Cold water immersion (CWI), often called a cold plunge, involves submerging the body into water typically below 59°F (15°C). This practice has grown significantly in popularity, driven by claims of mental resilience, enhanced recovery, and health benefits. The physiological shock of the cold water triggers a cascade of responses. This leads to a common question: is cold plunging advisable when the body is already battling a common cold? The answer depends entirely on the severity of the illness and the body’s current state.
Is It Safe to Plunge While Sick
The primary concern with cold plunging during illness is the intense strain it places on the body’s regulatory systems. If you have a fever, which indicates your body is actively raising its core temperature to fight a pathogen, a cold plunge is strongly discouraged. Introducing extreme cold disrupts this delicate thermoregulation, potentially worsening the fever response and confusing the body’s natural defense mechanism.
The shock of cold water causes rapid vasoconstriction, narrowing blood vessels and shunting blood away from the extremities toward the core to protect vital organs. This sudden narrowing and resulting spike in blood pressure and heart rate stress the cardiovascular system, which is already working harder to support an active infection. Combining the stress of illness with the significant stress of CWI increases the risk of complications such as hypothermia, fainting, or undue cardiac strain. Even a mild cold compromises resilience, making the body less equipped to handle the deliberate physiological challenge of a cold plunge.
Cold Plunge Effects on the Healthy Immune System
For healthy individuals, regular cold exposure is a form of hormetic stress—a low-dose stressor that prompts beneficial adaptation. This controlled challenge trains the body to respond more efficiently to future stressors. A studied response is an acute increase in the circulation of immune cells.
Immediately following a plunge, there is a measurable spike in white blood cells, specifically lymphocytes and monocytes, which are crucial for fighting infection. Consistent CWI may contribute to a reduction in chronic systemic inflammation. The activation of the vagus nerve during cold exposure is theorized to promote a calmer, more balanced nervous system state, which supports immune resilience.
How Cold Exposure Interacts with an Active Cold
When the body is actively fighting a cold, introducing a cold plunge can be counterproductive because CWI triggers a massive, acute stress response. The immersion causes a surge in stress hormones, including norepinephrine and cortisol. While this cortisol spike is temporary, it may temporarily suppress the immune response precisely when the body needs full strength to combat the virus.
The body’s resources are entirely dedicated to the active immune battle, and extreme cold exposure diverts energy and attention away from this primary task. Fighting an infection requires metabolic energy, and forcing the body into a thermoregulation crisis can deplete reserves needed for recovery. The stimulating effect of the plunge may also create a false sense of well-being, masking the true extent of the illness and potentially leading to overexertion. This additional stress can prolong recovery time.
Safe Exposure Alternatives and Resumption Guidelines
Instead of full cold water immersion, individuals with a cold can opt for milder, localized cold exposure methods that reduce systemic stress. A brief cold shower, particularly a lukewarm one, provides a gentler stimulus without the cardiovascular shock of a full plunge. Applying a cold compress or an ice pack can target symptoms without overwhelming the entire system.
Prioritizing rest, hydration, and nutrition is the most effective strategy when recovering from an infection. Before resuming the practice, it is advised to be completely symptom-free for a period of 24 to 48 hours. This wait time ensures the infection is fully resolved and the body’s energy reserves are restored before the stress of CWI is reintroduced. When returning to plunging, it is wise to start with shorter durations and slightly warmer temperatures to allow for gradual re-acclimation.