Last week we talked about bad stress and its negative effects on the human body and mind. This week we are going to start looking at good physical stressors and why and how they benefit the body.
A good stress is by definition short lived. It can be something which is perceived as slightly stressful for a longish period - say walking around outside in a T-shirt and shorts in 16 degrees C for 6 hours, or one that is experienced for only a short time but is perceived as very stressful - such as dunking in an ice bath for 2 minutes!
Now to introduce the concept of “Hormesis” which comes from the Greek word meaning “rapid motion”. Hormesis refers to the way in which cells or organisms respond completely differently to stress depending on the length or amount of exposure. To explain - when there is a low level of stress to the body, such as short durations of cold or heat exposure, the body usually responds favourably. At excessive levels (for example, prolonged exposure to extreme cold), we see the opposite effect, with detrimental impact on the body.
One theory about how this works is that the stress activates the repair mechanisms of the body. The resulting repair process then not only fixes the tiny amount of damage from the minor stress but also cleans up any other damage that has accumulated at levels too low to trigger repair mechanisms. “Cold shock” increases norepinephrine, a neurotransmitter in the brain which plays an important role in attention, vigilance, mood and one’s ability to focus. It is often targeted by drugs used to treat depression.
Exposure to cold increases production of mitochondria in adipose and muscle tissue. The mitochondria produce energy in the cell and this extra energy from the new mitochondria helps burn fat. Norepinephrine regulates all of these processes. Walking around in 16 degree cold air for 6 hours causes a 260% increase in norepinephrine. Being submerged in water of just over 4 degrees for 20 seconds causes a 200 - 300 % increase.
RBM3 is a cold shock protein found in the brain. After an exposure to cold, the connections between neurons in the brain are damaged. RBM3 completely regenerates these. This has been shown in hibernating animals such as squirrels and bears. In a study of mice, genetically engineered to get Alzheimers disease, exposure to cold was shown to increase RBM3 and this delayed the onset of Alzheimers.
So - norepinephrine decreases inflammation in the brain and body, reduces pain, improves mood and improves functioning of the brain. We now know that short periods of intense cold greatly increase the amount of norepinephrine in the body. So now we are getting to the reason that being too comfortable isn't necessarily the best for a person. You can start to get benefits today, by turning down the water temperature for 30 seconds at the end of your daily shower, just breathe nice and slow and get out invigorated and ready for your day!