Excessive sweating medically referred to as hyperhidrosis, is a condition in which you find yourself sweating more than usual even without exercising, being in a hot environment, or due to overwhelming anxiety.¹ You may find your whole body, or some parts of it, overly sweating due to your sweat glands not switching off even when you are sitting down or under air conditioning. In the majority of the cases, this disorder may transpire for no apparent reason or as a side effect from an existing condition or medication. 

Excessive sweating can be accompanied by stomach pain. Stomach pain, also known as abdomen pain, is characterised as discomfort, cramping, dull, or aching pain that occurs between your chest and the pelvic area.² 

Depending on the severity of the pain and sweat, these two symptoms arising together warrant a visit to your doctor to rule out any possible medical condition, especially if you are in extreme pain and discomfort. It is important to check for any underlying causes to ensure that prompt treatment can be assured. 

Gastrointestinal-related causes

Gastrointestinal (GI) (GAS-troh-in-TES-tih-nul SIS-tem) system consists of organs that absorb food and liquids and convert them into compounds the body can use for growth, repair, and energy. Thus, diseases of the GI affect the stomach, intestines, and the oesophagus. These can range from mild to serious, depending on the severity of the symptoms.³

Irritable bowel syndrome (IBS)

Irritable bowel syndrome (IBS) (EER-ih-tuh-bul BOW-ul SIN-drome) is a chronic bowel disease that affects the digestive system. It is marked by a set of symptoms that typically include cramping discomfort, bloating, constipation, stomach pain, and diarrhoea.⁴ 

This syndrome is caused due to several factors; one of these include the dysregulation of the gut-brain axis (GBA). The GBA is a bidirectional communication between the central nervous system, which holds the brain, and the enteric nervous system, which is a network of nerve cells in the digestive tract that regulates digestion.⁵  It connects the brain's emotional and cognitive centres to peripheral gut processes via direct and indirect channels, namely the vagus nerve. Similar to a wire that connects the brain to the heart, gastrointestinal tract, and lungs, the vagus nerve serves as a link between these organs. The vagus nerve is generally sensed and activated by gut microorganisms and metabolites that respond to nutrition, such as short-chain fatty acids (SCFAs), as well as by endocrine factors, enzymes, and neurotransmitters, such as serotonin and dopamine, among others. 

This communication can get disrupted in IBS. Its pathophysiology includes producing low-grade inflammation, reducing intestinal mucosal integrity, and altering the composition of gut microbes. When this occurs, IBS symptoms, in particular, stomach pain, can be persistent and prevalent. 

In addition, the dysregulation of the GBA leads to the activation of the sympathetic nervous system, which is often responsible for the “fight-or-flight” response. This activation may lead to excessive perspiration, especially during flare-ups that are accompanied by abdominal pain or discomfort. Stress hormones such as cortisol and adrenaline exacerbate this reaction, which causes excessive sweating. When you have physical symptoms such as bloating or diarrhoea, this physical stress can also lead to further sweating as your body attempts to maintain equilibrium and control body temperatures.⁶

Food poisoning

Food poisoning is an illness caused by consuming spoiled, contaminated, or harmful food or liquid, resulting in sickness. Although this condition is rarely serious and most people recover quickly, an individual may abruptly find themselves feeling:⁷

• Nausea
• Diarrhoea
• Vomiting
• Sweating profusely 
• A fever of 38°C or higher
• Stomach pain 
• Fatigue
• Muscle aches 

When a food is contaminated, this means that the item is infected with pathogens, such as bacteria, viruses, and parasites, or the food may have come in contact with microbes from vomit or faeces - this may be from a sick individual who has prepared the food without washing their hands. These pathogens can therefore trigger the autonomic nervous system, which regulates certain body processes, such as blood pressure and the rate of breathing, and results in a painful response. 

The symptoms exhibited from food poisoning can also cause an electrolyte loss, in particular from vomiting and suffering from diarrhoea, leading to a physical strain on the body from having to balance the regulatory systems. In addition, sweating can transpire in a fever, as the body tries to control its temperature and burns more fluid, leading to dehydration.⁸

Gastroenteritis

Gastroenteritis, or also the stomach flu, occurs when the stomach and intestines become irritated and inflamed. This may result in gradual syndromes, including diarrhoea, vomiting, cramps, nausea, and stomach pain. It is typically caused by inflammation brought on by your immune system's reaction to a bacterial or viral infection. However, gastroenteritis can also result from a chemical irritation or infections brought on by fungus or parasites.⁹

Excessive perspiration is a reaction to infection that is frequently associated with fever, dehydration, and the activation of the autonomic nervous system. This reaction may be further emphasised with the physical strain that the body goes through due to nausea and vomiting.  As a result, your body may try to maintain its temperature and cope with the stress that the virus has caused internally.⁹

Acid reflux (GERD) 

Acid reflux is a burning sensation in which stomach acid runs back up into the tube linking the mouth and stomach, known as the oesophagus. It may also be known as gastro-oesophageal reflux disease (GORD). When the stomach acid travels back to the oesophagus, the lining of the latter can be irritated and cause discomfort and pain. Acidic stomach contents irritate the vagus nerve endings in the oesophagus, causing reflex bronchoconstriction in the lungs, which is likewise mediated by the vagus nerve. 

The vagus nerve may be triggered by severe episodes, resulting in symptoms like nausea, dizziness, and sweating. This reaction, when combined with the physical discomfort of acid reflux, can trigger an activation of the sympathetic nervous system, which exacerbates discomfort and profuse perspiration.¹⁰

Other possible causes

Although diseases related to the GI tract are more prominent in causing pain in the abdomen and excessive sweating, other factors could also cause these symptoms to arise. These include:^11,12

• Medication side effects—some drugs can result in a reaction with the digestive system or the autonomic nervous system 
• Heatstroke or overexertion—Overly tiring your body can lead to abdominal cramps and dehydration, especially if you do not allow your body to rest 
• Hypoglycemia—When your blood sugar falls too low, you have hypoglycemia, commonly referred to as low blood sugar. This can affect the signalling of the vagus nerve, which cause sweating and discomfort of the stomach¹¹
• Panic or anxiety disorders—Stress or anxiety can trigger your fight-or-flight response by releasing stress hormones, which in turn can manifest into physical symptoms 
• Adrenal disorders—When the adrenal glands generate too much or too little of a certain hormone, it can lead to adrenal diseases, such as Addison's disease or Conn's syndrome. The type of disease and the degree to which hormone levels are affected determine the symptoms¹²

When to seek medical attention

Contact your general practitioner if:^1,2

• Your excessive sweating has been ongoing for at least 6 months, and has interfered with your daily activity
• You have a family history of excessive sweating
• Bloating or stomach ache that doesn't go away or keeps returning
• You are taking medication for a different condition 

If your doctor believes that another condition is the cause of your sweating and stomach ache, they may recommend that you get tested.

You should immediately call 999 or go to the emergency services if you experience any of the following: ^1,2

• Blood in the stool
• Cannot breathe and/or chest pain
• A fever of 38°C or more that is not going away
• You feel pain when you touch your stomach
• Severe stomach pain that has come on suddenly, and escalated to the stage where you cannot sleep, cannot move, find it difficult to talk and think
• Cannot pass gas or there is no bowel movement
• Cannot urinate
• If you are diabetic and vomit

Summary

Excessive sweating is defined as sweating beyond required for the body’s regulation. Stomach pain, however, is characterised as a cramping ache that occurs between your chest and the pelvic area. Numerous illnesses might cause excessive perspiration and stomach aches. Gastrointestinal causes include food poisoning, which induces a stress reaction because of toxins, or gastroenteritis, where infections cause inflammation in the abdomen and systemic symptoms like fever and perspiration. The vagus nerve may be triggered by GERD, irritating the oesophagus and resulting in pain and perspiration. Hormonal imbalances or increased nervous system activity can also cause similar sensations in systemic illnesses, including hypoglycemia, adrenal problems, or anxiety. For effective treatment and symptom management, these underlying causes must be found and addressed. Immediately go to the doctor if you feel seriously unwell.