How should you use a heart rate monitor?
Measure your heart rate before, during, and after workouts
        
                    
             
        
        
        
Either mechanical or physical. I would say physical though. 
        
                    
             
        
        
        
False, it is actually possible for infants to contract the virus from their mothers during childbirth. 
The most common case of viruses getting passed on to a mother's child during birth is HIV. They can also contract Hepatitis B (not A), herpes, measles, and many other cases.