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In the news: Exercise to Keep Blood Pressure in Check; Vitamin D May Help Protect Colon Health

Isometric Exercises May Lower Blood Pressure

Regular exercise is one of the pillars of preventing and treating hypertension, along with weight reduction, eating the DASH diet, reducing sodium, and lowering stress. Current recommendations call for at least a half an hour of aerobic exercise most days of the week.

While many forms of exercise can be beneficial for high blood pressure, is there a particular mode of exercise that might be optimal for reducing high blood pressure? Since hypertension affects nearly half of Americans and can lead to serious health problems (heart attack, stroke), research into exercise modes continues.

In the current study(1), UK researchers analyzed data from 270 randomized controlled trials that included more than 15,800 people assigned to different types of exercise. The trials included aerobic exercise training (AET), resistance training (RT), combined training (CT), high-intensity interval training (HIIT) and isometric exercise training (IET).

While the researchers found that all modes of exercises were effective at reducing both systolic and diastolic blood pressure, the isometric (IET) was the best – and by a considerable amount for systolic blood pressure.

IET showed reductions (in mm Hg) of 8.24/4 for resting systolic pressure compared with 4.49/2.253 for aerobic, 4.55/3.04 for resistance, 6.04/2.54 for combined, and 4.08/2.50 for high-intensity interval training.

All the types of exercise studied significantly reduced systolic pressure in normal blood pressure groups, while reductions were larger in those with hypertension.

If you have high blood pressure, it’s always a good idea to check with your own physician to decide the form of exercise that’s best for you.

Isometric exercise involves increasing tension in a muscle without moving any surrounding joints. Wall squats, for example, involve slowly moving into a squat as the back is pushed against a wall, the position held, then coming back up. Examples of other isometric exercises include planks, calf raises and glute bridges.

Can Maintaining Adequate Vitamin D Blood Levels Lower Colorectal Cancer Risk?

The past several decades has seen a drop in the death rate from colorectal cancer among older Americans, most likely due to better detection (regular colonoscopies) and lower rates of smoking. However, the rate of this cancer has been increasing among those younger than 50.

Why this rate is rising isn’t understood, but many factors have been linked with higher risk of colorectal cancer including lack of exercise, being overweight, eating a low-fiber, high-fat diet, consuming processed meats, and other factors.

Results from a new study(2) suggest that vitamin D may be a contributing factor in colorectal cancer prevention, possibly through its ability to help regulate gene expression.

Researchers followed a little over 236,000 people for whom they had blood levels of vitamin D, for about 6 ½ years. They compared blood levels of those who developed colorectal cancer with those who did not.

The risk of colorectal cancer was higher among younger individuals 50 and under who had lower blood level of vitamin D (less than 20 ng/mL).

Those with vitamin D levels above 20 ng/mL had a reduced risk of developing this cancer, and the risk continued to drop with greater vitamin D blood levels. For people older than 50, the association of vitamin D and risk for of developing colorectal cancer were like those seen in younger participants, but not as pronounced.

The results do not prove that vitamin D may help prevent this cancer, but they do set the stage for further studies.

References

1. Edwards J, et al. Exercise training and resting blood pressure: a large-scale pairwise and network meta-analysis of randomized controlled trials. Br J Sports Med, Epub July, 2023.
2. Kim Y, et al. Serum 25-hydroxyvitamin D levels and risk of colorectal cancer: an age-stratified analysis, Gastro-enterol. 165: 920-931, 2023.