Muscle spasms and related muscle pain, known as myalgia, are frequently reported symptoms associated with COVID-19 infection. The discomfort ranges from mild aches to more intense cramps or spasms that can interfere with daily activities. This experience is a recognized manifestation of the body’s reaction to the SARS-CoV-2 virus, affecting a significant number of individuals who contract the illness. Understanding the direct link between the viral infection and muscle issues helps validate the symptoms many people experience during and after the acute phase. The presence of these muscle symptoms is one of the many ways COVID-19 can impact the body beyond the respiratory system.
Biological Causes of Post-COVID Spasms
The primary driver behind muscle spasms and pain during a COVID-19 infection is the body’s immune response to the invading virus. When the immune system detects the SARS-CoV-2 virus, it releases signaling proteins called cytokines to coordinate the defense. This systemic inflammation, often referred to as a “cytokine storm” in severe cases, leads to irritation and inflammation of muscle fibers, a condition known as myositis. Inflammatory cytokines like interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) are known to directly cause muscle and joint pain by promoting inflammation within the tissue.
Beyond inflammation, the virus itself may potentially cause direct damage to muscle tissue. Muscle cells express the angiotensin-converting enzyme 2 (ACE2) receptor, which the virus uses to gain entry into cells.
Another significant contributing factor to muscle spasms is the disturbance in the body’s electrolyte balance. Viral illnesses, especially those accompanied by fever, vomiting, or diarrhea, can lead to dehydration and imbalances in minerals like potassium, magnesium, and calcium. These minerals are essential for proper nerve signaling and muscle contraction and relaxation. Low potassium (hypokalemia) and low magnesium levels can increase neuromuscular irritability, making muscles more susceptible to involuntary contractions and painful spasms.
Timing of Spasm Onset
The timing of muscle spasm onset relative to the infection can generally be divided into two phases: acute and post-acute or persistent. Acute-phase spasms and myalgia typically occur during the initial infection, often starting alongside or even before common respiratory symptoms like cough or fever. In this stage, the spasms are largely a direct result of the high levels of systemic inflammation, cytokine release, and potential dehydration from the acute illness.
These acute muscle symptoms usually resolve within two to four weeks as the body clears the virus and the inflammation subsides. However, for some individuals, the muscle symptoms persist or even begin weeks or months after the initial infection has passed, falling under the umbrella of “Long COVID.” These persistent spasms are often linked to ongoing, low-grade inflammation, neurological issues such as small fiber neuropathy, or chronic pain syndromes.
The development of muscle pain in the post-acute phase is defined as symptoms lasting beyond four to twelve weeks. This suggests that the initial interaction between the virus and the host’s immune system may influence the risk of long-term muscle issues. Symptoms in the persistent phase can fluctuate over time and are frequently accompanied by other Long COVID symptoms like fatigue and post-exertional malaise.
Relief and Medical Management Options
Managing post-COVID muscle spasms often begins with self-care strategies focused on reducing muscle irritation and restoring balance. Maintaining adequate hydration is fundamental, as even mild dehydration can worsen electrolyte imbalances and muscle cramping. Gentle stretching and light movement, while respecting the body’s energy limits, can help prevent muscle stiffness and improve blood flow.
For immediate relief, over-the-counter pain relievers like acetaminophen or ibuprofen can help manage the general muscle aches and reduce inflammation. Applying heat, such as through a warm bath or a heating pad, can relax tense muscles and soothe spasms. Cold therapy may be beneficial for localized inflammation. Pacing physical activity and avoiding overexertion are also important, particularly for those whose symptoms worsen after activity.
If spasms are severe, unilateral, or accompanied by significant weakness, consulting a healthcare provider is necessary to rule out other conditions and explore prescription treatments. Medical management may include targeted magnesium supplementation if an imbalance is detected, or a short course of muscle relaxants to interrupt the spasm cycle. A referral to physical therapy is also common, as therapists can develop a structured, low-impact exercise regimen to strengthen muscles and improve function without triggering post-exertional symptom flares.