Here we explore why some physical stress is actually vital for optimizing your overall health!
Although many people in the busy western world suffer from excessive mental stress, be it their finances, relationships or demanding work deadlines, a certain level of stress can actually be beneficial for our physical and mental health. We are constantly being taught that stress is bad and that we need to minimize the stress in our lives. Although I agree that stress in the form of excessive worrying and mental overexertion will often cause more harm than good, it is important that we evaluate the role of physical stress and our body's ability to adapt. Hormesis is by definition, the process by which exposure to small amounts of substances or conditions that stress our body lead to greater overall resilience and ability to handle periods of high stress.
Types of Hormesis
Diet rich in Polyphenols (Oxidant Stress)
What are polyphenols you may wonder? Polyphenols are compounds found in plants that give them their colour and contribute to the integrity of the plant. In other words; fruits, vegetables, legumes, teas, coffee, chocolate, red wine, seeds, and medicinal herbs all contain polyphenols.
Some popular studied polyphenols include curcumin (from turmeric), resveratrol (from red wine), quercetin (many fruits and vegetables) and EGCG (from green tea). However, there are so many more.
Although some polyphenols may show promise when taken in an extract supplemental form, the majority are best taken by eating polyphenol rich foods, rather than a capsule. Many studies that tried to extract these beneficial compounds from plants showed negative health outcomes. Why might that be? Lets dive in to how these compounds work!
Although commonly marketed as anti-oxidants, the majority of these compounds are actually pro-oxidants. They work by a pathway in our body's called the Nrf2 pathway, which activates genes that are involved in detoxification of chemicals and antioxidant defense(1, 2, 3). They trigger our body's to produce an anti-oxidant effect, strengthening our ability to respond to stressors, rather than putting out the fire themselves.
Exercise (Physical Stress)
Most of us are aware that regular physical activity is important in the prevention of a multitude of chronic diseases included alzheimer's, diabetes, and cardiovascular disease. But how is it that exercise improves our health and longevity?
Much like with polyphenols, exercise has been shown to improve the oxidant/anti-oxidant balance within our body. A system well known to prevent our cells from damage and aging. Another very important roll of physical exercise is the up-regulation of mitochondria. This means that as the body undergoes the physical stress associated with moderate exercise, it increases the amount of mitochondria in order to provide sufficient energy for the physical demand on our body (4). Our understanding of the role of mitochondrial in the body has expanded. Mitochondria are no longer simply the 'powerhouse' of the cell, as most of us learned in grade 12 biology. Mitochondria are also involved in cellular respiration (utilization of oxygen and removal of CO2 waste products), calcium homeostasis (vital for muscle, nerve and cardiovascular function), promoting cell growth, and Apoptosis (programmed cell death of a dysfunctional or mutated cell for cancer and disease prevention).
It has been shown that our mitochondria decrease as our body ages. By exercising regularly, we are improving our longevity, energy, and preventing chronic diseases to keep our body young and healthy.
Intermittent Fasting (Nutritional Stress)
Intermittent fasting is a model of eating all your calories in an 8 hour window and fasting for 16 hours of the day. This usually involves a person having their last meal before 8pm and resuming eating at noon the next day. This method of eating has been gaining popularity for its role in weight loss, and improving fatigue. Lets look at how narrowing your eating window impacts your body.
When we fast, we decrease insulin levels in the body and increase levels of norepinephrine (a stress hormone) and Human Growth Hormone (HGH). Insulin is responsible for storing sugar from food as fat. When we fast, it actually improves insulin sensitivity, giving your body a chance to mobilize some of the glucose that has been stored in your fat cells to use as fuel (5,6,7). By improving insulin sensitivity, it also helps to prevent the development of type 2 diabetes (8). As we age we produce less HGH. Intermittent fasting increases levels of HGH in the body, which improves weight loss while maintaining muscle (9,10).
It is our mitochondria that convert fat into energy by a process called beta-oxidation. When we fast, we allow our body to utilize this process and become 'fat adapted'. It has become uncommon for people to feel hungry with the amount of snacks and quick food options at our disposal. When we do not allow our bodies to feel hunger, we are preventing the utilization of fat for fuel. This in turn results in our body storing both sugar and fat from our diet into fat in our body, resulting in weight gain and difficulty with weight loss.
In addition to weight loss, fasting also appears to induce 'autophagy'. This is a cleaning process by which your body recognizes damaged or dysfunctional cells and breaks them down. By removing these waste products in the body, you are preventing the occurrence of chronic diseases (11,12,13), improving the regeneration of healthy cells, and decreasing inflammation in the body(14)!
Heat/Cold Exposure (Temperature Stress)
When discussing heat stress, I will be focusing on dry sauna use in particular. The amount of health benefits from heat stress makes this form of hormesis one that I would highly recommend to everyone (unless you are pregnant or late stage of any disease)!
Dry sauna use has been shown to increase longevity and lifespan. It does so by activating heat shock proteins (HSPs), which increase autophagy, initiate cell repair, and promote high levels of glutathione, a strong anti-oxidant in within our body(15,16). In simple terms, HSPs clean up damaged cellular debris and waste, and keep our cells from aging due to oxidative damage. Higher levels of HSPs in the body are associated with longevity(17).
Interestingly, sauna use has also been shown to activate a particular gene known to be present in those who are able to attain exceptionally old age(18,19). This is likely linked to the gene's ability to initiate DNA repair, improve immune function and promote stem cell activation (20,21).
Heat stress also plays an important role in detoxification. The ability to sweat is vital for the removal of toxins from the body. Research has shown that certain dangerous heavy metals are best excreted from the body via sweating than any other excretory mechanism (urine or feces) (22,23,24). When you sweat, you promote your body to excrete heavy metals like mercury, cadmium, arsenic, and lead, but it is not only heavy metals that we excrete via our sweat. Researchers have found PCBs, BPH (endocrine disrupting chemical found in plastic), DDT (banned pesticide), fluoride and residues from prescription drugs in measurable amounts from human sweat samples.
The ability to produce copious amounts of sweat is often not experienced by everyone. Regular sauna use showed an increase in the ability to detoxify by producing more sweat than first time users. It also showed improvements in those with all chemical sensitivities, largely linked to increase in overall toxic load and therefore decreasing toxic burden(25).
Because of the fact that you are covered in toxins, it is very important to take a cold shower following sauna use for 2 reasons. First, in hydrotherapy, one should always finish a treatment with cold to help promote optimal circulation and to close the pores so that you are not absorbing any toxins. The second reason is that when we shower in heat, the steam promotes many of the toxins to get reabsorbed in the lungs. Interestingly, our body readily absorbs more toxins via inhalation than via consumption. This is why it is important to filter your shower water so that are you not inhaling chlorine and other volatile organic compounds.
Another important health benefit of heat stress is the effect on the nervous system. Studies showed that sauna use increases brain derived neurotropic factor (BDNF). BDNF promotes the growth of new brain cells and increases neuroplasticity which is involved in learning and long-term memory (26).
There are so many more ways in which heat stress via sauna use has been shown to improve our health. To spare you hours of reading I will list some of the other health benefits that we have not talked about. 1. Lowers inflammation and increases recovery time post workout
2. Increases Immune system function to help you fight infections better
3. Improves cardiovascular function and prevents cardiovascular disease
4. Improves pain and helpful for patients with Fibromyalgia
5. Promotes weight loss and increases muscle growth
6. Prevents a number of chronic diseases (alzheimer's, diabetes, Lung disease, cardiovascular disease)
7. Good for skin health (via its role in detoxification)
If you are using a sauna regularly, it is important to remember to stay hydrated!!! You may also want to consider taking electrolytes before or after the sauna.
Similar to heat stress, cold stress has a number of health benefits. Here are a list of benefits of cold exposure supported by research:
1. Aids in fat loss & obesity
2. Improves muscle recovery post workout
3. Strengthens the nervous system
4. Improves blood sugar regulation
5. Helps heal injuries
For more information on how cold exposure does these 5 things and for the research behind it, click here!
So to summarize... skip breakfast, eat a variety of plants, exercise regularly & most importantly, relax in a sauna!
This is such an informative piece. It's so helpful to understand the science behind some of these practices before adopting them as a lifestyle. Thank you!