Boost Your Energy & Immune System with Cortisol & Adrenaline

This installment extends a series on hormones that the previous episode had presented as finished. The stated reason for the extra episode is that two hormones, cortisol and epinephrine (also called adrenaline), matter for a large number of biological functions and especially for energy levels and the immune system, a subject the host says he is asked about often. Listeners are told they do not need the earlier hormone episodes, and that any references to them will come with brief background.

The planned agenda covers the biology and mechanisms of cortisol and epinephrine, together with tools aimed at people who struggle to balance stress and energy, people with sleep problems, and people who find it hard to raise their energy during the day and lower it at night. It also promises discussion of how to enhance immune function, how cortisol and epinephrine relate to learning and memory, so-called nootropics or smart drugs that act on the epinephrine system, how caffeine can rewire the brain "for better or for worse," and why comfort foods work, which is meant to clarify food choices for short-term and long-term energy.

Housekeeping notes follow: episodes are timestamped and captioned in English and Spanish by a professional captioning service, so captions take a day or two to appear on YouTube. Listeners are invited to post questions in the comments. Before the main topic, three follow-ups from earlier episodes are addressed: intermittent fasting, why the stomach grumbles, and a way to raise growth hormone that does not involve a sauna.

The previous episode discussed growth hormone and thyroid hormone, and how sauna, exercise and sleep can raise growth hormone within healthy ranges. Growth hormone is described as beneficial for burning body fat and for muscle, cartilage and general tissue health, and as something whose levels fall with age. Fasting was left out at that point because, despite many online claims, the host could not find a study that pointed to an underlying mechanism.

The episode now cites what the host calls "the study," to be linked, showing that fasting does raise growth hormone. The proposed mechanism runs through ghrelin, the hunger hormone that is secreted when blood glucose is low. Ghrelin binds the brain receptor that normally binds growth hormone-releasing hormone, so it can act like that releasing hormone and stimulate growth hormone. (The host notes that both pronunciations of ghrelin are acceptable, thanking listeners who corrected him.)

The size of the effect is given as roughly a doubling of growth hormone levels in the waking state, and unlike sleep-related release it also occurs during the daytime. The claim is qualified: fasting raises growth hormone, but "not to the super levels that taking growth hormone would increase it or that a sauna could increase it." Specific fasting protocols, including how long a fast needs to be, are deferred to later in the episode, with the hint that multi-day or 23-hour fasts are not required.

Stomach growling is attributed to muscle movement rather than, as many people assume, fluid moving around. The stomach is lined with smooth muscle that runs around it in cables, and the stomach periodically closes off at both ends, like a bag with a hose on either end. With food present, these muscles churn the stomach like a tumbler to break up food. Without food, the churning and contraction continue, and that is what produces the growl. The suggested fix for an audibly growling stomach in a quiet meeting or theater is to chew food better.

On heat and growth hormone, the earlier episode reported sauna-driven increases in growth hormone release of anywhere from 300 to 500%, and even 1600%. For listeners without a sauna who asked about hot baths, the answer is that hot baths do raise growth hormone, but the temperatures needed are high enough to risk burns, so no recommendation is made. A hot bath that can be tolerated will produce some release, but less than a sauna, which allows safe entry into a 175 degree or 200 degree environment provided the person is not pregnant, is not a young child, and so on.

A caution accompanies this: anyone experimenting with hyperthermia or hypothermia, including cold baths, ice baths, or hot showers and baths beyond normal comfort, has to be extremely careful and should consult a doctor. Temperature regulation is flagged as the subject of a future episode.

The core framing is that most people want plenty of energy in the day, energy that tapers at night, and an immune system that wards off bacterial, viral and other infections, and that cortisol and epinephrine dominate both processes. Epinephrine and adrenaline are the same molecule; the episode notes the convention of calling it adrenaline in the body and epinephrine in the brain, and uses the terms interchangeably.

Cortisol is a steroid hormone derived from cholesterol, like estrogen and testosterone. That cholesterol can come from the diet or from the liver. The episode calls the link between dietary cholesterol and blood or liver cholesterol "a barbed wire topic": some argue dietary cholesterol has zero impact on circulating cholesterol from the liver, others argue the opposite, and the host says both sides have good data. One problem for the view that diet determines all cholesterol levels is that people with anorexia often have very high liver-produced cholesterol while eating very little or nothing.

Because cholesterol is a precursor that can become estrogen, testosterone or cortisol, cortisol is described as a competitive partner to the sex hormones. Under stress, regardless of how much cholesterol is eaten or produced, more of it is devoted to making cortisol. The episode insists cortisol is still necessary: low levels are undesirable, and cortisol is important for immune function, memory and avoiding depression. The problems arise when levels are too high, or when even normal levels occur at the wrong time of day.

Epinephrine is defended in similar terms. The popular picture of a fight-or-flight relic from the days of being chased by predators is called "all wrong." Epinephrine is presented as a key ally for immunity and protection from infection, and for memory, learning and activating neuroplasticity, with explanations promised later. The verdict on both hormones depends on amount, duration and timing of release:

They're terrific when they're regulated. They are terrible when they're misregulated, and we will give you lots of tools to regulate them better.

The cortisol pathway is summarized briefly. Neurons in the brain make corticotropin-releasing hormone (CRH). CRH causes the pituitary, a gland at the base of the brain about an inch in front of the roof of the mouth, to release ACTH. ACTH causes the adrenals, which sit above the kidneys in the lower back, to release cortisol. Listeners are asked to reframe it: "I would like you to think about cortisol not as a stress hormone, but as a hormone of energy." Its effect is a state in which a person wants to move and does not want to rest or, at least at first, to eat.

Epinephrine is released through several routes. When the mind or body detects a stressor, such as a wound, neurons in the middle of the body called the sympathetic chain ganglia rapidly release epinephrine, likened to a sprinkler system hosing the body. This raises heart rate and breathing rate, can constrict some blood vessels, and widens vessels and arteries that supply vital organs, which is why the extremities get cold under stress as more energy goes to the core. The adrenals also release adrenaline in pulses, anywhere from one to ten, and a brain area called locus coeruleus releases it to create alertness. Listeners wanting the full stress response and stress-regulation protocols are referred to the separate stress episode, since this one focuses on energy and immunity.

The net effect of cortisol and epinephrine is to increase energy, and the first tool targets cortisol timing. It is presented as supporting a healthy state of mind and helping reduce unhealthy states including depression, with the explicit caveat that it will not cure mental illness on its own. The goal is for the day's highest cortisol to occur first thing in the morning. A cortisol increase every 24 hours is described as "nonnegotiable" and "written into your genome," serving to wake a person up and get them moving.