Writers 
Chronic stress can manifest as both psychological and physical symptoms.
When a person (or animal) is put in a stressful situation, the body's endocrine system increases the production of a natural steroid called cortisol. The immediate effects of stress hormones can be beneficial by decreasing inflammation in the body, increasing wakefulness and increasing available blood sugar to be utilised by the brain and organs. Sounds ok right?
The trouble is, if you continue to be stressed because of something other than a temporary threat or dangerous situation, let’s say, modern life for example, then cortisol will continue to be elevated. Chronic exposure to high levels of corticosteroids has widespread negative effects on the body. It causes inhibition of your immune system, increasing chances of infection, retention of water and salt leading to high blood pressure and probably headaches, and increased blood sugars can lead to diabetes. There are also detrimental effects on the skin, hair growth and bone density. Also, a multitude of structural effects on the brain can also occur and are associated impaired working memory and spacial memory. Panic attacks, depression and anxiety are all possible.
In short, we evolved the cortisol response to help us during short term threatening and stressful events. This makes it maladapted and very unhelpful in today's high stress world. Life balance and rest are the best treatments.
How can one prevent stress from crossing over into chronic stress?
Stress is normal and can in fact be beneficial. Athletes stress their bodies and train and train and hurt and hurt and some become Olympians.
However we have our various reactions to stress.
Fight or Flight responses with our various hormones, epinephrine, cortisols, and many others have side effects as well.
Physical vs Emotional stress can become no longer protective and become destructive.
How does anyone know they have reached the border zone?
Olympians deliberately cross their own border zones because they have very intense goals.
Regular folk do this as well.
Moms can put up with kid chaos for quite longer than most dads. This is training and goals and determination.
But when mom is getting depressed, anxious, incapable of doing her previous duties, things become noticeable to the family and eventually to the church folk and the moms and others . (I know this is 1950s old school, just examples).
This is same concept with dads or railway workers and train locomotive drivers.
How to prevent crossing over to the destructive level of stress?
Endless books and opinions and various Faith and Psychological measures and rest and exercise and positivity and yoga and chanting and music and travel and writing poems and hobbies. We all are different, one person's stress can be nothing to another person.
Soldiers train and learn what to do in order to deal with which situation.
Fire Fighter train and practice till this type of fire is routine and that type of fire is more challenging and this is what we do for that type of disaster.
Attitude, training the mind, experience, knowing ones station and what is not ones station but being willing to change and learn a new task.
How to not crash? The slow steady turtle will ultimately defeat the fast bunny, an ancient tale.
Goals, available resources, weapons or tools, back up reserves, food, water, sleep, training, attitude of can do change will over time carve out that canyon and get to the moon.
We must be self aware of how we are doing with our path . We must have sensors to tell us how we are doing. ( Self coaches )
We must accept criticism and learn from our errors and learn to evaluate errors and other opinions.
Change, we must be aware of change as a good thing in order to advance or at least not be destroyed.
Is travel stressful ? Yes it can be, So we should rest at certain spots.
So we must set our sights and plans with a goal with graduated stress planned.
Lists of things we must do now, soon, eventually. Maybe never.
Cross off the list of things accomplished and periodically go back and review our lists.
The lists will keep coming and many of the lists will not be accomplished totally.
But the process is a learning process, We will celebrate victories on the way as well .