It is called syncope. Happens to those not used to warm weather and they are trying to stand stock still. Happens to new military recruits, police at events, bosses overseeing work.
Common faint (NMS): this is also known as vasovagal syncope. It is the most common cause of fainting. NMS can occur in various situations. These include:
Fear.
Severe pain or emotional distress.
After extreme exercise.
After prolonged standing, especially in hot places (which is why soldiers on parade may faint).
When wearing tight collars that constrict the neck
http://patient.info/health/faintcollapse
Just watched a video by a (brave) doctor analyzing public information about Hillary’s health issue (video clips, etc.) He said that her coughing is compatible with a swallowing difficulty common to late stage Parkinson’s. Chronic difficulty swallowing from Parkinsons directs saliva incorrectly and over time, can result in pneumonia.