Energy expenditure and heart rate response to breaking up sedentary time with three different physical activity interventions

BACKGROUND AND AIMS

Prolonged sedentary behaviour is associated with increased cardiovascular disease risk and decreased energy expenditure (EE). Workplace interventions breaking up sedentary time have increased EE but the cardiovascular responses are unknown. The practicalities of these interventions, such as required costs and workplace adaptations, are questioned. Calisthenics exercises overcome such limitations, but have not been assessed. The aim of this study was to assess the EE and heart rate (HR) response when breaking up sedentary time with a short bout of standing, walking or calisthenics.

METHODS AND RESULTS

Twenty healthy participants (15 male) completed four 30 min conditions: a) 30 min sitting, or breaking up this period with two minutes of b) standing, c) treadmill walking (4 km·h(-1)) or d) a set of calisthenics exercises (including squats and lunges). HR and EE (indirect calorimetry) were assessed throughout. During the activity break, calisthenics caused the highest HR (90 ± 12 bpm) compared to all other conditions (Sit: 70 ± 12 bpm; Stand:72 ± 13 bpm; Walk:84 ± 10 bpm; p < 0.001) and EE was the highest with calisthenics (13 ± 5 kcal) compared to all conditions except walking (Sit:3 ± 1 kcal; Stand:5 ± 1 kcal; p < 0.001). The recovery following calisthenics had highest total EE (27 ± 7 kcal) compared to walking (23 ± 6 kcal) and standing (22 ± 6 kcal) and also the longest elevation of HR (p < 0.001).

CONCLUSION

Calisthenics led to a greater total EE and HR response compared to standing or walking interventions. Calisthenics may be a time efficient method to break up sedentary time without individuals leaving their work environment. Hence calisthenics could be utilised to disrupt workplace sedentary time and improve cardiovascular health and assist in weight management.

Molecular typing of the etiologic agent of human granulocytic ehrlichiosis

The p44 gene of the agent of human granulocytic ehrlichiosis (aoHGE) encodes a 44-kDa major outer surface protein. A technique was developed for the typing of the aoHGE based on the PCR amplification of the p44 gene followed by a multiple restriction digest with HindIII, EcoRV, and AspI to generate restriction fragment length polymorphism patterns. Twenty-four samples of the aoHGE were collected from geographically dispersed sites in the United States and included isolates from humans, equines, canines, small mammals, and ticks. Six granulocytic ehrlichiosis (GE) types were identified. The GE typing method is relatively simple to perform, is reproducible, and is able to differentiate among the various isolates of granulocytic ehrlichiae in the United States. These characteristics suggest that this GE typing method may be an important epizootiological and epidemiological tool.

Isolation of the etiologic agent of human granulocytic ehrlichiosis from the white-footed mouse (Peromyscus leucopus)

We examined white-footed mice (Peromyscus leucopus) from Minnesota for infection with the etiologic agent of human granulocytic ehrlichiosis (HGE). From April to September 1997, we collected P. leucopus from Washington County, Minnesota, an area enzootic for HGE. Blood was cultivated in HL60 cells for isolation of the HGE agent. Of 59 mice examined, only a single mouse was culture positive for the HGE agent. The 16S ribosomal DNA sequence of the isolate was determined to be identical to that of the HGE agent. The isolate was reactive with monoclonal antibodies to the 44-kDa antigen of the HGE agent and was infectious for laboratory mice.

Accidents in older people living at home: a community-based study assessing prevalence, type, location and injuries

OBJECTIVES

To assess the prevalence, type, location of and injuries from home accidents, including falls and other accidents, and to explore whether variables including socio-demographic characteristics, medication use and home hazards were associated with all home accidents and falls.

METHOD

657 older people were interviewed about accidents in the previous four weeks. For a subsample (n = 425), a home hazard check was completed.

RESULTS

Of the 101 accidents reported, 51% (n = 51) were falls and 50% (n = 50) were other accidents. The most common location for all accidents was outside (30%). Most resulted in minor injury to the legs (43%) or arms (39%). Medical treatment was sought for 14% of accidents. Having more than five hazards and infrequent home visits by healthcare providers were associated with having at least one accident and at least one fall. Use of a walking aid was also associated with falling.

CONCLUSION

Rates of falls and other accidents are considerable.

IMPLICATIONS

Work is required to confirm the importance of the relationships suggested and to provide data on the burden of injury associated with non-fall accidents.

SAW device implementation of a weighted stepped chirp code signal for direct sequence spread spectrum communications systems

This paper introduces a new weighted stepped chirp code signal for direct sequence spread spectrum (DS/SS) communications systems. This code signal uses the truncated cosine series functions as the chip functions, and it is the result of discretizing a continuous wave (CW) chirp that results in enhanced performance versus a pseudonoise (PN) code and equivalent performance and easier implementation than a CW chirp. This code signal will be shown to have improved compression ratio (CR) and peak sidelobe level (PSL) versus a PN code with identical code length and chip length. It also will be shown to have a similar CR and PSL compared to a CW chirp with identical pulse length and frequency deviation. The code signal is implemented on surface acoustic wave (SAW) devices that will be used as the code generator at the transmitter and the correlator at the receiver. The design considerations for the SAW device implementation of the code signal are discussed, including the effects of intersymbol interference. Experimental data is presented and compared to the predicted results for 8 different SAW devices examining the effects of code length (9 or 13 chips), weighting (uniform, cosine-squared, and Hamming), and sampling on the performance of the code signal.

Environmental hazards in the homes of older people

OBJECTIVES

To investigate (i) the prevalence of environmental safety hazards in the homes of people aged 70 years and over, (ii) their knowledge of causes of injuries to older people and the safety measures they can implement to prevent such injuries and (iii) the relationship between socio-demographic characteristics of this population group and levels of home environmental hazards.

METHOD

A cross-sectional survey of 425 people aged 70 years and older living in a defined geographical area of Australia. Participants were recruited through their general practitioners. A structured interview completed with each participant included questions on demographics and home safety issues. A home safety inspection was also undertaken using a predetermined rating format.

RESULTS

80% (n = 342) of homes inspected had at least one hazard and 39% (n = 164) had > 5 hazards. The bathroom was identified as the most hazardous room, with 66% (n = 279) of bathrooms having at least one hazard. Hazards relating to floor surfaces (62% of homes had one 'flooring' hazard) and absence of appropriate grab or handrails (60% of homes had one or more hazards relating to this) were prevalent. Eighty-eight percent (n = 374) of older people were able to identify falls as the most common cause of injury and 87% (n = 368) were able to accurately name at least one safety measure. Although a significant association was found between the older people's self-assessment of their home's safety and the presence of more than 5 hazards, 30% of those rating their homes as very safe (n = 289) had more than 5 hazards. Logistic regression analysis identified one variable--contact with healthcare service providers--as predictive of the hazard level in older people's homes. Older people who were never visited by service providers were twice as likely to have more than 5 hazards as those who were visited weekly or more often (OR 2.12, 95% CI 1.104, 4.088).

CONCLUSION

Many older people are living in potentially hazardous environments. As yet, a causal link between the presence of environmental hazards and falls in older people has not been established. More definitive work in this area needs to be carried out.

Finite impulse response utilizing the principle of superposition

A critical parameter in any finite impulse response (FIR) design is the impulse response length, which must be optimized for the given design specifications in order to reduce the size of the filter. To this end, many design algorithms have been introduced, such as Remez exchange, linear programming, and least mean squares. A new algorithm has been derived that is simple, efficient, and accurate for the design of arbitrary filter specifications and requires fewer computations than many other FIR approaches. This paper provides the definition of the basic functions used for the design process. An overview of the design process is given and the design technique used to design filters with tailored passband and stopband responses to yield a near-optimum time length is presented. This design can be very useful when compensating for the effects of a second transducer or other second order effects in surface acoustic wave (SAW) devices. The effects of monotonically increasing sidelobes on the impulse response length are discussed and illustrated. The addition of arbitrary phase response to the filter design process is discussed. The results of the current FIR approach are discussed and compared with other design techniques.

Radiolabeled fiber: a physiologic marker for gastric emptying and intestinal transit of solids

We report here a study of radiolabeled cellulose as a marker for gastric emptying and intestinal transit of fiber in a dog model. A chemically stable radioisotopic label (131I) was employed to facilitate external monitoring of the tracer. 131I-labeled fiber was found to be biologically stable, since no iodine was absorbed during passage through the canine digestive system. In comparison with water-soluble tracers, gastric emptying of [131I]fiber is very slow. This is consistent with the expected behavior of fiber as a nondigestible solid. We anticipate this new radiolabeled marker will prove to be a useful tool for studies on gastric emptying, intestinal transit, fate and actions of dietary fiber in nonruminant experimental animals and, eventually, in man.