Thyroid problems and blood pressure connection
Blood pressure can be affected by many factors. Thyroid hormone imbalances affect blood pressure greatly. In my previous post, I had talked about body temperature being indicative of thyroid dysfunction. Blood pressure is also a strong indicator of thyroid function for people with thyroid hormonal imbalances. It is important to observe body signals as they are number one indicators that something is not right with thyroid hormones for people with thyroid issues.
I remember one day driving to my doctor for a check- up visit in heavy traffic while munching on chocolate coated coffee beans. I was almost late and when I saw my doctor, I was a bit flustered. I had a busy, stressful day. During a consultation with my doctor, she measured my blood pressure and it was through the roof. I do not know about you but I always get a bit nervous when my doctor is about to measure my blood pressure despite trying to stay calm and breathing deeply. Just feeling stressed, uncomfortable can raise blood pressure by itself. Blood pressure often fluctuates throughout the day. However it is not the temporary spikes of blood pressure we have to worry about but the sustained, chronic high blood pressure. Some people are not aware of their raised blood pressure. Blood pressure problems may be silent. For me, headaches, general tension, pins and needles in my arms and whooshing sound in my ears in the evening points to a possible blood pressure problem and possible hormonal imbalance. During my consultation that day, I had found out that my TSH value was 0.22, too low for me. I operate best at value of 1.7 so the dose of my hormonal replacement was slightly reduced and blood pressure came down. I also stopped drinking coffee and went to have decaffeinated variety and no more chocolate coated coffee beans!
I will explain how thyroid hormones affect blood pressure. When your doctor measures your blood pressure with a blood pressure monitor (sphygmomanometer), she or he inflates a cuff on your arm to collapse and then release the brachial artery under the cuff. A doctor usually uses a manual sphygmomanometer and listens to your brachial artery through a stethoscope. However there are digital blood pressure monitors available as well. When the pressure is released slowly from the cuff, the doctor listens to a first whooshing sound in your artery. This sound represents your systolic reading, it is when the blood starts flowing again in the artery, forced through by a heartbeat. Then as the cuff falls farther, the sound stops and the reading of diastolic blood pressure is taken at that moment. That reading represents the blood pressure in your artery between the heart beats, at the resting phase of the cardiac cycle. Therefore, blood pressure represents the force of blood against the arterial wall. The systolic pressure shows the power of the heart contraction and the force of blood being pumped in the artery. The second diastolic pressure represents the dilation and flexibility of the arteries.
Normal blood pressure is around 120 (systolic) and 80 (diastolic), 120/80.
High blood pressure is 140/90 or above.
The operating centre for blood pressure is present in the brain stem where signals from the body are processed. Blood pressure system is regulated by renin- angiotensin- aldosterone system and by sympathetic nerves and hormones adrenaline and noradrenaline.
While, there are many factors which can influence blood pressure, I will concentrate on thyroid dysfunction specifically in this post. Both the sympathetic and hormonal systems are deregulated in thyroid dysfunction. It has been suggested in scientific literature that there is a disconnection in the renin-angiotensin-aldosterone system in both hyperthyroidism and hypothyroidism as the functioning of kidneys is affected. Thyroid and renal function are interrelated.
People with Graves; disease have an increased rate and depth of respiration as well as higher blood pressure and a rapid heartbeat. There may be over 100 heart beats per minute. The systolic blood pressure is usually considerably higher than 120 and more raised than diastolic. Normal blood pressure is around 120 (systolic) and 80 (diastolic). In hyperthyroidism the reading for blood pressure is generally (≥140/<90 mm Hg). It is called systolic hypertension. It is also called secondary hypertension as thyroid hormones are the underlying cause of the high blood pressure. The pulse pressure is the difference between the systolic and diastolic pressure. The normal resting pulse pressure is therefore around 30-40 mmHg. People with GD have widen resting pulse pressure.
Too much thyroid hormones in blood increases metabolic rate. The heart and cardiovascular need to adjust. The excess of thyroid hormones increases the use of oxygen in the body. The sympathetic nervous system (SNS) is dominant in Graves’ disease, activated by excessive thyroid hormones. It is a system which is normally responsible for a ‘fight of flight’ body response to a dangerous and stressful situation and it releases catecholamines- epinephrine and norepinephrine from adrenal glands to accelerate the heart rate and increase blood pressure. The effects of hyperthyroidism include increased cardiac output, contractility, tachycardia, widened pulse pressure and dilation of peripheral blood vessels. Heart often goes into a ‘marathon run’. Heart related problems, such as palpitations (strong and fast beating of the heart) is a common symptom of Graves’ disease. This can also cause irregular heartbeat sometimes. Atrial fibrillation (type of a heart arrhythmia) can be seen.
Thyroid hormones increase other hormones such as aldosterone (from adrenals) and renin (from kidneys) secretion. This also increases blood volume and blood pressure by causing water to be reabsorbed along with sodium while more potassium is excreted in urine. Thyroid hormones and kidneys stimulate the development of red blood cells which also increases blood volume. Kidneys increase in mass with hyperthyroidism. Long term hypertension may lead to heart disease as it strains the heart.
Generally, hypothyroidism can in time significantly increase diastolic pressure, raising it above 90 mm Hg. It is often called hypothyroid hypertension. This is due to the fact that over time, continuous hypothyroidism causes changes to blood vessels, they become ‘stiff’ and constricted. The systolic blood pressure reading may also become elevated. However, there is a narrow pulse pressure.
Hypothyroidism is very stressful for the body. The body has to increase blood pressure to fight the slow metabolic rate and consequences of negative effects of low thyroid levels. It tries to do it with other hormones and molecules. The sympathetic and adrenal system is activated. The levels of adrenal norepinephrine were found to be elevated in hypothyroidism. Adrenal aldosterone hormone imbalance is connected to hypothyroidism and its increased levels may result in a constriction of blood vessels and elevated diastolic (bottom number) blood pressure. Cortisol hormone levels spike at times, especially in the morning in order to raise blood pressure and to increase the heart rate. Aldosterone hormone can spike about 2am. I had found myself awake at 2am with heart palpitation when I was on a levothyroxine hormonal replacement only. I discovered that if I had something to eat in the middle of the night, my palpitations would stop. Aldosterone hormone increases blood pressure to deliver more glucose to body tissues when levels get too low due to hypothyroidism. At the same time the kidneys function is slower and they can get smaller in size. It was found that plasma renin (produced in kidneys) and angiotensin levels were lowered with hypothyroidism. Water clearance is reduced. Hypothyroidism is a low-renin hypertensive state, which means that levels of sodium in body decrease causing fluid retention. Low thyroid hormonal levels result in the inflammation and plasticity loss of blood vessels. Arterial stiffness is an important determinant of arteriosclerosis, which increases the risk for heart attack and strokes. Thyroid hormones promote the synthesis and action of vasodilators which acts directly on muscles in our arteries. However with low levels, the vessels become less flexible. The synthesis of nitric oxide (a powerful chemical, which dilates blood vessels) from L-arginine is stimulated by T3. Imagine your heart trying to pump blood through blood vessels in the body, which cannot effectively dilate and a resulting stress and damage to the cardiovascular system.
My own experience
The levothyroxine hormonal replacement after my thyroid surgery has raised my T4 levels high over time (in the top of the T4 reference range) while my T3 hormonal levels were low borderline. I suffered from T4 thyrotoxicosis and T3 deficiency. I had developed severe high blood pressure, felt stressed, had needle and pins in my arms and suffered from severe migraines. I went to see a doctor who prescribed a beta blocker -propranolol for my blood pressure problems. I started taking the medication but after few weeks I developed severe muscle spasms, horrible pains in my jaw and terrible muscular pain coupled with some degree of depression. I went to a doctor again and I got prescribed strong antibiotics because he believed my inability to open my mouth and the pain in my jaw and ears indicated some severe throat infection. I came home, while drinking water through a straw and shaking, I had a light bulb moment and realized that propranolol stopped the conversion of T4 (levothyroxine) to T3 (active hormone) in my body. The blood pressure medication had severely depleted my T3 levels which were low to start with. I did not have throat infection or some other terrible illness, I had a severe T3 deficiency. The balance between T4 and T3 is vital. It seemed that in my case, the high T4/low T3 levels caused my high blood pressure. Both, my systolic and diastolic readings were increased but my diastolic blood pressure was significantly raised.
My experience has lead me on a journey of discovery. I had learned that balancing my hormones is important for lowering my blood pressure. I added Natural Desiccated Thyroid (NDT) to my levothyroxine treatment, which ended my blood pressure problems at the time.
Since then, I had invested in blood pressure monitor and check my blood pressure occasionally. It is important to make sure the thyroid hormonal replacement is optimal as any imbalance will eventually show in blood pressure changes. Also, levothyroxine only treatment created a state of oestrogen dominance in my body, which farther decreased T4 into T3 conversion. Natural progesterone cream also helped to get my blood pressure to completely normal levels. More on that in later posts.
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