Stress is inevitable in life. The human stress response is something given to us since birth. Yet, we often feel habituated to resist (stressing out further about being stressed) or escape it (i.e., by consuming tobacco, alcohol).
Stress that lasts weeks to months or longer.
It's okay to have stress levels going up and down throughout the week, but it should never stay high for a long time. 
What are the potential threats to chronic stress?
Evolutionarily, stress is a series of biological mechanisms designed to help us react fast to life-threatening situations. Under stressful situations, our brain (amygdala and hypothalamus) activates the 「sympathetic nervous system」to release stress hormones (adrenaline and cortisol) into the blood and activate the "fight or flight" response. You've probably experienced the stress response by feeling a sudden increase in heart rate, faster breathing, and sweating. 
Chronically, however, stress can have debilitating consequences:
Persistent adrenaline surges can chronically constrict the blood vessels, increasing blood pressure and increasing the risks of heart attacks .
Chronically increased cortisol leads to the buildup of fat, weight gain, and fatigue due to its effect on shifting metabolism to store fat .
What should I do to mitigate stress?
Increase the stress threshold
Have you heard about the "iceman", Wim Hof, who trained himself to have an incredible tolerance for cold, and holds the Guinness World Record for sitting in an ice bath for 1h52min!?
Neuroscientists suggest that we could train our stress tolerance by deliberately placing ourselves into a situation where adrenaline is increased .
You can do so by engaging in activities such as cold showers and exercises that bring your heart rate up to a bit more than comfortable. Then, try to actively relax the mind while the body is in full output by being mindful in the moment. For example, when you feel like your heart rate has increased drastically during a workout, you could try "observe" your bodily sensation by simply noticing and labeling your bodily sensations as "feeling", and your thoughts as "thinking", but not reacting to them.
Deliberately dilating your gaze by looking around the environment amid a stressful event was also shown to dampen stress. The purpose is to actively calm your mind while your body is in a state of intense activation. Over time, what once felt like a lot now feels manageable. 
Note: if you have underlying medical conditions, please consult a medical professional before trying.
Social connection can take a lot of forms: by connecting with people (romantic, familial, friendship, pets), or by doing things that delight us. Research shows that finding just a few people (even one), a pet, or an activity that you "feel delighted in" is extremely powerful in mitigating long-term stress due to the effects of the following neurotransmitters. 
Socializing promotes the release of 「serotonin」, a natural "anti-depressant" that stabilizes mood and reduces stress.
Chronic social isolation can lead to the release of 「tachykinin」, an "internal punishment signal" molecule that makes us more fearful, paranoid and impairs our immune system. The feeling of being connected (i.e., having long meals with friends and family without intrusions) suppresses tachykinin. [4, 5]
Writing down 3 things you are grateful for every day before bed, however small they may seem, stimulates the serotonin system.
7-9h of sleep daily
Many times, the feeling of stress can simply be due to sleep deprivation. When we lack sleep, our body acts as if it's in distress, releasing more cortisol. To prevent this from happening, consider these tips to improve your sleep. 
We oftentimes forget that we stress about things because we CARE about them. Instead of spending all your time, effort, and energy thinking about how to "get rid of stress", we can choose to utilize the stress response to understand more about what we care, and treat it as an opportunity to reconnect to things that truly matters.
Next time you feel stressed, try asking yourself: What is the stress trying to tell me about my needs? What actions can I take to meet these needs? Maybe your stress is reminding you to socialize more? or sleep better?
 Harvard Health Publishing. (2020, July 6). Understanding the stress response. Retrieved February 8, 2022, from https://www.health.harvard.edu/staying-healthy/understanding-the-stress-response
 Santos-Longhurst, A. (2018, August 31). High cortisol symptoms: What do they mean? Healthline. Retrieved February 8, 2022, from https://www.healthline.com/health/high-cortisol-symptoms#:~:text=Long%2Dterm%20increased%20cortisol%20may,Lack%20of%20energy%2Fdifficulty%20sleeping.
 Wim Hof Method. (n.d.). Benefits of cold showers. Wim Hof Method. Retrieved February 8, 2022, from https://www.wimhofmethod.com/benefits-of-cold-showers
 Huberman, A. (2021, March 8). Tools for managing stress & anxiety - youtube. Retrieved February 8, 2022, from https://www.youtube.com/watch?v=ntfcfJ28eiU
 Dajose, L. (2018, May 17). How social isolation transforms the brain. California Institute of Technology. Retrieved February 8, 2022, from https://www.caltech.edu/about/news/how-social-isolation-transforms-brain-82290
 Banner Health. (2019, February 28). Stress - how sleep can affect stress levels: Banner Health. Stress - How Sleep Can Affect Stress Levels | Banner Health. Retrieved February 8, 2022, from https://www.bannerhealth.com/healthcareblog/teach-me/how-sleep-can-affect-stress