This blog article explores the effects of heat on your system, through some of the latest research into diet, longevity and exercise. We’ll see that heat might just be one of the most powerful exercise tools to emerge to date. But there’s more to health than just exercise. Satisfaction in life comes from a well-coordinated lifestyle. Exercise is a part of this, but Yoga also recognises the need for body and mind to integrate in the maintenance of the individual. This article explores the connection from heat through to Hot Yoga as the means to stimulate, promote and maintain great overall function in body, in mind and in relationships.
What does heat do to your cells?
This is very much a lay-person’s description of what happens to cells when the human body experiences heat. I’ve included the references I found useful – they could be a starting point for your own further research.
Proteins play a very important role in many aspects of cellular function. They are large, complex molecules, with carbon-rich areas that have to be shielded from their surroundings. This means that proteins fold into fascinating 3-D shapes: in this state, they can transport to areas where they’re needed, and when in the correct shape, they can perform their intended functions.
But proteins can get damaged, and sometimes new proteins sometimes don’t fold properly. Mis-shapen or damaged proteins are a problem: they’re not working, and they accumulate, causing a condition called proteotoxicity. Heat, cold and other physical stress can cause these problems. What’s fascinating is how your body responds.
A compound called heat shock factor (HSF) circulates in the fluid between cells. Two things happen in the presence of heat and other stresses.
- Heat shock factor releases heat shock proteins (HSP). These do many things, including: chaperoning healthy proteins to their targets, helping new or misfolded proteins to re-fold correctly, and guiding dead proteins to the protein-recycling areas.
- The remaining HSF migrates to the cell nucleus. It helps protect the nucleus, and causes more heat HSP to be issued.
Even when there is no stress, the HSP are at work helping other proteins and helping cells to stay healthy. Research[A] shows that generating lots of HSP lead to much longer and more youthful life in some invertebrates. Mammals – and humans – are much more complex but research[B] shows that whole-body heat stress triggers the same positive changes as exercise, through the action of HSP.
The question is: can the combination of heat and Yoga practice promote youthfulness, energy and even longer life? To investigate, we need to look a bit deeper at how bodies do growth and renewal.
Your pituitary gland
This is a pea-sized gland in the base of your skull, underneath the brain and behind the bridge of your nose. It has two parts: anterior and posterior (front and back) pituitary. The posterior pituitary is attached to the part of the brain that controls pituitary activity. The anterior pituitary is connected to the brain by very short blood vessels and consists of gland cells.
The highlighted area (centre) shows the pituitary gland attached to the bottom of the hypothalamus at the base of the brain. Image reproduced from http://www.yourhormones.info/glands/pituitary-gland/
It’s called the master gland because the hormones it produces control so many different body processes. It senses the body’s needs and sends chemical (hormone) signals to different organs and glands all around your body to regulate and maintain an appropriate environment. Through production of hormones, and by issuing some hormones produced elsewhere in the brain, the pituitary gland controls lots of vital processes such as metabolism, growth, sexual maturation and reproduction, blood pressure and more, and aspects of behavior in relationships.
What hormones does your pituitary gland produce?
The anterior pituitary gland produces the following hormones and releases them into the bloodstream:
- Adrenocorticotropic hormone, which stimulates the adrenal glands to secrete steroid hormones, principally cortisol
- Growth hormone, which regulates growth, metabolism and body composition
- Luteinising hormone and follicle stimulating hormone, also known as gonadotrophins. They act on the ovaries or testes to stimulate sex hormone production, and egg and sperm maturity
- Prolactin, which stimulates milk production
- Thyroid stimulating hormone, which stimulates the thyroid gland to secrete thyroid hormones.
There are also some hormones that are produced by the hypothalamus and then stored in the posterior pituitary gland prior to being released into the bloodstream. These are:
- Anti-diuretic hormone, which controls water balance; the amount of water in your blood affects blood pressure
- Oxytocin, which stimulates uterine contractions during labour and milk secretion during breastfeeding, and generates loving/caring feelings. More on this later, in the section on Ajna chakra.
Growth hormone enters the liver, where it stimulates the production of insulin-like growth factor (IGF). It’s called insulin-like because of how cells react. Cells have receptors for chemical messengers: the receptors for insulin are very similar to the receptors for IGF. When IGF binds to the correct receptor, it has very positive effects. For instance, it helps neurons survive, encourages muscle development, protects cartilage cells, and is associated with activation of cells that maintain bones. And since it can bind to the insulin receptor, it can also complement the effects of insulin.
Research with invertebrates[C] into IGF shows it plays a major role in longevity. Perhaps surprisingly – reducing growth hormone and IGF activity in some roundworms increased lifespan more than twofold and the worms remained active and youthful much longer than normal.
Mammals are much more complex animals, and it’s not clear that just playing with growth factor is going to generate similar increases in longevity and youthfulness. However, it’s long been known that dietary restriction[E] increases the lifespan of mammals (as long as the food eaten is of good quality and there’s no danger of malnutrition). The mechanism has been researched[C][D], and – in brief – the following was found:
- Age-related drops in HSP were reversed by restricting calories.
- Human studies show calorie restriction effective against obesity, insulin resistance, inflammation, oxidative stress, and other ailments. It lowers the risk markers for all sorts of serious diseases. It doesn’t reduce total and free IGF levels in healthy people unless protein intake is also reduced, raising the possibility that protein restriction alone may provide some benefits, perhaps because HSP levels continue to be strong. In the detailed research papers, you will also read that calorie restriction also activates heat shock transcription factor 1, a special chemical that plays a key role in the replication of molecules.
The graph shows that appropriate restrictions on calorie intake, that do not risk malnutrition, lead to substantial increases in lifespan for mammals. Reproduced from (reference 5 below) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3607354/
Creative people are referred to as “left-brained”, and practical people as “right-brained”. We naturally take left and right to represent pairs of opposites, like female and male, subtle and direct, moon and sun etc. In between two opposites is the neutral ground, from which both sides are visible. The one that can see both, but doesn’t favour either, is the best leader – the leader that allows the right thing to happen at the right time.
Ajna means command. It’s associated with the pituitary gland, because the pituitary issues the chemical messengers that orchestrate and coordinate 9 (some sources say 10) other major glands. These, in turn, collectively affect the function of the whole body. Furthermore, the pituitary both produces and secretes growth hormone and prolactin. Growth hormone stimulates growth in children and maintenance in adults. Prolactin governs milk production, and affects overall behavior, the immune system and the reproductive system. Finally, the hypothalamus generates oxytocin but it’s issued into the bloodstream from the (posterior) pituitary. Oxytocin regulates social interaction, sexual reproduction, and has a role in bonding, empathy, generosity, and orgasm. When we hug or kiss, oxytocin increases: oxytocin is often called “the love hormone.” Oxytocin is the hormone that underlies trust, and is an antidote to depressive feelings.
Taking all of this together, the pituitary plays a major role in the overall function of the whole person. If everything is working well, it has the potential to exhibit the impartial commanding neutrality of ajna chakra.
Good function in ajna chakra is more than physical health. In the same way that the pituitary mediates important physical functions, ajna correlates our psychological and emotional experiences as well. From this point of view the good and bad aspects of life seem to suddenly fit together like a complete tetris screen, and their effects vanish in a similar way to a complete row of tetris blocks. The effects are still felt, but the student gets to opt out of getting caught up in them. Living well at ajna chakra means being able to integrate events and experiences into a whole and sustainable life.
We covered a lot of science and research in this article. We’ve learned that heat shock proteins (HSP) play a vital role in overall health, and that watching calories promotes health in all sorts of ways. It maintains HSP levels as we get older – without affecting growth hormone. Everybody recognises that exercise is a good thing generally, and we’ve seen that exposure to heat alone produces the positive body effects of exercise.
It seems like any exercise in the warmth is going to be great for your body – if you are careful and eat the right amount of good food as well. Hot Yoga offers this and more, as its holistic practice style stimulates ajna chakra.
- Specific protein homeostatic functions of small heat‐shock proteins increase lifespan https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4783350/
- Heat Stress and Cardiovascular, Hormonal, and Heat Shock Proteins in Humans https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3418130/
- Insulin, IGF-1 and longevity, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3295030/
- Expression of heat shock protein 70 is altered by age and diet at the level of transcription. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC359684/
- Dietary Restriction, Growth Factors and Aging: from yeast to humans https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3607354/