By ANN LUKITS
New Year's resolutions to reduce body weight and increase exercise could be achieved in increments of activity lasting less than 10 minutes, a study in Medicine & Science in Sports & Exercise suggests. Current U.S. guidelines recommend Americans get 150 minutes of physical activity a week, with the activity accumulated in bouts of at least 10 minutes.
From 2008 to 2010, Boston researchers assessed the physical activity of 2,109 men and women enrolled in a larger, long-running study of cardiovascular risk factors. Subjects were 47 years old on average and more than half were overweight. Activity levels were analyzed by wearing accelerometers for eight days.
On average, participants engaged in half an hour of moderate- and vigorous-intensity exercise a day, of which approximately 19 minutes involved short bouts of activity less than 10 minutes, the data showed. Walking briskly, heavy cleaning, badminton and golf were considered moderate activities. Vigorous exercises included hiking, jogging, farming, shoveling and competitive sports such as tennis and soccer.
Of the subjects, 10% of men and 15% of women met the U.S. guidelines of performing at least 150 minutes of exercise weekly in bouts of 10 minutes or more. When all physical activity, both greater or less than 10 minutes in length, was considered, 56% of men and 47% of women were compliant with the guidelines, researchers said. Women tended to engage in more moderate-to-vigorous exercise bouts of 10 minutes or more while men exercised in shorter bouts.
Compared with noncompliant subjects, all those who met the U.S. weekly exercise guidelines, regardless of how the 150 minutes were accrued, had significantly lower triglycerides, waist circumferences and body mass indexes, and improved cholesterol scores, tests showed. Exercising had a stronger impact on cardiovascular risk factors in women than men, possibly because of physiological differences or unmeasured factors, researchers said.
Given the high rates of sedentary behavior in the U.S., the findings may encourage inactive individuals to become more active, they said.
Caveat: The study was based on data primarily from white subjects. Accelerometers are unable to capture certain activities in which the participant is stationary or has limited hip movement, such as strength training or
cycling, researchers said. One researcher owns KineSoft, the software used in the accelerometer data
Trauma and growth: A new study of California births found that boys born three months after the terrorist attacks of Sept. 11, 2001, had significantly greater cognitive development at age 2 than children born before the attacks. Previous research has shown that miscarriage rates, especially involving male fetuses, increased in the wake of the terrorist attacks.
Researchers suggest the stress of 9/11 on pregnant women may have triggered a biological mechanism that led to spontaneous termination of frail male fetuses, resulting in relatively improved development of the hardier males who survived.
In the latest study, reported in Social Science & Medicine, a California-Wisconsin research team used data from a national study of U.S. births in 2001 to compare the development of California boys born in December with three control groups. The groups included boys born in California before 9/11; girls born in California in December; and boys and girls born outside California.
Height and cognitive development were assessed at 9 months in 600 boys and 500 girls born in California and 8,650 children born in other states. A second assessment, at 24 months, included 500 boys and 400 girls born in California and 7,600 children born outside the state.
No significant height differences were found between the California boys born in December and controls, results showed. Cognitive scores at 9 months also didn't differ significantly. But at 24 months, the December-born California boys had unexpectedly high cognitive scores compared with controls. The difference was equivalent to the average variation in cognitive scores between children born at a normal gestational weight and those weighing less than 3.5 pounds, the researchers said.
The findings support previous research indicating national calamities impact boys more than girls before birth, researchers said. Previous studies reported that California recorded a 2% decrease in male births in December 2001 but the rate of female births didn't change.
Caveat: The analysis didn't include data on boys born in New York City in January 2002, which reported a 5% drop in male births after Sept. 11 but no change in female births.
Dental anxiety: Applying acupuncture needles to the outer ear significantly reduced anxiety in dental patients waiting for checkups, gum treatments, tooth-pain consultations and other routine procedures compared with other acupuncture sites or no treatment, says a report in Clinical Oral Investigations. Research has shown that 40% to 60% of patients visiting the dentist suffer from fear and anxiety, which can prevent them from seeking treatment and result in more decayed and missing teeth, researchers said.
The study involved 182 Austrians in their mid-30s who were scheduled for various dental procedures from 2007 to 2008. A group of 61 patients got 20 minutes of acupuncture on three sites on the outer ear, called auricular acupuncture, before their dental treatments. Another group of 60 patients had acupuncture needles applied to the finger, shoulder and tonsils for 20 minutes. A control group of 60 patients weren't treated.
Patients rated their fear from 0 (none) to 10 (maximum) while in the waiting area and again in the dental chair before treatment. Their "state anxiety," or anxiety in specific situations, was also scored from 20 to 80. A score of 50 or greater was considered very high anxiety.
Average state anxiety scores decreased significantly in both groups receiving acupuncture—from 54.7 to 46.9 in the auricular group and from 51.9 to 48.4 in the non-auricular group. But state anxiety rose from 51 to 54 in the group that received no acupuncture. Side effects were reported by 20% of subjects in both acupuncture groups and included a strange feeling at the treated ear, or dizziness.
Non-auricular acupuncture may have produced a placebo effect that was better than having no treatment, researchers said.
Caveat: The additional attention given to acupuncture patients while the needles were applied may have distracted them from the coming dental treatment and helped to reduce anxiety, researchers said.
Surgical infections: Patients treated for skin infections up to a year or more before undergoing major surgery are at greater risk of developing serious postoperative infections or dying than other patients, suggests a study in Annals of Surgery. The variation might be due to innate immune differences in those people who had previous infections, suggesting that not all post-surgical infections can be prevented, the study said. An estimated 500,000 surgical infections are reported in the U.S. annually, despite aggressive infection-control measures by hospitals.
The subjects were 613 men and women in their early 60s, with normal immune function, who underwent procedures considered high risk for infection at two Baltimore hospitals from 2007 to 2010. The procedures included cardiac and vascular surgeries, spinal fusion and craniotomy. One or more previous skin infections requiring antibiotics were reported by 22% of the subjects and 18% tested positive for Staphylococcus aureus, a major cause of hospital-acquired infections.
About 4% of the patients developed a surgical-site infection or died within six months, results showed. The rate of infection or death due to infection was 6.7% in patients with a previous skin infection and 3.1% in those without an earlier skin infection. Risk of infection was almost three times as great in those who tested positive for S. aureus and more than double in unmarried men, the study found. Marital status is unlikely to be a direct cause of infection but it may be an indicator of an individual's underlying health status, researchers said.
Intrinsic differences in susceptibility to infection may predispose some patients to spontaneous and repeated bacterial infections, they said.
Caveat: The molecular link between a history of skin infection and postoperative infections wasn't identified. Skin infections were self-reported, raising the possibility of error. The findings may be limited to patients who undergo high-risk surgical procedures, researchers said.
Gravity and bones: Astronauts on space missions and patients confined to long periods of bed rest are both at risk of rapid bone loss due to lack of weight-bearing activity but it isn't known why some individuals lose more bone than others. A study in the American Journal of Physiology - Endocrinology and Metabolism suggests that genetic factors may play an important role in how bones adapt to inactivity.
Experiments in San Francisco used a technique called skeletal unloading on two common but genetically different strains of mice. Skeletal unloading simulates a weightless environment by elevating the rodents' back legs to eliminate weight bearing in the hindquarters. Mice from both genetic strains were suspended in a head-down tilt for periods of one, two and four weeks, while control mice weren't restrained.
After one week, both strains had half as many cells called osteoprogenitors, which grow and repair bones, than control mice. This decrease was accompanied by a 30% to 50% decline in bone-forming cells called osteoblasts in one strain that remained suppressed at four weeks, whereas there was no change in osteoblasts in the other strain.
Unloading also triggered significant increases in osteoclasts, cells that destroy bone, at dramatically different rates in the two strains. The volume of bone declined progressively in both strains but the body weights of unloaded mice weren't significantly different from control mice, suggesting the bone changes weren't due to weight loss or altered food intake, researchers said.
The mechanisms underlying bone loss appeared to be different between the strains and possibly determined by genetics, they said. In humans, loss of physical activity of any kind, even a sedentary, "couch potato" lifestyle, also decreases bone at varying rates, they said.
Caveat: The research was tested on mice using a simulated weightless environment.
Back Pain: Not Just for Adults
Sitting on a hard foam wedge on chairs during the school day reduced back pain in teens by 58% compared with those not using the wedge, says a report in the journal Physiotherapy. Back pain is as common in adolescents as adults and caused by many of the same factors, such as prolonged sitting in poorly designed seating.
Twelve schools in Suffolk, England, took part in the four-week study in 2005, which included 97 students, 14 to 16 years old, with back pain. Of the students, 51 used a wedge for three weeks in all classes except the science lab, which had stools. A control group of 46 students didn't use the wedge. Most complained of pain in the lower back region. Back pain was scored from 0 (none) to 10 (worst) and reported in diaries on the morning and evening of school days, starting one week before the wedges were used.
Both groups had similar back-pain levels at the start of the first week but wedge users reported incremental improvements in pain over each half day. Pain was significantly worse in the evening than in the morning in both groups, though the evening increase was significantly smaller in wedge users. The wedges increased the forward tilt of the pelvis, which reduced pressure on the lower lumbar discs and the muscular effort required to maintain good posture, researchers said.
Caveat: Some students found the wedge too cumbersome to carry through the school day and three said it was uncomfortable. The study didn't track back pain after the study ended as many students left school permanently at the end of the term, researchers said.
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A version of this article appeared January 8, 2013, on page D3 in the U.S. edition of The Wall Street Journal, with the headline: Exercise in Short Bursts Is Effective.