Hypoglycemia is a condition in which the blood glucose level is too low – a carbohydrate that is the main source of energy for humans. This condition most often accompanies diabetes – a serious chronic disease in which fluctuations in sugar levels (both increases and decreases) occur permanently.
However, there is also a form of hypoglycemia unrelated to diabetes – reactive hypoglycemia. It is also called postprandial hypoglycemia, which reflects its nature because low blood sugar levels are caused by meals consumed.
The brain uses more than half of the glucose in the blood. Due to the small supply of brain glycogen, the efficient functioning of the central nervous system depends on a continuous supply of glucose. This may explain the presence of the main centers regulating glycemia in the brain during hypoglycemia.
Nerve cells involved in regulating glucose concentration in body fluids are located mainly in areas adjacent to the third and fourth ventricles, where the blood-brain barrier is absent. Since it was experimentally demonstrated that destruction of the ventromedial hypothalamus (VMH) causes a reduction in the hormonal response to hypoglycemia, and inducing local hypoglycemia in this brain region stimulates a classic counterregulatory hormonal response, the VMH has been recognized as a brain area that plays a key role in detecting and counteracting hypoglycemia. It is currently believed that there is a neuronal network connecting the central nervous system with the alpha cells of the pancreatic islets and the adrenal medulla.
Two main types of neurons sensitive to glycemia fluctuations have been identified. These are GE (glucose-exited) neurons, which respond to an increase in blood glucose concentration, and GI (glucose-inhibited) neurons, whose activity decreases with an increase in glycemia. There is probably a resemblance between GE neurons and beta cells of the pancreatic islets and between GI neurons and alpha cells. GE neurons are active during euglycemia and hyperglycemia, causing inhibition of hormonal counter-regulation, while hypoglycemia stimulates GI neurons, which in turn triggers counterregulatory mechanisms from the endocrine system. In the case of recurrent hypoglycemia, GI neurons become less active because the threshold glucose concentration at which their stimulation begins decreases, while GE neurons become more activated. Additionally, this theory describes the pathogenesis of inadequate counterregulatory mechanisms, which occurs in the case of recurrent hypoglycemia.
In healthy individuals, a decrease in glycemia leads to numerous reactions aimed at restoring the proper glucose concentration in the blood. The basic mechanism protecting against hypoglycemia is the inhibition of the release of endogenous insulin and the production of hormones that act opposite to insulin, e.g., glucagon, adrenaline, growth hormone, and cortisol, which cause the breakdown of glycogen (glycogenolysis), stimulate endogenous glucose production (gluconeogenesis) and limit its peripheral consumption, thanks to which the glucose supply to the brain is maintained at a safe level.
Patients with type 1 diabetes receive exogenous insulin, the release of which is not subject to feedback regulation. In addition, the release of glucagon, which is the main counterregulatory hormone in response to insulin-induced hypoglycemia, is impaired at the beginning of the disease, and after 5 years, it affects most patients with type 1 diabetes. This is associated with the loss of pancreatic islets and adrenergic nerve endings within the islets resulting from the autoimmune process. After 10 years of the disease, most patients experience further disturbances of the counterregulatory mechanisms in the form of a weakened adrenergic response. As a result of the disorders that deepen with the duration of the disease, the risk of severe hypoglycemia increases significantly.
There are three types of hypoglycemia:
We can also distinguish types of hypoglycemia based on the clinical picture and severity of symptoms:
One of the most common types of hypoglycemia is reactive hypoglycemia, also known as functional or postprandial hypoglycemia. As the latter name implies, it is indicated by a decrease in blood glucose levels after consuming, usually within several hours after a meal.
It is one of the kinds of this condition in individuals without diabetes. Interestingly, its etiology is still not completely understood. However, it is presumed that it can be connected with an unhealthy lifestyle, absence of physical activity, an improperly balanced diet, and regular consumption of products with a high content of simple sugars – easily and quickly absorbed by the body.
Sometimes, it happens in individuals with prediabetes or after gastrointestinal surgery. Most often, however, its idiopathic variety can be observed, i.e., the one with an unknown cause.
Manifestation of non-diabetic hypoglycemia is observable when glucose levels drop, and the most significant of them are:
Since the signs of hypoglycemia are usually quite evident, if you notice them, you may react in time and increase the sugar level, e.g., with products including glucose. It is more harmful if this condition happens at night. Then its manifestation can be slept through, which sometimes leads to dangerous situations, e.g., coma.
For this cause, any level fluctuations cannot be overlooked, and if they are diagnosed, it is more promising to remain under regular medical care. Nocturnal hypoglycemia affects diabetics. However, reactive hypoglycemia, discussed above, is characteristic of patients without diabetes.
Due to the time of happening, in addition to decreases in glucose levels at night, it is also occasionally referred to as morning hypoglycemia, i.e., too low sugar concentration occurring right after waking up.
It is the outcome of insufficient glucose synthesis in the liver, which accompanies serious diseases,e.g.:
The manifestations of starvation hypoglycemia are similar to those characteristic of other kinds of hypoglycemia. Nonetheless, because this kind accompanies severe chronic conditions, its signs can coexist with the symptoms of a given situation.
In addition to hypoglycemia induced by internal elements such as conditions or insufficient insulin production, there is also a type known as iatrogenic hypoglycemia, which is caused by external aspects.
The phrase “iatrogenic” refers to harm caused to a patient as an outcome of wrong treatment. In the case of too-low sugar levels, however, drug-induced condition is just one of the possibilities.
Most often, the drop is caused by insulin or other agents that reduce the glucose concentration in the blood. Insulin overdose is usually unintentional, but there are situations of mental illnesses in which individuals intentionally induce hypoglycemia.
Other kinds of iatrogenic hypoglycemia are hypoglycemia after alcohol, a workout, or as a consequence of prolonged starvation. Failure to provide the organism with the right amount of carbohydrates or burn them too intensively during training can significantly reduce blood sugar levels.
The clinical symptoms of hypoglycemia can be divided into neurovegetative (adrenergic, neurogenic) and neuroglycopenic (neurological, psychological). The first ones appear in the early phase of a drop in sugar and are associated with the action of hormones antagonistic to insulin. These may include:
Additionally, knowledge of early symptoms should be an essential element of education for every patient with diabetes.
If the patient misses the above symptoms and does not eat something sweet, neuroglycopenic symptoms result from the brain “starving,” e.g., they may be:
Glucose concentration in the body is regulated by hormones with opposing effects: insulin and glucagon. After a meal, when glucose levels increase, pancreatic cells release insulin. Insulin promotes glucose uptake by muscles and adipose tissue and suppresses glucagon secretion and glucose production by the liver.
Conversely, when blood glucose levels are low, such as during prolonged periods without food, the body activates various mechanisms to prevent hypoglycemia. It primarily affects the inhibition of insulin secretion and a boost in glucagon and epinephrine secretion.
These control mechanisms are disrupted in individuals with diabetes. In type 1 diabetes, the organism either does not produce insulin or does it in tiny amounts. This issue can also occur in the later stages of type 2 diabetes. As a result, hypoglycemia is most commonly seen in diabetics who are treated with insulin and less frequently occurs in those being treated with oral antidiabetic medications, like sulfonylurea derivatives.
The risk of hypoglycemia increases in the following circumstances:
In some cases, however, low sugar may indicate a disease. Hypoglycemia may be associated with:
Check your blood sugar with a blood glucose meter (glucometer) to know if you have hypoglycemia. Most of these instruments use a small blood sample from a finger stab with a tiny needle (lancet).
A CGM could be a valuable instrument in determining and controlling low blood sugar because you may program it to warn you of it. CGM signs may be helpful during periods when it could be risky to have low blood sugar, e.g., while sleeping or driving.
It is significant to manage fluctuations in blood sugar levels, as they may lead to severe health issues.
There are medications available to help lower glucose levels in hyperglycemia. In contrast, the treatment for hypoglycemia (low blood sugar) differs. Mild episodes of hypoglycemia can be treated by consuming foods high in simple sugars, which quickly increase glucose levels. Additionally, after the initial treatment, eat a meal that contains complex carbohydrates, as these are converted into glucose more slowly and provide a longer-lasting effect.
Specific medications, such as glucagon, are administered for severe hypoglycemic episodes that pose a risk to life. In such cases, it is crucial to call for medical help instantly. Medical professionals will typically give an intramuscular injection of glucagon and transport the patient to a hospital.
Once hospitalized, glucose is often delivered intravenously. The primary focus in the treatment of hypoglycemia is to identify and address its underlying causes while alleviating the symptoms.
In the case of overweight or obesity, body weight should be gradually reduced. Obesity is the risk factor for developing type 2 diabetes. With a BMI of 30, the risk of diabetes is six times higher in women and more than four times higher in men compared to individuals with average body weight. Changing the lifestyle of people with obesity and impaired glucose tolerance, consisting of reducing the energy value of the diet, increasing physical activity, and additionally reducing body weight, affects the decrease in the incidence of diabetes.
Eat meals regularly every 3 hours; the first meal is eaten within 1 hour of getting up, and the last is no later than 2-3 hours before bed.
Furthermore, vegetables are a source of dietary fiber, vitamins, and elements with antioxidant properties. Their total daily intake should be around 400-500 g. Various vegetables should be eaten with every meal, raw or cooked al dente or steamed.
Choose unripe fruit that is less sweet, and eat them raw whenever possible. Berries, e.g., blueberries, raspberries, and strawberries are particularly recommended. Combine fruit with products that provide proteins and/or fats to the body. They delay stomach emptying, which extends digestion time and prevents a rapid increase in glucose and insulin concentration in the blood after a meal. Additionally, drinking a glass of 200 ml of fruit juice squeezed from fresh fruit in exchange for eating a portion of fresh fruit on a given day is permissible.
Products that are a source of complex carbohydrates – wholemeal bread, groats, rice, pasta, cereals – should be part of every meal and take up about 1/4 of the plate. Choose wholemeal cereal products because they contain dietary fiber, B vitamins, and many minerals. Furthermore, wholemeal cereal products are digested slowly, which prevents a rapid increase in glucose and insulin concentration in the blood.
Eat products that are a source of protein – meat, fish, eggs, dairy products, and legumes. Choose lean meats and low-fat dairy products. Fish should be eaten at least twice a week. Red meat should be introduced into the diet occasionally, preferably once every 2 weeks. Eliminate meat products from the diet, e.g., fatty cold cuts, sausages, pates, and offal products.
Products that are a source of vegetable fat are part of a full-value meal. They should be introduced in small quantities, e.g., rapeseed oil, olive oil, nuts, chia seeds, psyllium, linseed, pumpkin and sunflower seeds, and avocado, i.e., products rich in unsaturated fatty acids with anti-inflammatory effects. Products that are a source of saturated fatty acids should be limited.
In a diabetic diet, the consumption of sugars should be severely limited, and in some cases, they should be eliminated. The golden mean is to read labels and choose products with reduced sugar content or completely free of it. Sometimes, such products as sugar can be replaced with sweeteners. Natural sweeteners, such as stevia or xylitol, can positively affect health through antioxidant activity. However, the results of studies on the consumption of artificial sweeteners such as sucralose or acesulfame K indicate their potentially adverse effect on the microbiota composition, which is why they are not recommended.
Water is an essential element of a diabetic diet – it helps remove toxins from the body, oxygenates the body, and helps distribute food throughout the body. It takes part in practically every vital function of our body.
Physical activity has a good effect on the health and well-being of people with diabetes. The specialists recommend thirty minutes of physical activity daily. It helps achieve and maintain a healthy body weight, increases tissue sensitivity to insulin, and is a significant element in the prevention of the development of many diseases. Adapt that activity to the individual capabilities and needs of the patient.
Eliminate alcohol from the diet. Drinking alcohol with a meal increases postprandial blood glucose levels and increases insulin levels.
Stop smoking. Quitting smoking reduces the risk of heart attack and stroke, among other things.
Ensure the right quality and quantity of sleep. Try to go to bed and get up at regular periods. Do not use electronic devices an hour before going to bed make it easier to fall asleep.
Additionally, avoid stress – relaxation techniques or meditation are helpful here, they help control stress.
If possible, the glucose level should be measured using a glucometer.
A person who has hypoglycemia but is conscious should consume simple carbohydrates (sugars) containing 15 g of glucose. It can be:
Table of Contents
