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Bite-sized bouts of exercise: Why they are valuable and what they are missing


 

Short bursts of activity are approximately as effective for general health as longer sessions, especially for those who are mainly sedentary, according to several recently published studies.

If your fitness goals are greater, and you want to build muscle strength and endurance, compete in a 5K, or just look better in your swimsuit, you will need to do more. But for basic health, it appears that short bursts can help, the new research papers and experts suggest.

“Whether you accumulate activity in many short bouts versus one extended bout, the general health benefits tend to be similar,” Amanda Paluch, PhD, a physical activity epidemiologist at the University of Massachusetts, Amherst, said in an interview.

Current public health recommendations from the Centers for Disease Control and Prevention suggest doing at least 150 minutes of moderate intensity physical activity per week for health benefits, but this activity can be accumulated in any way over the week, she noted. Previous versions of the CDC guidelines on exercise suggested that physical activity bouts should be at least 10 minutes each, but the latest version of the guidelines acknowledges that bursts of less than 10 minutes may be beneficial.

However, “the activity or fitness level at which someone starts and the specific health goals matter,” Dr. Paluch continued. “Short bouts may be particularly beneficial for those least active to get moving more to improve their general wellness.”

The current federal physical activity guidelines are still worth striving for, and patients can work their way to this goal, accumulating 150 or more minutes in a way that works best for them, she added.

“There is a lack of research directly comparing individuals who consistently accumulate their activity in many short bouts versus single bouts over an extended period of time,” Dr. Paluch noted. From a public health perspective, since both short and long bouts have health benefits, the best physical activity is what fits into your life and helps build a lifelong habit.

The benefits of exercise for cardiovascular health are well documented. A review from Circulation published in 2003 summarized the benefits of regular physical activity on measures of cardiovascular health including reduction in body weight, blood pressure, and bad cholesterol, while increasing insulin sensitivity, good cholesterol, and muscular strength and function. In that review, author Jonathan N. Myers, PhD, now of Stanford (Calif.) University, noted that “one need not be a marathon runner or an elite athlete to derive significant benefits from physical activity.” In fact, “the greatest gains in terms of mortality are achieved when an individual goes from being sedentary to becoming moderately active.”

A recent large, population-based study showed the value of short bursts of exercise for those previously sedentary. In this study, published in Nature Medicine, a team in Australia used wearable fitness trackers to measure the health benefits of what researchers have named “vigorous intermittent lifestyle physical activity” or VILPA.

Some examples of VILPA include power walking on the way to work, climbing stairs, or even running around with your kids on the playground.

Specifically, individuals who engaged in the median VILPA frequency of three bursts of vigorous activity lasting 1-2 minutes showed a 38%-40% reduction in all-cause mortality risk and cancer mortality risk, and a 48%-49% reduction in cardiovascular mortality risk.

The researchers repeated their analysis for a group of 62,344 adults from the UK Biobank who reported regular vigorous physical activity (VPA). They found similar effects on mortality, based on 1,552 deaths reported.

These results suggest that VILPA may be a reasonable physical activity target, especially for people not able or willing to exercise more formally or intensely, the researchers noted.

“We have known for a long time that leisure-time exercise often reaches vigorous intensity and has many health benefits, but we understand less about the health potential of daily movement, especially activities done as part of daily living that reach vigorous intensity,” lead author Emmanuel Stamatakis, PhD, professor of physical activity, lifestyle and population health at the University of Sydney’s Charles Perkins Centre, said in an interview.

“As long as the heart rate goes up for a minute or 2 it will likely be vigorous activity,” Dr. Stamatakis said in an interview. “It is also important that clinicians effectively communicate how patients can know that they are reaching vigorous intensity,” he said.

Signs of vigorous intensity include increased heart rate and getting out of breath after about 20-40 seconds from the start of the VILPA burst. After about a minute of VILPA, the person doing it should be too out of breath to speak more than a few words comfortably, he said.

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