The topic: antibiotics, a class of drugs used to fight things like urinary tract infections, strep throat, and ear infections
“Antibiotics are generally non-discriminatory,” explains Holly Niles, CNS, functional nutritionist in West Palm Beach, Florida. They destroy harmful and healthy bacteria alike, most notably in your gut microbiome.
By throwing off the balance in your gut, antibiotics may leave you with brain fog and low energy, in part because they affect your ability to absorb nutrients from food. That’s why working out can seem more exhausting than normal when you’re taking them.
The gut effect can also decrease your immunity, slowing your recovery from exercise and making you more susceptible to new infections, she explains. Your vulnerability can set in while you’re on the meds and linger for a few weeks.
There are also mental effects. A single round of meds can cause mood issues like anxiety by altering your body’s ability to produce neurotransmitters like serotonin, she explains. This, too, can persist beyond the round of antibiotics until gut balance is restored. The process can take anywhere from two weeks to a few months, depending on initial gut health and the strength of the antibiotic.
Some of the risks depend on the type of medication, notes Stanley Deresinski, MD, clinical professor of medicine specializing in infectious diseases at Stanford University in California. For example, a class of drugs called fluoroquinolones (used to treat sinus and urinary tract infections) can cause tendonitis, potentially by reducing the amount of magnesium in the tendons. This risk may be four times higher with fluoroquinolones than with other antibiotics.
Deresinski notes that 30 to 50 percent of antibiotic prescriptions are unnecessary. “They only work if whatever ails you is caused by bacteria,” he explains. They have no effect on viruses but are often given for mysterious fevers and coughs, which are sometimes bacterial but typically viral.
When used properly, they can treat common bacterial infections like UTIs and strep and even those that were formerly fatal, including sepsis and blood infections. “Sometimes they’re absolutely essential and life-saving,” says Niles.
The final analysis:
Antibiotics aren’t innately bad, but they shouldn’t be your first defense against every bacterial infection. Talk to your doctor about whether there's anything else you can try first, like cutting out sugar and alcohol, skipping intense exercise, hydrating better, or eating a vegetable-rich diet, Niles says. Those changes can reduce inflammation, strengthen immunity, and help your body fight infection without meds.
If you have a serious bacterial infection like pneumonia or a staph, your doctor will likely insist that antibiotics are necessary.
When you’re on the meds, Niles suggests eating nutrient-dense, plant-based foods to promote microbiome balance. Research shows taking probiotics after your antibiotic cycle can negatively impact gut health. Avoid them for at least three weeks post-treatment.
Niles also recommends subbing high-intensity work with gentle movement like walking or yoga. If you don’t feel up for exercise at all, rest until your energy levels bounce back; pushing too hard while your immunity is low will only increase your recovery time.