Changes in leisure time physical activity and risk of all-cause mortality in men and women: the Baltimore Longitudinal Study of Aging

Assessment of wear/nonwear time classification algorithms for triaxial accelerometer

PURPOSE

The objective of this study is to assess the performance of existing wear/nonwear time classification algorithms for accelerometry data collected in the free-living environment using a wrist-worn triaxial accelerometer and a waist-worn uniaxial accelerometer in older adults.

METHODS

Twenty-nine adults age 76 to 96 yr wore wrist accelerometers for approximately 24 h per day and waist accelerometers during waking for approximately 7 d of free living. Wear and nonwear times were classified by existing algorithms (Alg([ActiLife]), Alg([Troiano]), and Alg([Choi])) and compared with wear and nonwear times identified by data plots and diary records. With the use of bias and probability of correct classification, the performance of the algorithms, two time windows (60 and 90 min), and vector magnitude (VM) versus vertical axis (V) counts from a triaxial accelerometer were compared.

RESULTS

Automated algorithms (Alg([Choi]) and Alg([Troiano])) classified wear/nonwear time intervals more accurately from VM than V counts. The use of the 90-min time window improved wear/nonwear classification accuracy when compared with the 60-min window. The Alg([Choi]) and Alg([Troiano]) performed better than the manufacturer-provided algorithm (Alg([ActiLife])), and the Alg([Choi]) performed better than the Alg([Troiano]) for wear/nonwear time classification using the data collected by both accelerometers.

CONCLUSIONS

Triaxial wrist-worn accelerometer can be used for an accurate wear/nonwear time classification in free-living older adults. The use of the 90-min window and the VM counts improves the performance of commonly used algorithms for wear/nonwear classification for both uniaxial and triaxial accelerometers.

Longitudinal associations between changes in physical activity and onset of type 2 diabetes in older British men: the influence of adiposity

OBJECTIVE

To determine how much physical activity (PA) is needed to protect against diabetes onset in older adults, whether protection is greater among overweight individuals, and whether taking up moderate activity in later life is beneficial.

RESEARCH DESIGN AND METHODS

Men (4,252) from a U.K. population-based cohort self-reported usual PA (regular walking and cycling, recreational activity, and sport) in 1996 and in 1998-2000, alongside other health behaviors and medical history. Fasting blood lipids were measured. Median follow-up was 7.1 years, during which 135 cases of type 2 diabetes (validated self-report) occurred.

RESULTS

Among 3,012 men free from cardiovascular disease and diabetes in 1998-2000, 9% reported no usual leisure-time PA, 23% occasional PA, and 15% vigorous PA. Compared with men reporting no activity, men reporting occasional, light, moderate, moderately vigorous, and vigorous PA had lower diabetes risks: hazard ratio (HR) 0.58 (95% CI 0.33-1.02), 0.39 (0.20-0.74), 0.38 (0.19-0.73), 0.39 (0.20-0.77), and 0.33 (0.16-0.70), respectively; P (trend) = 0.002, adjusted for age, social class, tobacco, alcohol, diet, and blood lipids. Adjustment for BMI, waist circumference, or fasting insulin attenuated HRs. HRs were stronger in men with BMI ≥28 vs. <28 kg/m(2) (interaction P = 0.02). Compared with men reporting light activity or less in 1996 and 2000, men who became at least moderately active by 2000 or remained at least moderately active at both times had adjusted HRs of 0.62 (0.34-1.12) and 0.51 (0.31-0.82), respectively.

CONCLUSIONS

Even light PA markedly reduced diabetes risk in older men, especially among the overweight or obese. Taking up or maintaining at least moderate PA in older adulthood strongly protected against diabetes.

Complementary medicine, exercise, meditation, diet, and lifestyle modification for anxiety disorders: a review of current evidence

Use of complementary medicines and therapies (CAM) and modification of lifestyle factors such as physical activity, exercise, and diet are being increasingly considered as potential therapeutic options for anxiety disorders. The objective of this metareview was to examine evidence across a broad range of CAM and lifestyle interventions in the treatment of anxiety disorders. In early 2012 we conducted a literature search of PubMed, Scopus, CINAHL, Web of Science, PsycInfo, and the Cochrane Library, for key studies, systematic reviews, and metaanalyses in the area. Our paper found that in respect to treatment of generalized anxiety or specific disorders, CAM evidence revealed current support for the herbal medicine Kava. One isolated study shows benefit for naturopathic medicine, whereas acupuncture, yoga, and Tai chi have tentative supportive evidence, which is hampered by overall poor methodology. The breadth of evidence does not support homeopathy for treating anxiety. Strong support exists for lifestyle modifications including adoption of moderate exercise and mindfulness meditation, whereas dietary improvement, avoidance of caffeine, alcohol, and nicotine offer encouraging preliminary data. In conclusion, certain lifestyle modifications and some CAMs may provide a beneficial role in the treatment of anxiety disorders.

Applying the ecological model of behavior change to a physical activity trial in retirement communities: description of the study protocol

OBJECTIVES

To describe the intervention protocol for the first multilevel ecological intervention for physical activity in retirement communities that addresses individual, interpersonal and community influences on behavior change.

DESIGN

A cluster randomized controlled trial design was employed with two study arms: a physical activity intervention and an attention control successful aging condition.

SETTING

Sixteen continuing care retirement communities in San Diego County.

PARTICIPANTS

Three hundred twenty older adults, aged 65 years and older, are being recruited to participate in the trial. In addition, peer leaders are being recruited to lead some study activities, especially to sustain the intervention after study activities ceased.

INTERVENTION

Participants in the physical activity trial receive individual, interpersonal and community intervention components. The individual level components include pedometers, goal setting and individual phone counseling. The interpersonal level components include group education sessions and peer-led activities. The community level components include resource audits and enumeration, tailored walking maps, and community improvement projects. The successful aging group receives individual and group attention about successful aging topics.

MEASUREMENTS

The main outcome is light to moderate physical activity, measured objectively by accelerometry. Other objective outcomes included physical functioning, blood pressure, physical fitness, and cognitive functioning. Self report measures include depressive symptoms and health related quality of life.

RESULTS

The intervention is being delivered successfully in the communities and compliance rates are high.

CONCLUSION

Ecological Models call for interventions that address multiple levels of the model. Previous studies have not included components at each level and retirement communities provide a model environment to demonstrate how to implement such an intervention.

Age effect on myocellular remodeling: response to exercise and nutrition in humans

Aging is associated with decline in muscle mass and muscle functions. Muscle strength declines disproportionate to the decline in muscle mass indicating that muscle quality or protein quality also declines with age. Human studies have shown a progressive decline in muscle protein synthesis including proteins in the contractile apparatus and mitochondria with age. However, the decline in muscle protein synthesis is disproportionate to the decline in muscle mass that occurs with age prompting to hypothesize that muscle protein degradation also declines with age. A decline in mitochondrial capacity to synthesize ATP is likely a limiting factor of both synthesis and degradation, which are ATP dependent processes. In support of the above hypothesis, several studies have shown a decline in whole body protein turnover (synthesis and degradation). The timely and efficient degradation of irreversibly damaged or modified proteins is critical to maintain the quality of protein. It is proposed that a failure to degrade the damaged proteins and replacing them with newly synthesized proteins contribute to age related decline in muscle mass and quality of muscle proteins. The underlying molecular mechanism of these age related changes in human muscle needs further investigation.