaking proteins and fats have a stimulating effect and fire us up whilst carbohydrates have a soporific effect and calm us down.  Western diets are completely upside down – we tend to eat carbohydrates at breakfast and have our protein meals in the evening. We would function much better if we all ate a good fry up at breakfast in which proteins and fats predominate, mix of the two at lunchtime, but in the evening carbohydrates should predominate over proteins and fats.  There should always be a good supply of fibrous foods since these are fermented in the lower gut by Bacteroides to supply short chain fatty acids. These are an excellent energy source and this is what prevents us from developing hypoglycaemia during the night.  Indeed my guess is that poor energy supply to the brain because of hypoglycaemia or because of low fat diets is the commonest cause of disturbed sleep.

I am not averse to people using caffeine during the day in order to fire themselves up – whilst some people are intolerant or allergic to caffeine, for many it helps to enhance the difference between day and night.  Be mindful that caffeine has a long half life for some people who are slow detoxifiers and should not be taken after 4pm, especially if sleep is an issue.

If all the above interventions are in place then the hormone messengers which control our bio-rhythms and many other aspects of life will also fall into place.  However, as we age our ability to produce hormones decline, furthermore in chronic fatigue syndrome it is very common to find poor levels of hormones.  So there may be a good case for taking judicious amounts of hormones as we age in order to maintain our biological clocks – some of these should be measured, some can be safely given without measuring.

a.    Melatonin – this is a natural sleep hormone, output declines with age, melatonin is an excellent antioxidant and one could argue that everyone over the age of 60 should be taking 1mg – 3mg at night.  Some people need slow release melatonin to carry them through the night.  I often use up to 9mg to improve length of sleep and quality of sleep.
b.    DHEA and cortisol – ideally these should be measured by doing an adrenal stress profile.  However, I suspect that like melatonin, DHEA is an acquired metabolic dyslexia – that is to say as we age we get less good at making this.  There is a good case for using 10mg of DHEA sublingually daily in all people over the age of 60, but if you wanted to be sure measure.  The same may well be true for cortisol, but really we should measure to be sure.  Cortisol is well absorbed through the skin and levels can be corrected or boosted with hydrocortisone cream or ointment.  A normal adrenal gland should put out 20 – 25mg of hydrocortisone daily.  A 1% cream or ointment contains 10mg of hydrocortisone per ml of cream, so 1 – 2ml rubbed onto the skin daily may be helpful.
c.    Thyroid hormones – these must be measured in all cases before considering replacement therapy ( and  There is a synergistic relationship between thyroid and adrenal hormones and correction of thyroid hormones is also an essential part of correcting our circadian rhythm.
d.    Vitamin B12.  A great many of my CFS patients get a clear physical and psychological boost from B12 by injection.  Indeed many comment that if they have their B12 injections at night it stops them sleeping!  I am experimenting with a B12 cream and this may be helpful to use in the mornings since B12 is quite well absorbed through skin – indeed it is better absorbed through skin than through the gut!
e.    Chocolate – chocolate is made up of cocoa mass, sugar and milk.  Cocoa mass is very good for us – it is derived from the cocoa beans and there is everything within a bean necessary to make a whole plant.  Therefore it is rich in micronutrients and antioxidants.  Chocolate has a direct calming effect and for many people it is helpful taken at night.  It does have a mild stimulant effect and some people do not tolerate it at night.  The problem with chocolate is the sugar and dairy content – both these are addictive, more so than the chocolate itself.  So the ideal chocolate wants to be high in cocoa solids and dairy free with minimal sugar content.
f.    Alcohol – this is very damaging to circadian rhythms – although initially it makes one feel sleep and tired and can help us to get off to sleep, it will also produce rebound hypoglycaemia which disturbs sleep.

Dr Sarah Myhill MB BS, Upper Weston, Llangunllo, Knighton, Powys, Wales, UK LD7 1SL  June 2010