Confirming a beneficial effect of the six-minute walk test on exercise confidence in patients with heart failure

Background:

Low confidence to exercise is a barrier to engaging in exercise in heart failure patients. Participating in low to moderate intensity exercise, such as the six-minute walk test, may increase exercise confidence.

Aim:

To compare the effects of a six-minute walk test with an educational control condition on exercise confidence in heart failure patients.

Methods:

This was a prospective, quasi-experimental design whereby consecutive adult patients attending an out-patient heart failure clinic completed the Exercise Confidence Scale prior to and following involvement in the six-minute walk test or an educational control condition.

Results:

Using a matched pairs, mixed model design ( n=60; 87% male; Mage=58.87±13.16), we identified a significantly greater improvement in Total exercise confidence ( F(1,54)=4.63, p=0.036, partial η2=0.079) and Running confidence ( F(1,57)=4.21, p=0. 045, partial η2=0.069) following the six-minute walk test compared to the educational control condition. These benefits were also observed after adjustment for age, gender, functional class and depression.

Conclusion:

Heart failure patients who completed a six-minute walk test reported greater improvement in exercise confidence than those who read an educational booklet for 10 min. The findings suggest that the six-minute walk test may be used as a clinical tool to improve exercise confidence. Future research should test these results under randomized conditions and examine whether improvements in exercise confidence translate to greater engagement in exercise behavior.

The Response of Wheat to High Temperature Following Anthesis. I. The Rate and Duration of Kernel Filling

Wheat (Triticum aestivum L.) plants were grown to anthesis at 18/13�C day/night and either retained at 18/13�C or transferred to a higher temperature (24/19 or 30/25�C) for the grain-filling period. It was confirmed that high temperature resulted in a considerable drop in kernel dry weight at maturity and there was significant cultivar variation in the degree of the response. ranging from a 30 to 60% decrease in kernel dry weight at maturity for a rise in temperature from 18/13 to 30/25�C. An analysis of the rate and duration of kernel filling of seven cultivars showed that those cultivars most tolerant of high temperature during kernel filling (least reduction of kernel dry weight at maturity) were those where the rate of kernel filling was most enhanced by high temperature, i.e. the increased rate compensated for the reduced duration of kernel filling. The importance of the rate of kernel filling in determining varietal responses to high temperature illustrates the need to isolate the effect of temperature on processes in the kernel during the linear phase of growth.

Source, sink and hormonal control of translocation in wheat

An analysis of the pattern of movement of (14)C-labelled flag leaf assimilates in wheat (Triticum aestivum l. c.v. Gabo) during grain development, indicated that the greater the requirement for assimilates by the ear the more rapid was the speed of movement of these through the peduncle to the ear and also the lower their concentration. Experiments with [(14)C] indoleacetic acid ([(14)C]IAA) suggested that auxin production by the grains was not responsible for the control of assimilate translocation through the peduncle. Limiting the supply of available assimilates by shading the lower parts of the plant, did not significantly alter the speed of movement of (14)C-photosynthate through the peduncle, while severing half of the vascular tissue in the peduncle altered the pattern of movement of (14)C to the ear and enhanced the speed of movement of (14)C through the remaining functional conducting tissue. These results are discussed in relation to the mechanism of translocation.