The influence of walking on risk factors associated with metabolic syndrome

Scott, A. (2008) The influence of walking on risk factors associated with metabolic syndrome. Ph.D. thesis, University of Kent.

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Abstract

Metabolic syndrome (MetS) represents a cluster of metabolic abnormalities, characterised
by the presence of 3 or more of 1) abdominal obesity, 2) insulin resistance, 3)
hypertension, 4) dyslipidaemia, and 5) emerging risk factors, such as pro-thrombotic and
pro-inflammatory states, which are each independent cardiovascular disease (CVD) risk
factors. This clustering of risk factors is reported to increase the odds ratio for
cardiovascular and all-cause mortality above the risk associated with the individual
components (Wilson, 2004). The precise aetiology of MetS is currently unknown, however
an energy-dense diet, particularly high in carbohydrate, and an inactive lifestyle or low
fitness may interact with a genetic susceptibility to contribute to the pathophysiology of
MetS (Bouchard, 2007). Therefore the purpose of the studies included in this thesis were to
determine whether accumulative brisk walking may improve risk factors associated with
MetS and whether one single session of brisk walking at a moderate intensity may improve
risk factors associated with MetS in middle-aged men at risk of MetS. Study one recruited
85 males aged 38-73 onto a 24-week randomised controlled trial with participants allocated
to control (CON), single 30 minute daily brisk walking (SBW) or accumulative 30 minutes
of daily brisk walking (ABW; 3×10 min or 2×15 min) groups. Measures included aerobic
fitness (OO2max), body composition and selected blood variables. The main findings were
that 24 weeks of accumulating 150 min·wk-1 of brisk walking at ~65% HRmax significantly
improved insulin sensitivity, which was associated with decreased abdominal adiposity,
assessed by waist circumference, and was at least as effective as a single daily session of
equal volume in middle-aged men at risk of MetS. Study two investigated the 24-hour
effect of walking for 30 minutes at 50% OO2max (30×50%), 30 minutes at 65% OO2max
(30×65%) and 60 minutes at 50% OO2max (60×50%) compared to rest (CON) on
cardiovascular control, resting metabolism and selected blood variables. The main findings
were that a single 30 minute walking session at 50% OO2max favourably improved
cardiovascular control, indicated by decreased heart rate and systolic blood pressure, thus
decreasing the workload of the heart, whereas increasing the intensity of the walk to 65%
OO2max attenuated this effect, while increasing the duration to 60 minutes had no additional
effect compared to 30 minutes at 50% OO2max in men at risk of MetS.

Item Type: Thesis (Doctoral)
Subjects: R Medicine > RC Internal medicine > RC0581 Specialties of internal medicine > RC0627 Metabolic diseases
Depositing User: Mr Andrew Hudson
Date Deposited: 23 Jul 2013 12:41
Last Modified: 17 Dec 2017 05:20
URI: https://create.canterbury.ac.uk/id/eprint/12120

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Last edited: 29/06/2016 12:23:00