We have been on a vacation to Dubai this August. All travel sites do recommend to not visit Dubai in the summer months due to the extreme heat. This heat was actually the main reason why we chose Dubai as the destination. The week we spent there we had about 42° Celsius on average. How good this heat makes me feel got me interested in doing more research on the exact effects of heat on the body. Since August I have dedicated a good chunk of my study time on heat and its effects. Some of the most interesting findings I found will be put together in a short article series with the title "Dubai, Heat & ...". With this first article being about heat and the brain.
When considering brain function one of the first tasks is how to elevate neurogenesis which is the process of making new brain cells. Physical exercise is most known for inducing release of proteins from nerve cells known as neurotrophic factors, which activates brain stem cells to produce new neurons, such as brain-derived neurotrophic factor or BDNF.
What is BDNF?
BDNF acts on certain neurons of the central nervous system and the peripheral nervous system, helping to support the survival of existing neurons, and encouraging the growth and differentiation of new neurons and synapses.In the brain, it is active in the hippocampus, cortex, and basal forebrain—areas vital to learning, memory, and higher thinking. BDNF is especially important for long-term memory. Although the vast majority of neurons in the mammalian brain are formed prenatally, parts of the adult brain retain the ability to grow new neurons from neural stem cells in a process known as neurogenesis. Neurotrophins are proteins that help to stimulate and control neurogenesis, BDNF being one of the most active. Which makes BDNF one of the most important aspects of brain function and brain health.
BDNF & Muscle
Next to physical exercise which has been shown to elevate BDNF significantly (1). When it comes to brain function and biological health the two main factors involved are muscle mass and muscle strength – click here for a full article on this research. Both, muscle mass and muscle strength highly depend on the neuro-muscular system therefore brain function and health. Specifically BDNF also expresses itself in your neuromuscular system where it protects neuro-motors from degradation. The neuromotor is the most critical element in your muscle. Without the neuromotor, your muscle is like an engine without ignition. Neuro-motor degradation is part of the process that explains age-related muscle atrophy.
BDNF & Heat
Next to physical exercise there is also research to points out that heat can significantly increase BDNF. Especially exercise in heat increases BDNF compared to exercise done at lower temperatures. In the study eleven well-trained males exercised in an environmental temperature of 18°C or 30°C. Exercise triggered a greater increase in BDNF at the 30° compared to 18°(2). Which shows that heat aids the BDNF release and this way brain function.
Prolactin & Heat
Further research has also shown that heat will increase prolactin as well (3), which has shown to promote myelin growth. Myelin is the insulation of many nerves that helps with speed of neural transmission and therefore motor controll, attention span, focus and more. So myelin is helping your brain to function faster and repair nerve cell damage. Even the so-called "runner's high," the boost in endorphins, and well-being, that's often felt after exercise may be related to heat stress, as one animal study revealed that heat stress from exposure to a sauna increases endorphins significantly (4 ).
The take-home message: Heat from 30° about to a sauna has potential beneficial effects on brain function. Exposing yourself to warmer climates and regular sauna use is therefore a great addition to maintain and increase brain function.