RESEARCH NEWS Metabolic responses

The objective of this study was to measure the impact of the introduction of daylight saving on when during the day, adults chose to engage in physical activity. The study took place in Western Australia in December 2006.

Just over 1,000 people completed the questionnaires with almost half (45.5%) reporting that daylight saving had affected when during the day they were physically active. During daylight saving fewer people exercised in the morning and more people exercised in the evening.

Cardiorespiratory fitness (CRF) is not only an objective measure of habitual physical activity, but also a useful diagnostic and prognostic health indicator for patients in clinical settings. Although compelling evidence has shown that CRF is a strong and independent predictor of all-cause and cardiovascular disease mortality, the importance of CRF is often overlooked from a clinical perspective compared with other risk factors such as

Whole body vibration (WBV) is a new non-pharmacological approach to counteract osteoporosis. However, the specific vibration protocol to most effectively reduce osteoporotic risk has not been reported. In this study we determined the effect of different WBV devices on bone mineral density (BMD) and neuromuscular performance among 108 postmenopausal women.

The women with an average age of 65.8 were randomly allocated to: (1) rotational vibration training (RVT); 12.5 Hz, 12 mm, 3 sessions/

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The power of policy to influence behaviour change: daylight saving and its effect on physical activity

When analysed at the individual level, 23% of the group quizzed, ceased to exercise in the morning during daylight saving and 22% exercised in the evening only during daylight saving. In addition to changes to the times during the day that people chose to exercise, there was also an overall reduction in the average number of daily exercise sessions, with 8% not exercising at all during daylight saving.

The results suggest that the introduction of daylight saving - a relatively modest compulsory change to increase daylight by one hour - had an impact on patterns of when during the day people were physically active. The results of the study therefore reinforces the value of focusing on policy as an effective means of supporting population behaviour change. Australian and New Zealand Journal of Public Health 2010 Feb;34(1):83-88

Mortality trends in the general population: the importance of cardiorespiratory fitness

hypertension,

diabetes, smoking, or obesity. Several prospective studies

indicate that CRF is at least as important as the traditional risk factors, and is often more strongly associated with mortality. In addition, previous studies report that CRF appears to attenuate the increased risk of death associated with obesity. Most individuals can improve their

CRF through regular physical activity. Several biological mechanisms suggest that CRF improves insulin sensitivity, blood lipid profile, body composition, inflammation, and blood pressure. Based on the evidence, health professionals should encourage their patients to improve CRF through regular physical activity. Journal of Psychopharmacology 2010 Nov;24(4 Suppl):27-35

Effects of whole body vibration training on different devices on bone mineral density

week, for 15 minutes, including dynamic squat exercises; (2) vertically vibration training (VVT); 35 Hz, 1.7 mm; (3) wellness control group (CG): two blocks of 10 low intensity gymnastics sessions. Bone mineral density was measured at the hip and lumbar spine at baseline and after 12 months of training and maximum isometric leg extension strength and leg power were determined using force plates.

A BMD gain at the lumbar spine was observed in both vibration VT groups which was significant

compared to control group value. Neck BMD values tended to increase in both VT groups and remained stable in the control group. Both VT groups gained maximum leg strength compared to CG but whereas power measurements did not reach the level of significance. The authors conclude that WBV training is effective for reducing the risk for osteoporosis by increasing lumbar BMD and leg strength. Medicine and Science in Sports and Exercise 2010 Oct 26. [Epub ahead of print]

of upper-body accel- erometer-controlled video games in adults

Historically, video games have required little physical exertion, but new systems now utilise handheld accelerometers that require upper-body movement. It is not fully understood if the metabolic workload while playing these games is sufficient to replace routine physical activity. The purpose of this study was to quantify metabolic workloads and estimate calorie expenditure while playing upper-body accelerometer-controlled and classic seated video games. Nineteen adults completed a peak oxygen consumption treadmill test followed by an experimental session where exercising metabolism and ventilation were measured while playing three video games: control (CON), low activity (LOW) and high activity (HI).

Resting metabolic measures (REST) were also acquired. Estimated calorie expenditure during the HI was significantly related to aerobic fitness, but not during other conditions. An active video game significantly elevated oxygen consumption and heart rate, but the increase was dependent on the type of game. The mean oxygen consumption reserve during the HI video game was below recommended international standards for moderate and vigorous activity. Although upper-body accelerometer- controlled video games provided a greater exercising stimulus than classic seated video games, these data suggest they should not replace routine moderate or vigorous exercise. Editor’s note: Does the newly- launched Xbox Kinect have the power to change this outcome? Applied Physiology, Nutrition and Metabolism 2010;Oct 35(5):643-649

The REPS Journal 2010;19(Dec):11-12