We know that low blood sugar can lead to fatigue of the adrenal glands, and that the adrenal glands are the body’s main defence mechanism against stress. It therefore seems likely that those with chronic low blood sugar can suffer a vicious circle of adrenal exhaustion, which causes anxiety, and with the anxiety comes further exhaustion and stress. Unfortunately, many people suffering from stress often overeat or comfort-eat the wrong foods. They also tend to miss meals, relying on caffeine, tobacco and alcohol for their fuel, thus further aggravating any blood sugar imbalance.
Respiratory changes
Surprising as it may seem, low blood sugar can also affect the respiratory system. The reason for this is a substance called histamine. This compound is naturally present in all the cells of the body and has a variety of uses – not least is its role in controlling osmosis (passage of water) between the body membranes. It is well known that if the histamine level increases, the characteristic symptoms can include hay fever, skin rashes and asthma. The link between histamine and the blood sugar exists because histamine and glucose are on separate ends of a seesaw. If the glucose level drops, the histamine level rises and vice versa. It follows that a patient who has low blood sugar may, under certain conditions, also have asthma or hay fever.
It is an interesting fact that diabetic patients rarely develop asthma; there are also very few cases on record of an asthma patient also having diabetes. (The main exception is the condition known as cardiac asthma, which is associated with heart disease). Many asthma patients find to their delight in their late 40s and 50s that their asthma symptoms improve. The reason for this is that they are developing late onset diabetes and their blood sugar has become raised above normal level, thus protecting them from asthma.
It should be said that low blood sugar is not the only cause of asthma; there are certain types of asthma caused by stress or extreme sensitivity to various allergens, vigorous exercise, infections and various irritant particles. A good medical dictionary will list more than 30 different types of asthma, usually defined according to their cause.
Musculo-skeletal changes
The other system of the body that is frequently affected by low blood sugar is the musculo-skeletal system – in other words, the muscles and joints. As already explained, the effect of the adrenal glands and, in particular, Cortisol on joint inflammation is well documented, hence the apparently miraculous symptom-relief afforded to rheumatoid arthritis patients when Cortisol is taken or injected. If the adrenal glands are overworked and fatigued as a result of prolonged low blood sugar, and the efficiency of steroid hormones that protect the joints from inflammation is compromised, joint pain, stiffness and swelling may result. This link between musculo-joint symptoms and stress is known to all of us. The expressions ‘pain in the neck’ or ‘pain in the butt’ illustrate the connection. Whether any adrenal exhaustion is caused by stress alone or indirectly caused by low blood sugar, the resulting joint and muscle symptoms are the same.
General symptoms of low blood sugar – the two stages
STAGE ONE SYMPTOMS – FALLING BLOOD SUGAR
The immediate symptoms that follow a fall in blood sugar result from a reduction in the brain and nervous system fuel (i.e. glucose). These first stage symptoms generally include mental and physical lethargy, partial or total loss of concentration, headaches, trembling and/or dizziness, a tendency to yawn, paleness of lips and face with either a skin coldness or heat with perspiration, unexplained anxiety and a sudden urge for chocolate or anything sweet.
STAGE TWO SYMPTOMS – ADRENAL COMPENSATION
The second stage symptoms are caused by the adrenal response to the low blood sugar level. For many people these symptoms are more distressing than those of the first stage.
The surge of adrenaline that occurs in response to low blood sugar causes symptoms identical to the body’s response to stress. The metabolism is literally revved up for action. The heart rate increases and the blood flow to muscles is stepped up. This can be likened to pulling out the choke on a car to increase the available fuel. Heavy sweating can occur, with breathlessness and unpleasant palpitations.
A frequent consequence of the stress reaction is a degree of irritability or even aggression – a good example being the mood swings of the diabetic patient. Those readers who have a diabetic friend or relative will know only too well that when a ‘hypo’ occurs the victim becomes both irritable and aggressive. Many people with low blood sugar symptoms show a degree of anxiety, irritability or depression – symptoms that often improve as their problem is resolved.
All this is part of our body’s normal reaction to stress. If we are confronted by an angry bull as we cross a field we need to increase our oxygenation, heart rate and muscle strength to hastily flee. Most athletes and competitive sports people know the value of this adrenaline effect, for the power and speed increase it can provide. They learn to control and at times to override the adrenal response to further their sporting goals.
For most of us this alarm-response by our body is in direct proportion to the intensity of the threat or stress. However, many who suffer with chronic low blood sugar lose their fine control and an adrenal hair-trigger response to stress of any kind leads to frequent and often unnecessary alarm-responses. When adrenaline is released on a regular basis for trivial reasons, many distressing symptoms can develop. Some sufferers, for instance, are frequently awakened at 3–4am bathed in sweat, anxious, with a rapid pulse and short of breath. This occurs because the adrenal response to their nocturnal low blood sugar is being inappropriately triggered and their metabolism is stressed.
Unfortunately, even when we sleep changes in the blood sugar can activate the adrenal response. Professor Hans Selye, who wrote the definitive first description of our response to stress in his landmark 1956 book The Stress of Life, described sleep as follows: ‘No one is ever absolutely at rest, while alive. Even during sleep, your heart, your respiratory muscles, your brain continue to work. It makes no difference that you are not conscious of this and that these activities require no voluntary effort on your part’.
Our management of stress is a very individual quality that depends on many factors. The amount and type of activity appropriate to a five-year-old child would be very stressful for a 75-year-old man and vice versa. Our stress load and our stress handling are unique to each of us. Stress can, of course, be on many levels, psychological, chemical, structural or environmental. It does not always need to be unpleasant or unexpected to give rise to symptoms. Enjoyable, planned events can also be stressful – excited children becoming sick at parties and sports people suffering asthma attacks are examples of this.
Trigger factors
The most common triggers that can cause low blood sugar symptoms include one or more of the following:
