Scientists show that light therapy may increase blood pressure in hypertension

August 7, 2018, RUDN University
Experimental study of the effects of bright light with the use of telemetric monitoring technology carried out at V.A. Frolov Department of General Pathology and Pathological Physiology, Institute of Medicine, RUDN University. Credit: Mikhail Blagonravov.

A team from the Institute of Medicine, RUDN University discovered that light therapy (treating mental disorders with bright light) increased blood pressure in animals with inherited hypertension. It will help to make light therapy safer for patients with essential hypertension. The report was presented at the Annual Meeting of the Society for Light Treatment and Biological Rhythms in Groningen, the Netherlands on June 21-24, 2018. The conference abstracts were published in the Journal Neuropsychobiology.

Light therapy (phototherapy) is used to treat sleep disorders, depression and seasonal . In order to study its effects on the cardiovascular system (especially in case of stable increase in ) and to make phototherapy safer for patients suffering from hypertension, experts from RUDN University conducted experiments on rats for five months.

The experiments involved healthy animals and spontaneously hypertensive rats. In the animals of both groups, blood pressure and heart rate were monitored during daytime and nighttime periods. For this purpose, miniature devices monitoring blood pressure, ECG and motion activity continuously for 24 hours were implanted into the animal bodies. The animals lived in cages with a stable light pattern consisting of 12 hours of complete darkness followed by 12 hours of light at the level of about 300 lux (similar to average office lighting). Then the scientists carried out a session of phototherapy increasing the light intensity level to 10,000 lux (similar to sunlight in dappled shade, for example, under a tree). Blood pressure and were registered for 24 hours on the day before the session (as a control measurement) and on the day of bright light exposure.

The results of the experiment showed that under the action of bright light blood pressure in rats with inherited hypertension increased by 10 mm Hg on the average. The changes were characteristic of both systolic and , i.e. the values during heart muscle contraction and relaxation, correspondingly (they are usually specified in the results of measurements, e.g. 120/80 mm Hg). The effect remained notable for several hours, even when the lighting returned to the regular levels. No deviations from the average values of blood pressure were registered in healthy animals with . Heart rate did not change in either of the groups.

"We can be sure now: When phototherapy is prescribed, concomitant conditions should also be taken into consideration, including hypertension of different origin. We may suggest that in these cases the intensity of light should be milder. This can be achieved either by reducing the time of exposure or the brightness of ," said Mikhail Blagonravov, MD, head of V.A. Frolov Department of General Pathology and Pathological Physiology, the Institute of Medicine, RUDN University.

Explore further: First look at the new 2018 European guidelines for the treatment of high blood pressure

More information: Chronobiology: Society for Light Treatment and Biological Rhythms, 30th Annual Meeting, Groningen (The Netherlands), June 21–24, 2018, Neuropsychobiology (2018). DOI: 10.1159/000489584

Related Stories

First look at the new 2018 European guidelines for the treatment of high blood pressure

June 9, 2018
A first look at the new European Guidelines for the treatment of high blood pressure was presented at the European Society of Hypertension meeting in Barcelona on June 9th 2018. These long-awaited guidelines have been jointly ...

Why do we develop high blood pressure?

March 9, 2017
Abnormally high blood pressure, or hypertension, may be related to changes in brain activity and blood flow early in life. That's according to a study conducted on a rat model of high blood pressure, published in Experimental ...

Severe pre-eclampsia often leads to undetected high blood pressure after pregnancy

February 5, 2018
Lingering hypertension is common and may go unnoticed among women who have severe pre-eclampsia during pregnancy, according to new research in the American Heart Association's journal Hypertension.

Researchers find unhealthy gut microbes a cause of hypertension

February 3, 2017
Researchers have found that the microorganisms residing in the intestines (microbiota) play a role in the development of high blood pressure in rats. The study is published in Physiological Genomics. It was chosen as an APSselect ...

Low sodium-DASH diet combination dramatically lowers blood pressure in hypertensive adults

November 13, 2017
A combination of reduced sodium intake and the DASH diet lowers blood pressure in adults with hypertension, according to preliminary research presented at the American Heart Association's Scientific Sessions 2017, a premier ...

Blood pressure control best achieved with a multilevel, multicomponent approach

December 25, 2017
Current clinical guidelines recommend lower blood pressure targets for the general population, yet control remains elusive for most. A new study suggests that patients with hypertension can best achieve blood pressure control ...

Recommended for you

No sweat required: Team finds hypertension treatment that mimics effect of exercise

October 16, 2018
Couch potatoes rejoice—there might be a way to get the blood pressure lowering benefits of exercise in pill form.

New model suggests cuffless, non-invasive blood pressure monitoring possible using pulse waves

October 16, 2018
A large team of researchers from several institutions in China and the U.S. has developed a model that suggests it should be possible to create a cuffless, non-invasive blood pressure monitor based on measuring pulse waves. ...

Why heart contractions are weaker in those with hypertrophic cardiomyopathy

October 16, 2018
When a young athlete suddenly dies of a heart attack, chances are high that they suffer from familial hypertrophic cardiomyopathy (HCM). Itis the most common genetic heart disease in the US and affects an estimated 1 in 500 ...

Novel genetic study sheds new light on risk of heart attack

October 12, 2018
Loss of a protein that regulates mitochondrial function can greatly increase the risk of myocardial infarction (heart attack), Vanderbilt scientists reported Oct. 3 in the journal eLife.

Researchers say ritual for orthodox Jewish men may offer heart benefits

October 11, 2018
A pilot study led by researchers at the University of Cincinnati (UC) College of Medicine suggests Jewish men who practice wearing tefillin, which involves the tight wrapping of an arm with leather banding as part of daily ...

Markers of dairy fat consumption linked to lower risk of type two diabetes

October 10, 2018
Higher levels of biomarkers of dairy fat consumption are associated with a lower risk of developing type 2 diabetes, according to new research published today in PLOS Medicine. The study, in more than 60,000 adults, was undertaken ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.