Interval training is a popular way to structure workouts. By alternating periods of high-intensity exercise with low intensity or recovery intervals, you get the benefits of a cardiovascular workout in a shorter period of time. Plus, studies show that vigorous exercise offers more cardiovascular benefits than working out at a low to moderate intensity for longer periods of time.
You can benefit from some form of interval training regardless of your fitness level. In fact, a study published in The American Journal of Cardiology showed that even people with cardiovascular disease can safely improve the health of their heart through supervised interval training. Of course, you should always consult your doctor first if you have heart disease. Even cardiologists are now recommending supervised interval training to people with stable heart disease.
Blood Vessel Function & the Endothelium
What you may not realize is that another organ plays an essential role in keeping you healthy as you age. It’s the cells that line the inside of your blood vessels collectively called the endothelium. Yes, scientists and doctors consider the endothelium or endothelial system, as it’s sometimes called, to be an organ since it has functions that impact your health. In fact, endothelial dysfunction, where endothelial cells don’t function properly, is a contributor to heart disease, high blood pressure, and type 2 diabetes.
What might surprise you is how thin this layer of endothelial tissue is – only a single cell thick. Yet these cells play important roles in health. This abundant group of cells helps to regulate blood pressure, blood clotting, and even immune function by causing blood vessels to open wider (vasodilation) or constrict. Most importantly, endothelial dysfunction plays a key role in the development of atherosclerotic heart disease.
A gas produced by the endothelial cells that line your blood vessels is nitric oxide. As endothelial dysfunction develops, cells lining the endothelium produce less nitric oxide gas. This is a hallmark of endothelial dysfunction and a sign that all is not well with the inside of your blood vessels. As nitric oxide production inside the vessel drops, it’s harder for arteries to dilate during periods when you need more blood flow, like during exercise.
Nitric oxide plays a key role in regulating blood vessel width. When blood flow increases the force on the vessels, this signals the endothelial cells to produce more nitric oxide so the blood vessel will dilate. When you have endothelial dysfunction, the cells can’t do this as well. Plus, with less nitric oxide available, the lining of the vessel can become inflamed. We now know that inflammation damages blood vessels and contributes to abnormal blood clotting. This, in turn, leads to heart attacks and strokes.
What causes endothelial dysfunction to develop? Anything that damages the thin, delicate cells that line the blood vessels and produce nitric oxide can do it. A major factor is smoking. One study showed that particles in smoke, other than nicotine, directly damage the delicate endothelial cells. High blood pressure, elevated lipids, and high blood sugar are other elements that damage the thin layer of endothelium.
Research shows that oxidative stress can damage these cells as well. Unfortunately, aging, too, takes its toll on your endothelium. That’s one reason heart disease and stroke become more common with age. Finally, being obese is a risk factor for poor blood vessel function. It’s not clear how obesity interferes with healthy endothelial function. One theory is that fat cells release inflammatory chemicals that damage the blood vessel lining and the cells that produce nitric oxide.
Now you know why a healthy endothelial function is so vital for good health!
Interval Training and Endothelial Function
If you’re concerned about your own endothelial function, there’s good news. A new study shows interval training improves endothelial function in older adults, including those with type 2 diabetes. That’s important since endothelial function worsens with age.
In a recent study, researchers divided middle-aged and older participants into groups based on their health status. One group consisted of healthy exercisers without diabetes, a second was made up of non-exercisers without diabetes, while a third was composed of people who exercised regularly and didn’t have diabetes. All three groups took part in similar interval-based workouts. The workout was structured with one-minute intervals of activity and one-minute rest intervals. There was a 3-minute warm-up and cooldown. The active intervals consisted of either aerobic and resistance exercises.
In the study, the researchers used a non-invasive technique called flow-mediated dilation to measure blood flow. The results? All of the participants experienced improvements in endothelial function in response to interval resistance training. When the participants did aerobic intervals instead, endothelial function improved for those in the first and third group but not for the second group of non-exercisers.
The conclusion? Interval resistance training appears to be a blood vessel friendly activity. This is an important finding since most research has focused on aerobic exercise as a way to improve endothelial function. Keep in mind that some studies show little or no improvements in endothelial function with resistance training. However, these studies may have been too short-term to show benefits. It appears that interval resistance training may offer similar blood vessel benefits to aerobic exercise. We already know that aerobic exercise, along with improving heart health, enhances blood vessel function. Resistance exercise may offer similar health perks.
The Bottom Line
Interval training, using resistance exercises, is a time-expedient way to work out. You can build strength or muscle endurance, burn fat, and even improve how your blood vessels function, based on this study. If you’re not taking advantage of this challenging and effective way of working out, why not?
References:
Science Daily. “Interval Exercise Training Improves Blood Vessel Function in Older Adults” September 27, 2016.
Clin Chem. 1998 Aug;44(8 Pt 2):1809-19.
Diabetes Research and Clinical Practice. Volume 79, Issue 3, March 2008, Pages 405–411
Journal of Cardiology. November 2010Volume 56, Issue 3, Pages 307–313.
BMC Cardiovascular Disorders20066:3 DOI: 10.1186/1471-2261-6-3.
Vasc Health Risk Manag. 2005 Sep; 1(3): 183–198. Published online 2005 Sep.
Diabetes Metab J. 2011 Aug; 35(4): 364–373.
J Am Coll Cardiol. 1999;33(5):1379-1385. doi:10.1016/S0735-1097(99)00036-4.
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