Obesity and Sweating
Obese individuals tend to sweat more due to the increased amount of body fat acting as insulation, which raises the body's core temperature. As a result, the body produces sweat to cool down. Additionally, carrying extra weight can lead to exertion and increased metabolic activity, both of which can trigger increased sweating.
What Is Obesity?
Obesity is a medical condition that is characterized by an excessive or abnormal accumulation of body fat or adipose tissue [1, 2]. Such accumulation of fat and adipose tissue impairs the individual's health [1, 2]. Obesity is typically defined as chronic [1, 2]. In fact, the World Health Organization (WHO) specifies that obesity acts as a risk factor for health [3].
Excessive weight can be caused by the weight of muscle, bone, body water and also fat [4]. However, obesity is measured using the body mass index [BMI], which is a calculation taking into account not only your weight but also your height [5, 6, 7]. Obesity is defined if a person has BMI of 30 or more [5, 6, 7].
Obesity is a complex and multifactorial disease. Herein, it can be influenced by genetic, behavioural and environmental influences. Factors affecting this are habits like overeating, eating high-fat foods or not being physically active as well as your DNA [1, 2, 8, 9].
Obesity also comes with various health risks. It has been associated with an increased risk of diabetes, heart disease, strokes, arthritis and also some types of cancer [10, 2, 4, 7].
The amount of people with obesity is progressively increasing, and it is a significant public health epidemic [1, 2]. It is the second most common cause of preventable death, right after smoking [1, 2].
What Is The Biological Process Of Sweating?
Sweating is natural. We all sweat. In fact, it is the natural mechanism by which the body cools itself down. For us humans, it provides a great potential for heat loss, especially when air temperature exceeds our skin temperature [11, 12].
Physiologically, sweating starts with the stimulation of the anterior hypothalamus in the brain. This happens because of the excess of heat. In turn, it increases the skin's sympathetic nerve activity, resulting in the release of acetylcholine at the neuroglandular junction. The neurotransmitter acetylcholine binds to muscarinic receptors and stimulates the secretion of a primary fluid by the secretory coil of eccrine glands (the fluid is also known as precursor secretion) [11, 13]. The primary fluid travels through a duct where ions are reabsorbed, which results in the expulsion of hypotonic sweat onto the skin surface [14, 15]. The sweat is formed from the contents of disrupted cells as well as from the products of secretion, with fluid transport and exocytosis of vesicles being the principal secretory processes [14, 15].
We humans have two types of sweat glands, eccrine and apocrine. While the eccrine sweat glands are all over our body and their main function is to regulate body temperature, producing light & odourless sweat, the apocrine sweat glands are found in areas with hair follicles (eg. the armpits). The apocrine glands produce more concentrated secretions of sweat, which is associated with body odour [12].
Sweating increases in proportion to the intensity of the thermal challenge in an attempt of the body to attain heat balance and maintain a stable internal body temperature. The control of sweating can be modified by biophysical factors, heat acclimation, dehydration, and nonthermal factors [11].
Why Do Obese People Sweat?
The body of an obese individual needs to use more energy to function. This is because the body has a higher weight and hence it uses more energy to operate. Such usage of energy may result in more sweat because there is more body mass to cool down [16].
Another possible reason is that people with obesity have a larger surface area. So the more skin you have, the more places there are to sweat from, which may appear as excessive sweating [17]. With this, obese individuals have more skin folds, due to large pockets of body fat. These skin folds may capture moisture and contribute to increased sweating [17].
In addition, obesity can affect our body’s ability to regulate temperature properly, known as thermoregulation. Some studies showed that patients with obesity are less efficient at thermoregulation than healthy controls, which may lead to increased sweating [18].
Lastly, certain studies have shown that obese individuals may have higher temperatures in heat-dissipating regions of the body, such as the hands, which could potentially lead to increased sweating [19].