A wikipedia of Dr. D'Adamo's research

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Stress and ABO Blood Groups


See Also

  • [Dopamine Beta-Hydroxylase (DBH)]?
  • [Stress and ABO Blood Groups]?
  • [Dopamine Beta Hydroxylase and ABO Groups]?
  • [Cortisol and Catecholamine Response Differs By ABO Group]?

The chemistry of stress

Under circumstances of physiological or emotional stress, the body protects itself by shifting the relative balance of our nervous system and by rapidly secreting specific stress hormones such as cortisol, adrenaline (sometimes called epinephrine) and noradrenaline (sometimes called norepinephrine). While these effects are not ideal over the long term, it is important to recognize that the complex physiological responses to stress are intended to reestablish homeostasis or balance. These responses are our means of adapting to a challenge.

Basically, the adrenal glands are an extension of the sympathetic nervous system. In response to stress these glands release several different chemicals into your blood stream. These messengers provide another level of communication between your nervous system, your hormonal system, and your other internal systems to provide further direction as to how they should act in response to stress.


The first class of the messenger molecules made by the adrenal glands are catecholamines. There are two catecholamines released from the adrenals in response to stress: Epinephrine (commonly called adrenaline) and norepinephrine. Clearly this response is very useful under some circumstances. But a prolonged duration of time in this mode will come at a cost.

Although blood type A responds to stress by releasing a lot of adrenaline, they can eliminate it very quickly. Blood type O can actually have more problems with catecholamines, when they do produce a large amount in response to stress, it can take them a while to eliminate them and their effects.


Another critical hormone to consider is cortisol? which is also made and released from your adrenal glands. Cortisol is in a class of chemicals called glucocorticoids. Most people have actually used a glucocorticoid at some point in time. Medicines like hydrocortisone or prednisone are examples of these glucocorticoids.

While the catecholamines can be thought of as more of a short-term solution to stress, cortisol is more of a long-term response. Cortisol is a catabolic hormone, meaning it will function to break down muscle tissue and convert the proteins from this muscle tissue into energy. This hormone is often portrayed as the enemy of body builders since it acts to break down their hard-earned gains in muscle mass.

Cortisol is considered to be such a reliable indicator of stress upon a system that many physiologists define stress as an event that elicits increased levels of cortisol. These include exposure to cold, starvation, bleeding, surgery, infections, pain or injuries, and too much exercise just to name a few. Even your mental state can induce the increase of this hormone. A critical, but often overlooked, piece of the puzzle influencing the release of cortisol to stress is actually your blood type. But before looking at this connection lets explore cortisol and stress a bit further. It is in the arena of cortisol that blood type A's are hit the hardest and blood type O's tend to be spared.




The Complete Blood Type Encyclopedia is the essential desk reference for Dr. D'Adamo's work. This is the first book to draw on the thousands of medical studies proving the connection between blood type and disease.

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