Smoking, or even living with a smoker, can also cause structural damage to the lungs, and could make someone more vulnerable to certain infectious diseases, he said.
People with unhealthy habits may also be hurting their ability to recover from illness, Dr. Tosh said. Obesity is a predictor of complications from the flu, for instance.
Frequent hand washing is also crucial for keeping bugs from entering the mouth, nose and eyes, where they can spread infections, Dr. Swartz said.
She also recommends annual flu shots to attempt to prevent flu or reduce its severity. Other vaccinations, like the new shingles vaccine, which is now recommended for people 50 and older, are also a good idea to help the immune system.
The immune system’s responsiveness typically declines with age, making older people more vulnerable to many pathogens than they were in their younger days.
The bottom line, Dr. Tosh said, is that a baseline of good health helps keep the immune system strong. “If someone is eating well, exercising, getting a good amount of sleep and avoiding unnecessary stresses, they are less likely to get ill, and if they do get ill, have better outcomes,” he said.
Do you have a health question? Ask Well