Dark Chocolate Lowers Blood Pressure

For people with hypertension, eating dark chocolate can significantly reduce blood pressure. Researchers writing in the open access journal BMC Medicine combined the results of 15 studies into the effects of flavanols, the compounds in chocolate which cause dilation of blood vessels, on blood pressure.

Researchers from the University of Adelaide, Australia, to conduct the analysis. She said, “Flavanols have been shown to increase the formation of endothelial nitric oxide, which promotes vasodilation and consequently may lower blood pressure. There have, however, been conflicting results as to the real-life effects of eating chocolate. We’ve found that consumption can significantly, albeit modestly, reduce blood pressure for people with high blood pressure but not for people with normal blood pressure.”

The pressure reduction seen in the combined results for people with hypertension, 5mm Hg systolic, may be clinically relevant — it is comparable to the known effects of 30 daily minutes of physical activity (4-9mm Hg) and could theoretically reduce the risk of a cardiovascular event by about 20% over five years.

The researchers are cautious, however, “The practicability of chocolate or cocoa drinks as long-term treatment is questionable,” said Dr Ried.

Strength training protects against high blood pressure

If you have high blood pressure, many doctors and patients think you shouldn’t be doing strength training. This is not the case write researchers at the Catholic University of Brasilia in a new research. The researchers say strength training actually has a positive effect on people with high blood pressure.

Exercise can help prevent high blood pressure, and people who already have high blood pressure can reduce it a little by starting to do more exercise. The indications that endurance exercise – for example, 40 minutes of cycling at an intensity of 60 percent VO2max – helps reduce blood pressure are strong.

Less is known about the effects of strength training on blood pressure, although we do know that, during sets with heavy weights, blood pressure can shoot up. For people with vulnerable blood vessels, the temporary peak in blood pressure may be too much, although there are studies that suggest that good breathing technique and the use of blood-pressure lowering medicines such as propranolol can help flatten off the peak.

We also know that blood pressure declines a little in the first hour after a strength-training session, in people with normal blood pressure and in those with raised blood pressure. This would suggest that strength training might have a positive effect on blood pressure.

The researchers wanted to know what the effect of strength training would be on women with high blood pressure who were taking medication for this. Would strength training have a positive effect? Or would the women be better off doing moderately intensive forms of exercise?

To answer this question the researchers got 32 women aged between 60 and 75, all of whom had high blood pressure, to do strength training three times a week for four months [EG].

The women trained the main muscle groups each session, doing ten simple basic exercises: lat-pulldowns, leg-extensions, chest presses, hip abductions, leg curls, leg presses and calf raises. The women performed three sets of each exercise. They started off at 60 % of the weight with which they could just manage 1 rep, and built this up gradually to 80 %.

When the women were not taking medication against high blood pressure, their systolic pressure [pressure during the heart beat] was above 140 mmHg and their diastolic pressure [the pressure between two heart beats] was above 90 mmHg.

The first table below shows that the resting systolic blood pressure in the experimental group decreased by 14.3 mmHg. This was a statistically significant effect.

The second table shows that the diastolic resting blood pressure went down by 3.6 mmHg. The effect was not quite significant.

So women with high blood pressure that is under control can happily do strength training the researchers conclude. They must be sure to gradually increase the weight they work with.

Careful strength training can even help to keep blood pressure under control and may even help lower it. “Chronic reduction of resting blood pressure observed in this study may be translated as a significant protective effect on the volunteers cardiovascular system”, the Brazilians write.