When you have COVID, certain habits can slow your recovery, worsen your symptoms, or fuel the inflammation your body is already fighting. The biggest things to avoid fall into a few categories: substances that suppress your immune system, foods that drive inflammation, physical activity that pushes your body too hard, and lifestyle patterns that rob you of the rest you need to heal.
Alcohol
Alcohol weakens the immune system at exactly the moment you need it working at full capacity. The World Health Organization states plainly that alcohol undermines your body’s ability to cope with infectious diseases and recommends avoiding it altogether during a COVID infection. Heavy drinking in particular raises the risk of acute respiratory distress syndrome, one of COVID’s most dangerous complications.
Beyond the immune effects, alcohol is a diuretic that accelerates fluid loss. Fever, sweating, and reduced appetite already put you at risk for dehydration when you’re sick, and dehydration during COVID is not trivial. In long-term care settings, dehydrated COVID patients had more than double the risk of death compared to those who stayed adequately hydrated. You don’t need to panic about fluid intake, but adding a dehydrating substance to the mix works against you.
Smoking and Vaping
Any form of inhaled nicotine or cannabis makes COVID respiratory symptoms worse. In a study of more than 10,000 outpatients, people who vaped nicotine or cannabis had roughly twice the odds of reporting breathing difficulty compared to non-users, even after accounting for pre-existing health conditions. Smoking cigarettes, using e-cigarettes, and vaping cannabis all showed similar patterns of increased symptoms.
This isn’t limited to heavy smokers. Even occasional vaping was associated with more frequent constitutional symptoms (fatigue, body aches), throat and nasal symptoms, respiratory problems, and gastrointestinal issues. If you currently smoke or vape, a COVID infection is a strong reason to pause. Your lungs are already under stress from the virus, and adding irritants on top slows healing.
High-Sugar Foods and Drinks
Sugar, particularly fructose, actively fuels the inflammatory pathways that COVID is already pushing into overdrive. When you consume sugary foods and sweetened beverages, your body releases the same pro-inflammatory molecules that drive the dangerous “cytokine storm” response in severe COVID cases. In people who are already fighting the virus, this creates a compounding effect where dietary inflammation stacks on top of viral inflammation.
The encouraging news is that cutting back works fast. Research published in the Journal of the Endocrine Society found that reducing fructose intake improved blood pressure, blood sugar control, insulin sensitivity, and inflammatory markers within as few as nine days. During a COVID infection, that means swapping candy, pastries, sugary cereals, and soft drinks for whole foods can meaningfully reduce the inflammatory load your body is dealing with. Stress from being sick also tends to push people toward comfort foods like sweets and baked goods, so it helps to be aware of that pattern.
Intense Exercise
Pushing through a tough workout while you have COVID is one of the riskiest things you can do. The primary concern is myocarditis, or inflammation of the heart muscle, which COVID can trigger even in otherwise healthy people. If myocarditis develops, clinical guidelines recommend no exercise for at least three months, and in most cases six months or longer. Athletes with ongoing heart complications may never fully return to their previous training level.
Even without myocarditis, exercising hard while your body is fighting a viral infection diverts energy away from your immune response. The general guidance from sports medicine specialists is to allow two to three days of gradual return for every training day you missed due to illness. So if you were sick for a week, expect the ramp-up back to normal activity to take two to three weeks. Start with light movement like short walks, and increase intensity slowly. If you notice chest pain, unusual breathlessness, or heart palpitations at any point, stop and get evaluated before continuing.
Skimping on Sleep
Sleep is when your immune system does its most concentrated repair work, and cutting it short has measurable consequences for how quickly you clear the virus. A cohort study of 688 COVID patients found that those with insomnia were significantly less likely to recover from their infection within seven days compared to those sleeping well. Depression symptoms also slowed recovery, while younger age was associated with faster viral clearance.
This means treating sleep as medicine while you’re sick. Avoid screens close to bedtime, keep your room cool and dark, and don’t feel guilty about sleeping more than usual. If congestion is disrupting your sleep, propping yourself up with an extra pillow or using saline nasal spray can help you breathe more easily through the night.
Chronic Stress Without Relief
Being sick is inherently stressful, but letting that stress spiral unchecked has real immunological costs. When your body stays in a prolonged stress state, it releases hormones that suppress the very immune cells (T cells and B cells) responsible for fighting viral infections. Research in psychoneuroimmunology has consistently shown that people under chronic stress are more likely to develop worse upper respiratory infections and take longer to recover.
In the context of COVID specifically, stress activates the inflammatory response, which can compound the virus’s own inflammatory effects. Some researchers have described long COVID as a potential “double hit” of psychological and viral inflammatory stimuli layered on top of each other. While you can’t eliminate stress entirely, simple practices like slow breathing, limiting news consumption, and staying connected with friends or family by phone can help keep your stress hormones from working against your recovery.
Ignoring Hydration
Fever increases your body’s fluid needs significantly, and many people with COVID also experience reduced appetite, diarrhea, or vomiting, all of which accelerate fluid loss. You don’t need to force enormous quantities of water, but steady sipping throughout the day matters. Broth, herbal tea, and electrolyte drinks all count. The goal is to keep your urine a pale yellow color. If it’s dark or you’re urinating very infrequently, you need more fluids.
What About Dairy?
Many people avoid milk and cheese when sick, believing dairy increases mucus production. The evidence doesn’t support a blanket avoidance. A large study actually found that moderate dairy intake, particularly low-fat milk and low-fat dairy products, was associated with lower odds of COVID infection. Low-fat milk cut the odds by roughly half. However, higher intakes of full-fat dairy, cheese, and butter were linked to increased odds. So if you tolerate dairy, low-fat options appear to be fine and possibly beneficial, while heavy consumption of rich, high-fat dairy products is worth limiting.
Returning to Normal Activities
Current CDC guidance recommends staying home until your symptoms have been improving for at least 24 hours and any fever has been gone for 24 hours without fever-reducing medication. Once you resume normal activities, the CDC encourages five additional days of precautions: wearing a well-fitting mask around others, improving ventilation, practicing good hand hygiene, and keeping some distance from people when possible. This layered approach reflects the fact that you can still be contagious even after you start feeling better.