Heat Exposure: Eustress Vs Distress!

Here are my notes from a recent podcast.

In this episode, it describes the mechanisms by which deliberate heat exposure impacts body temperature, metabolism, heart health, hormone production, exercise recovery, cognition, mood, and longevity.

Benefits of Heat Exposure

Lower risk of:

• cardiovascular disease,
• sudden cardiac death,
• coronary heart disease,
• hypertension,
• stroke,
• neurodegenerative diseases like dementia or Alzheimer's,
• muscle atrophy.

It also allows:

• Better physical performance and recovery,
• Increases in metabolism,
• Enhancement of hormones like Growth Hormone and Cortisol
• Excretion of toxins,
• Improvement of Heart Rate Variability,
• Treatment for Depression and a better mood overall.

 

Mechanisms

When you get into a hot environment, your shell senses the heat and activates the neurons in the POA, which in turn activates mechanisms in the Autonomic Nervous System. Some physiological responses to sauna:

• The skin heats first and then changes in core body temperature occur,
• vasodilation (more blood flow),
• plasma volume,
• Heart Rate increases.

These responses look a lot like cardiovascular exercise. You are basically getting a cardio workout.

Hormone Effects of Sauna

Tool to reduce stress:

Study: Four sauna sessions of 12 minutes each, at 90°C. After that, they did a 6-minute cool water immersion or cold shower→ Results: Cortisol decreased.

Growth Hormone :GH is secreted from the pituitary. The signals arrive from the neurons in the hypothalamus.GH impacts metabolism and growth and repair of cells.At around 30 years old, the levels of GH release start to decrease

Improvements in Mood and Mental Health

Sauna use can sensitize the receptors of the opioid system. It improves our capacity to feel good and experience pleasure in other situations.

Endorphins are released in response to stressors. The endorphin system is not just about feeling good, it’s also about feeling bad.

Dynorphins: they make us feel worse in response to stressors. When we get into a sauna dynorphins are released (discomfort we feel). Dynorphin binds to the kappa receptor. In consequence, the brain produces more mu-opioid receptors, sensitizing them to endorphin and future endorphin exposure.

Elevating the body temperature also has a very robust anti-depressant effect.