You may develop a low-grade fever with an upper respiratory infections (URI); it’s not common, but also not impossible. If, however, that fever reaches 101 degrees or higher, there’s a greater chance that URI has developed into pneumonia. (Related: Could it be a sinus infection? Here are common sinus infection symptoms.)
Rapid heart rate
If during your illness you notice your heart beating faster than normal, take a moment to check your heart rate. Anything over 100 beats per minute is considered a rapid heart rate. If a rapid heart rate persists, seek medical attention. Learn why pneumonia can increase your heart attack risk.