Overview

Excessive sweating (hyperhidrosis) is a medical disorder due to overstimulation of eccrine glands (sweat glands). It is characterised by excessive sweating beyond the normal, which your body needs to regulate the temperature. According to research, it can occur at any age but is most common in people aged between 20-60 years, and it causes physical, emotional and mental discomfort that impacts patients' quality of life.¹

Excessive sweating is classified into two categories such as primary and secondary hyperhidrosis. Primary hyperhidrosis is mainly based on family history, whereas secondary hyperhidrosis happens due to another medical condition. Multiple treatment options are available including medicines, topical agents and botulinum toxin injections, but our main goal of treatment is to reduce excessive sweating with fewer complications.²

Muscle weakness is a lack of muscle strength when your muscle cannot perform normal tasks, is hard to move causing it to lose its functionality. Muscle weakness is more prevalent in adults 60 years or older, and it is different from normal pain and fatigue. Short-term muscle weakness is common, but if symptoms persist for a longer period, it could indicate an underlying condition.³

After reviewing the basics of hyperhidrosis and muscle weakness, the main focus of this article is to know the potential causes of excessive sweating and muscle weakness. Multiple factors or comorbid conditions, including exercise, dehydration, diabetes, autoimmune diseases, hormonal diseases, infections, medicines, nutritional deficiencies, anxiety and more become the cause of excessive sweating and muscle weakness,^1,3 which will be discussed further:

Potential causes of excessive sweating and muscle weakness

Excessive sweating and muscle weakness can occur due to the following factors and medical conditions. These are:

1. Endocrine disorders

Hyperthyroidism

Hyperthyroidism is when your body produces too much thyroid hormone (triiodothyronine t3 and thyroxine t4) via thyroid glands. These hormones control multiple functions of the body and are responsible for controlling body temperature and muscle breakdown. Any dysregulation with thyroid hormone can cause excessive sweating and speed up muscle breakdown, which gives rise to muscle weakness.^4,5

Adrenal disorders

An adrenal gland is a small, triangular-shaped gland present on top of both kidneys, and it is responsible for producing hormones like cortisol, aldosterone, epinephrine and norepinephrine. Too much or too little adrenal hormones can cause adrenal disorders. Examples are Cushing’s syndrome (high level of cortisol), pheochromocytoma (adrenal tumour), Addison's disease (adrenal insufficiency), and hyperaldosteronism (high aldosterone level). Almost all the disorders show symptoms of muscle weakness and excessive sweating due to dysregulation in hormones.⁶

Menopause

Excessive sweating and muscle weakness can happen after menopause due to changes in hormonal levels (estrogen and progesterone). Rapid reduction in oestrogen levels can make you sweat more than average, and your muscles become weaker and lose their mass and strength.⁷

2. Neurological disorders

Multiple sclerosis

Multiple sclerosis is an autoimmune disorder that affects the brain and spinal cord by damaging the protective covering of nerve cells called myelin. Any damage to the myelin sheath could disrupt the regular functions of the body. Causing excessive sweating by damaging the thermoregulatory system and muscle weakness by impairing muscle movement and function.^8,9

Parkinson's disease

Excessive sweating and muscle weakness or stiffness are common signs shown in Parkinson's disease. It is a brain disorder in which nerve cells, particularly dopamine become impaired or die and it results in problems with movement, balance, skin problems, coordination and more.¹⁰

Autonomic dysfunction

Autonomic nervous systems control involuntary functions of the body, including heart rate, the respiratory system, blood pressure, temperature, muscle movement, and bladder control. Autonomic dysregulation can damage nerves, which impairs their function, and all the functions of the body are compromised.¹¹

3. Metabolic disorder

Diabetes

Diabetes is high blood glucose levels, and it can damage nerves around your body, this is known as diabetes neuropathy. Damaging nerves can disrupt the ability of the body to control temperature and sweat, it can also affect muscle movement and make them weak.¹²

Electrolyte imbalance

Electrolyte imbalance happens when your body has too much or too little electrolyte (sodium, potassium, calcium, chloride, magnesium) in your blood. Each electrolyte has different functions and regulates body fluid, rate, controls nerves, and muscle mobility. Excessive sweating and muscle weakness are symptoms of electrolyte imbalance.¹³

4. Infection

Viral and bacterial infections:

Viral and bacterial infections, including dengue, influenza, covid 19, tuberculosis show symptoms like sweating or muscle weakness due to their immune response. The severity of these symptoms varies for individuals, it is temporary, and it goes with time.¹⁴

5. Medicines

Medicines that induce excessive sweating because they act on the hypothalamus or thermoregulatory system that controls body temperature, and they can make patients uncomfortable or embarrassed. these include:¹⁵

• Cholinesterase inhibitor (donepezil, rivastigmine)
• Selective serotonin reuptake inhibitors (SSRIs) (sertraline HCL)
• Opioids (codeine, morphine, hydrocodone)
• Tricyclic antidepressants (amitriptyline, imipramine)¹⁵

Medicines that cause muscle weakness by causing low potassium levels in the body, decrease muscle fibre and speed up muscle breakdown, and these are:¹⁶

• Colchicine
• Chloroquine
• Zidovudine
• Cyclosporine
• Cimetidine 
• Corticosteroids
• Antibiotics (d-penicillamine)
• Beta Blockers (propranolol, bisoprolol) 
• Chemotherapy medicines¹⁶

6. Psychological factors

Anxiety and stress

Everyone faces stress and anxiety; it's a part of daily life, but do you know it harms our physical health. If you don't overcome stress and anxiety for a longer period it will affect every body part, and excessive sweating and muscle weakness are among them. Excessive sweating is an immune response to stress and anxiety (fight or flight response). On the other hand, when you feel stress, tension is produced in your muscles, which can cause further weakness and stiffness.¹⁷

Panic attacks

Excessive sweating and muscle weakness are common in individuals who suffer from Panic attacks. Panic attacks are characterised by frequent feelings of fear, losing control over things and anxiety, and if these attacks persist for a longer period, they show symptoms physically; these symptoms can happen at any time.¹⁸

7. Nutritional deficiencies

Vitamin deficiency

According to research, vitamin D deficiency can cause muscle weakness. It shows that vitamin D level less than 10 ng/ml results in muscular issues because vitamin deficiency impacts nerves and muscles. Therefore, people with muscle weakness should check their vitamin D levels and take supplements if necessary.¹⁹ Moreover, low vitamin levels and low magnesium levels can induce sweating.²⁰ Vitamin B12 deficiency induced night sweats.²¹

8. Other causes

Dehydration

Dehydration is when your body doesn't have enough water content, or is a side effect of fever, vomiting or diarrhoea, where the body loses its water content. The body is made up of 75% water; therefore, it is important to maintain an adequate amount of water in the body. Dehydration can cause muscle weakness because low water content reduces the blood flow to muscles, impairing their ability to function and move properly.²²

Over-exertion

When you do too much physical or mental activity or effort, it is known as overexertion. Anything beyond the normal can cause a negative impact, be it on your body or brain. It can cause pain and discomfort. Too much physical activity or exercise could lead to excessive sweating and muscle injury or tissue breakdown.²³

Summary

In this article, we explore the potential causes of excessive sweating and muscle weakness. Excessive sweating refers to sweating that goes beyond the normal or average amount, while muscle weakness occurs when movement becomes difficult or the muscles lose their ability to function properly. Various factors can contribute to these symptoms, including hyperthyroidism, adrenal disease, menopause, multiple sclerosis, Parkinson’s disease, diabetes, electrolyte imbalances, viral and bacterial infections, medications, panic attacks, and deficiencies in vitamin D and B12. Dehydration and overexertion can also play a role. A detailed review of these causes is provided. If you have been experiencing persistent symptoms like excessive sweating or muscle weakness, it’s important to consult with a doctor for a proper diagnosis, as even minor signs could indicate a more serious underlying condition.