The sleeping side at night – blood pressure, blood flow and well-being
“Those on the right spare their hearts” was the title of Welt am Sonntag on 1 July 2018 – but it’s not that simple! This is because the load on the cardiovascular system caused by a particular lateral position varies from person to person.
You will find a lot on the Internet about the topic “Circulation and Sleep”, much of it is nonsense. You will also find few scientific data on these interrelationships. In cardiopractice, we have many years of quantified metrological experience with circulatory changes in different body positions thanks to the FinapresⓇ system. This also has consequences for the treatment of various diseases. Here we have made good experiences with sleep disorders, both with increased and lowered blood pressure as well as with heart weakness and heart valve defects.
Sleep side – individual involuntary or arbitrary?
Almost all people have a preferred sleeping side, many sleep on the right side of the body, quite a few on the left side and some even like to sleep on their stomachs. The reason why you choose a certain sleeping side is usually instinctive, i.e. you feel most comfortable and calm inside on this side, we call it the involuntary sleeping side. If you have other reasons for the choice of a side, e.g. you like to lie towards the window or away from your partner, then we call it the arbitrary sleeping side.
Sleep side – blood pressure, blood flow and Vascular resistance different
Your blood pressure can also vary, for example, between the right and left side position up to 40 mmHg. These findings on blood pressure are known from polysomonographic measurements taken in sleep medicine.
What is not known is the influence of the lateral position when lying on differentiated circulation parameters. In fact, circulatory values such as blood pressure, blood flow and vascular resistance are also different in alternating lateral positions. In cardiopractice we have extensive experience in this area thanks to the possibility of differentiated circulation measurement with the FinapresⓇ system.
Our observation always begins with the determination of the diameter of the lower vena cava, which returns oxygen-poor blood to the body. As a rule, the blood flow on the side of the body on which the lower vena cava is placed is higher and the arterial blood pressure or the calculated vascular resistance is lower. The cardiovascular system is thus in principle more relieved. Here we assume a protective reflex that protects the anatomical structures, e.g. the thin musculature of the antechambers, from overstretching: wide veins mean increased wall tension in the anterior ventricle and have a relieving arterial dilatation.
In principle, this correlation represents the normal state, with the vascular resistance always lower on one side than on the other. The best relieved side is often instinctively chosen as the involuntary sleeping side. In about 30 % of the cases, the cycle is better relieved in left-handed position than in right-handed position.
Circulation differentiated measurement when lying down
Are you suffering from sleep disorders or If you experience changes in your circulation, such as too low or too high blood pressure, a heart failure or a heart valve defect, we will carry out a so-called rotation measurement while you are lying down.
We begin by determining the diameter of the lower vena cava directly before the transition to the right anterior chamber of the heart in different lateral positions while lying down. Then the measurements in the arterial vascular circuit follow. With the FinapresⓇ system, we derive the differentiated circulatory parameters such as blood flow, vascular resistance and, as a measure of neurovegetative balance, baro receptor sensitivity in different lateral positions.
The duration of the examination is about 10 minutes, the evaluation takes about 5 minutes.
We use our findings on changes in the circulation again and again in the case of health disorders.
Sleep side in the night – sleep disturbances
If you suffer from sleep disorders, above all from sleep disorders and lie arbitrarily on the cardiac side, then we can give you the practical advice to change the sleeping side. This sometimes results in your partner changing the side of the bed (in order to lie further towards or away from you) or sometimes changing the bed (in order to lie further towards the window or door).
sleeping side at night – high blood pressure
If your blood pressure is elevated, we usually advise you to sleep on the low pressure side. This not only relieves the load on your heart, but can also help to improve your overall blood pressure. This is because in the case of pathological high blood pressure, the target value in the control loop of the blood pressure is adjusted upwards. Through consistent sleeping on the Low pressure side, the setpoint can be normalized downwards.
sleep side at night – drowsiness, dizziness, fainting
Young people in particular often experience a combination of low blood pressure and drowsiness, including fainting spells. Younger people usually sleep more deeply and in combination with sleep on the low pressure side, this can cause problems. It is precisely this combination that results in the blood pressure set point being set too low at night. This leads to the known problems during the day, when the blood supply to the brain has to be correct while standing. We are then usually in a position to provide help with a recommendation for the sleeping position, if necessary also with supporting mechanical measures (guide resistance during sleep).
Sleep side at night – cardiac insufficiency and valvular insufficiency
Of course, this approach is also important for people with cardiac insufficiency or cardiac valve defects in order to relieve the burden on the heart during sleep. If the heart only has to pump against a low-normal arterial resistance instead of a high vascular resistance during sleep, then it is better relieved and can recover better.
In aortic valve stenosis, the most common heart valve defect, the left heart muscle must be pumped through the narrowed valve alone against increased resistance. At night, therefore, it is precisely here that additional stress caused by sleep on the high-pressure side should be avoided.
Just when the Aortic valve insufficiency and/or mitral valve insufficiency, if a valve is leaking, the downstream vascular resistance should be low so that as little blood as possible flows back into the left main or anterior chamber in the event of a leaking valve. This not only relieves the heart during sleep, but also the lungs.
Recommendation for the correct sleeping position – individually only with differentiating measurements
We have described the normal circulatory behaviour with different lateral positions in the previous versions. However, there are some exceptions to this normal state. We see this again and again in people with low blood pressure and drowsiness, high blood pressure, heart failure. The use of cardiovascular drugs also changes the circulatory behaviour when lying down.
We therefore advise against measuring blood pressure alone as a measure of relief for the cardiovascular system. This procedure can result in incorrect diagnoses and incorrect treatment. A complete circulation measurement is always the prerequisite for correct action, especially when changes occur while lying down.
Ⓒ Cardiopraxis – Cardiologists in Düsseldorf & Meerbusch