Cortisol: Dr Jekyl and Mr Hyde

Many of us know that cortisol is the ‘stress hormone’ and assume it’s all bad. Actually, cortisol is a complicated cat, essential for survival but detrimental to survival in excess. Let’s break it down.

Cortisol is a naturally circulating hormone that follows a rhythm. When we are healthy, cortisol levels rise in the morning just before getting up, and the level peaks 30-40 minutes after waking. It’s a natural stimulant to get us going in the morning, kicking off metabolism by releasing stored glucose and freeing fatty acids and amino acids to fuel the body. The adrenals are stimulated to produce epinephrine and norepinephrine which increase cardiac output and vasodilation in muscles, and boom! We’re ready to rock and roll for the day.

Cortisol usually runs on an inhibitory loop, meaning when the concentration in the blood is too high, secretion is reduced. As the day progresses, cortisol levels drop, until late afternoon when we get a spike (our ‘second wind’). Levels then decrease through the evening to bottom out around midnight, which why we tend to want to be sleeping then.

So far it seems like the good guy right? It gets a little better: cortisol is fat burning. This means if we add a little stress, like exercising, while fasting (not for days on end, just on an empty stomach), then we go into fat burning mode. Eating soon after, taking Branch Chain Amino Acids or protein helps this effect, as does lowering cortisol levels post-exercise. We can lower cortisol with leisure walking, sleep, massage, meditation, laughing, physical affection, essentially anything relaxing. Still sounds good right? Cortisol is so essential in helping us deal with stress in an appropriate way, it even reduces inflammation! This reduction of inflammation is our first hint at the Mr Hyde side of cortisol.

Elevated cortisol when combined with insulin, ie: if you’ve eaten something sugary while stressed, increases fat storage. Cortisol can contribute to cravings and also hypothyroidism. The metabolic attributes of cortisol turn on us and we wind up with reduced lean muscle mass and increased insulin resistance. Insulin resistance can then lead into Diabetes type 2, completely messing with our ability to regulate blood sugar levels. It can also lead to weight gain.

Cortisol reduces inflammation and the immune response leaving the body more susceptible to illness. Excess cortisol levels have been shown to decrease Hippocampal volume, the part of the brain associated with memory. It decreases our REM sleep, the important part of our sleep cycle for replenishing the body. Cortisol also increases our awake time which can lead to insomnia, chronic fatigue and mood disturbance.

Cortisol is indeed a Dr Jekyl and Mr Hyde hormone.  A little is normal, healthy and essential – the problem lies in excess. Chronic stress, sleep deprivation, inflammation, alcohol and coffee will increase the circulating cortisol levels and throw the system out of whack. Reduce stressors on the body, deal with chronic stress and your body will return to its healthy cortisol rhythm.

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