Mitochondrial function: extreme temperatures and their health benefits

If you are constantly researching and interested in natural alternatives to achieve or maintain optimal health, you will have come across the topic of mitochondrial function. Basically, mitochondria are organelles inside cells (some more, others less) but they are responsible for supplying the energy necessary for cellular activity and respiration. To make a long story short, they are the primary source of energy for our body.

When mitochondria do not function optimally, the body's ability to produce energy is distorted. To have the energy we need at all times, the body must eliminate unused mitochondria and produce new ones, which is called mitochondrial biogenesis . There are some strategies to achieve this:

• Exposure to extreme heat and cold
• Exercise
• Intermittent fasting
• Ketone cycles
• Some foods and supplements such as resveratrol

All these strategies stimulate the production of peroxisome proliferator-activated receptor gamma and co-activator a1 (PGC-a1), which is the main factor in mitochondrial biogenesis.

Let's see how physical exposure to extreme temperatures for cycles of several minutes benefits certain organs and bodily functions.

Exposure to extreme heat and cold

Dr. Rhonda Patrick has been studying hyperthermic conditioning (both extreme heat and cold) for several years and has a number of videos presenting the many benefits of both heat and extreme cold.

For example, the use of hot baths, steam or saunas that raise the body's internal temperature helps activate genes that are important for improving the function of intracellular heat shock proteins (HSPs).

Heat stress has been associated with

• The increase in athletic endurance
• Prevention of atrophy during muscle disuse (and regeneration of the muscle when reused)
• Improves insulin sensitivity by increasing glucose receptors in muscle cells
• Increases BDNF and norepinephrine (BDNF is a protein that stimulates the growth of new brain cells and norepinephrine is a neurotransmitter associated with attention and concentration)
• Longevity

As for cryotherapy (entering a cold environment), and immersion in ice-cold water, apart from benefiting the metabolism, muscle relief, and athletic performance, it produces one of the most interesting effects that takes place in the brain.

One of the most powerful physiological responses to cold exposure is the release of the hormone norepinephrine into the bloodstream as well as the locus ceruleus of the brain. Norepinephrine, which is also a neurotransmitter, is manifested in levels of attention, concentration, cognitive ability and mood. In the bloodstream, it increases vasoconstriction and according to Dr. Patrick, norepinephrine is accompanied here by dopamine.

Just as exposure to extreme heat in a sauna activates heat shock proteins, exposure to extreme cold does the same, but there is also a type of protein that is specific to this stimulus called cold shock proteins.

There is one particular cold shock protein known as RNA binding protein 3 (RBM3). This protein is found in the brain, heart, liver and skeleton and is strongly activated by just a little exposure to cold.

Specific benefits of exposure to freezing temperatures or cryotherapy

• Reduces inflammation : the purpose of inflammation is to eliminate the initial cause of cell damage, eliminate dead cells and tissues affected by the aggression to which they have been subjected and initiate the tissue restoration process. However, when inflammation gets out of control (due to causes other than physical aggression such as poor eating habits, sedentary lifestyle, etc.) it has been identified as the main driver of aging and the diseases related to it.

Norepinephrine inhibits the inflammatory pathway by decreasing tumor necrosis factor alpha (TNF-alpha), a very potent molecule that increases inflammation.

Norepinephrine production has also been shown to decrease other annoying chemicals such as macrophage inflammatory protein-1a, produced by immune cells that play a major role in rheumatoid arthritis.

• Whole body cryotherapy and arthritis, in experiments with patients who endured a temperature of -110 °C for 2-3 minutes in sessions 3 times a week, a great reduction in pain was identified.

 

• Immune function, the immune system plays another important role in the aging process as it is associated with the reduction of immune cells. But how does cold affect the reserve of immune cells? It was shown that immersion in cold water 3 times a week for 6 weeks significantly increased the number of lymphocytes. ( 1 ) Another study showed that physical exposure to a temperature of 5 °C increased the number of white cells including cytotoxic T lymphocytes which is a type of immune cell that destroys cancer cells. ( 2 )

Cold, weight loss and thermogenesis

Dr. Rhonda Patrick in her study on cold stress explains that ice baths have become popular due to the weight loss effects of cold. One of the body's ways of responding to cold is by stimulating the metabolism, not to produce energy in the form of ATP (adenosine triphosphate), but to warm the body and in the process, burn fat. This process is known as thermogenesis.

There are two types of thermogenesis, one is shivering thermogenesis where muscle contractions increase metabolic energy. Non-shivering thermogenesis occurs in adipose tissue and is responsible for the “fat burning” effect once the body adapts to the cold.

Thermogenesis without shivering and brown adipose tissue. This process is regulated in part by the hormone norepinephrine, which as we already know is induced by exposure to cold, depending on its intensity and exposure time. This is where the uncoupling protein 1 is expressed, which, you should only know, produces a greater number of mitochondria in adipose tissue, making it metabolically active.

Exposure to cold increases the antioxidant activity of enzymes. One of the side effects of burning stored fat for energy is the production of reactive oxygen species (ROS) that can damage even the DNA of the cell. This is normal, but it is important to be able to counteract this damage.

Well, it seems that exposure to cold, which functions as a hormetic tensor, that is, a low stimulation to an environmental factor that is harmful in high doses and that induces an adaptive response, can also activate antioxidant genetic systems that are much more powerful than any antioxidant supplement. ( 3 )

Cold shock, muscle mass, performance and recovery

 In the context of exercise, exposure to cold has two variables:

• The type of exercise performed
• Timing of cold application in relation to exercise

Synchronization

Immediately after exercise, there is a spike in the production of pro-inflammatory cytokines, i.e. molecules that activate immune cells involved in tissue repair. Inflammation and reactive oxygen species are necessary for the activation of mitochondrial production and muscle growth.

There is then an anti-inflammatory response that occurs approximately one hour after exercise, at which time some anabolic hormones such as IGF-1 (insulin-like growth factor type 1) increase, the decrease in its signaling has been shown to slow down the degenerative process of aging and extend the life of a wide range of organisms, possibly including humans ( 4 ).

So for some exercises, cryotherapy and cold water immersion immediately after exercise are not very suitable, while for others it can be beneficial.

Types of exercise

Remember that physical activity puts stress on the body and in response, the body activates genes and processes that create resistance to that stress. What is important to understand here is that adaptation occurs depending on the type of exercise. The stress can be aerobic (resistance training), mechanical (strength, weights) or a mix of both (plyometrics).

Strength training

Several studies have shown that performing cryotherapy or cold water immersion one hour after exercise is not very beneficial as it inhibits muscle hypertrophy.

Endurance

In the case of endurance activities such as athletics, the consequences of cold water immersion and cryotherapy are more positive in tests carried out more than one hour after the exercise has finished.

Cold in this sense increases the production of mitochondria and this affects aerobic capacity. Thus, elite athletes subjected to 1, 24, 48 hours of cryotherapy after doing speed sprints increased their speed and strength by 20% as soon as two days after this practice. ( 5 )