Increased metabolism through saunas?
When taking a sauna in a infrared sauna, the body tries to cool itself in several ways as a reaction to the deep warming. This generates increased heart activity in both frequency and volume.
The metabolic process (metabolism) increases and the blood vessels dilate to bring the heated blood from inside the body to the skin more easily.
The heat is transferred to sweat that evaporates through the skin. This process of cooling the body creates similar cardiovascular benefits as work-outs. The use of long-wave infrared sauna has been described as a form of passive exercise. In a Luxway infrared sauna, two to three times as much sweat is generated as in a traditional sauna bath.
To produce 1 gram of sweat requires 0.568 kcal. A Luxway infrared sauna of 30 minutes corresponds on average to a burn of about 600 kcal.
This varies according to the body's condition in heat, i.e. how much sweat the body can produce in a sauna.
You simply sweat off 500 grams which corresponds to 300 kcal but for a person with higher sweat production can reach a burn of 800 kcal.
For comparison; a 70kg person normally burns after 30 minutes of the following activities
Fat, what is it ?
Fat is a special type of tissue that contains many fat cells, on average we have around 50 billion fat cells. Fat tissue is mainly found between the skin and the muscles where it forms a fat reserve called subcutaneous fat. Fat can also be stored around organs, a clear example of which is the infamous beer belly. Fat stores protect the muscles and organs from impact. A man normally has 10 - 20 per cent fat and a woman 20 - 30 per cent.
There are two types of fat cells, brown and white, and they differ in both appearance and function. Brown fat cells are made up of several small fat droplets and contain many mitochondria, the 'powerhouse' of the cell. The main function of mitochondria is to produce energy. It is the presence of blood and mitochondria that makes the fat look brown. Brown fat cells are found mainly in newborns, who cannot yet use their muscles to keep warm. This makes brown fat very important, as it provides almost all the energy in the form of heat when broken down.
White fat is a more common type of adipose tissue and is found in older children and adults. White fat cells are larger than brown fat cells and consist of one large fat droplet instead of several small ones. The breakdown of white fat releases both chemical and thermal energy.
From dietary fat to body fat
Fat is burned in many of your body's cells, but muscles and certain organs, such as the liver, are the main tissues responsible for burning fat. You can't burn fat in one spot, it is taken from all your fat cells at the same time. Fat burning is a slow and difficult process, which can be affected in several ways. When you gain weight, you gain more adipose tissue and it uses less energy than muscle, which slows down your metabolism.
The body can obtain energy by breaking down fat, which is either taken from the diet or from the cell's own fat stores. Fat is present in the diet in the form of triglycerides, saturated and unsaturated fatty acids and cholesterol. Unlike other nutrients that start to be broken down in the mouth and stomach, the actual breakdown of fat does not begin until the small intestine. Here, bile acids and the digestive enzyme lipase break down the fat into smaller components (glycerol and short chain fatty acids). These are absorbed directly by the intestinal cells and transported via the blood to the muscles and elsewhere.
Key hormones control fat burning
The balance between storing and using fat is controlled by the nervous system in combination with various hormones.
Insulin
One of the most important regulatory hormones is insulin, whose main function is to signal the body's cells to take up sugar from the blood after a meal. However, insulin has another important function in the metabolism of fat. It stimulates the production of an enzyme called LPL, lipoprotein lipase. LPL in turn signals fat cells to absorb and store fat. This is why insulin is called the body's most fat-forming hormone.
Leptin
Our ability to regulate how much fat is stored is also controlled by another important hormone, leptin, which is produced in fat cells. Leptin is released when we eat too much or simply when we have too much fat in our bodies. The hormone travels with the blood to the hypothalamus, the part of the brain that controls, among other things, food intake, which then sends signals to suppress appetite and increase metabolism. Some people lack a functioning gene for this hormone and may therefore gain weight easily.
Resistin
A relatively newly discovered hormone, resistin, may be a major contributor to obesity. Resistin is produced by fat cells and inhibits the ability of insulin to stimulate the uptake of sugar into the body's cells. This means that cells suffer from a condition known as insulin resistance, which is common in type 2 diabetes. Insulin resistance is often an important sign of obesity. Further studies are needed to reveal the exact mechanism, but there is definitely a link between the hormone resistin and fat metabolism in the body.
Why do we gain weight so easily?
The answer to this question is evolution. Humans have adapted to a variable supply of food in the form of a built-in reserve of fat. Those who could eat a lot and also store energy when food was available simply survived longer. The reason why women evolved to have more fat cells than men was to cope with pregnancy during a period of starvation.
When the body senses that food is in short supply, it tries to retain fat. When dieting hard, the body thinks it is in a period of starvation, the metabolism slows down and fat storage increases. However, the difference between modern humans and Stone Age humans is the amount of everyday exercise. Our ancestors led physically demanding lives, whereas our lives are dominated by more sedentary activities. In other words, gaining weight is natural but we should move more to feel good.
Pregnancy, breastfeeding and menopause affect
Stone Age women depended on a fat reserve during pregnancy and breastfeeding. This is still evident today, with women putting extra energy into their hips and thighs in particular during pregnancy. Fat stores are needed during the last part of pregnancy and during the breastfeeding period, when the mother is not always able to eat enough for her needs and those of the newborn baby. It is normal to gain 10-12kg during pregnancy and dieting is not recommended.
Some weight gain at menopause is natural as the metabolism slows down, muscle mass and calorie needs decrease, and the ovaries produce less oestrogen. This is when fat cells intervene and start producing oestrogen to keep a woman's hormone levels in balance. Fat cells become more numerous, larger and increase their ability to store fat. Most often, menopausal women complain about fat settling around the waist, because the fat cells at the waist are better at producing oestrogen than the fat on the thighs and buttocks. The average woman gains about five kilos, but an accepted healthy weight gain can be two to ten kilos.
Abdominal fat is known to increase the risk of cardiovascular disease in men. What about women? Research has shown that women's waist fat is less active than men's. Fat cells are so busy making oestrogen that they don't release as much fatty acid to the liver to make cholesterol.
Size of fat cells
Some specialists believe that the number of fat cells develops at an early age and we cannot change their number. However, we can influence the size of fat cells by gaining weight. Others believe that there is a link between obesity and the number of fat cells. Fat cells have a limit to how big they can become and when that limit is reached, the cells divide.
Some dietitians consider this limit to be 15 kilos overweight. When you gain more weight, the existing fat cells start to divide and form new fat cells. This can result in a long-term tendency to put on weight. Less excess weight is due to existing fat cells being filled with fat, which can be worked off relatively easily. Existing excess weight tends to increase with age, as the metabolic rate in adults decreases by about one per cent per year. When dieting, fat is broken down but fat cells do not disappear, so it is easy to gain weight after the dieting period.
Some people may find it difficult to become thin, no matter how much they diet, because they have many small fat cells that cannot be made smaller. Those who become overweight as children tend to have more small fat cells, while those who become overweight later in life have fewer but larger fat cells.
Is there a cure for obesity?
We gain weight when there is an imbalance between energy intake and expenditure. Obesity increases the risk of several dangerous diseases such as cancer, adult-onset diabetes, cardiovascular disease. In men, fertility is impaired because the amount of the hormone testosterone in the blood is reduced, while increased levels of subcutaneous fat lead to an elevated level of oestrogen.
Much of today's research centres on the hormones that control appetite. The hope is to invent a drug that will switch off the body's hunger signals to the brain and make us eat less. But appetite is a complex system that is difficult to regulate. The anti-obesity drugs developed so far fall into three categories. Drugs to make us eat less, drugs to increase metabolism and drugs to make the gut absorb less fat. None of these pills work very well.
Dietitians around the world recognise that one of the main reasons why over half of the world's population is overweight is lack of exercise