Title: A preliminary investigation into the effect of continuous vigorous exercise and lifestyleembedded ph
1A preliminary investigation into the effect of
continuous vigorous exercise and
lifestyle-embedded physical activity upon acute
glycaemic regulation
Ash Routen1, Ann Rowlands2 Dale
Esliger2 1Institute of Sport Exercise Science,
University of Worcester, UK. 2School of Sport and
Health Sciences, University of Exeter, UK.
2Introduction
- Consensus that physical activity/exercise reduces
the risk of developing insulin resistance,
glucose intolerance and overt type 2 Diabetes
(Bassuk et al., 2005, Healy et al., 2006). - Majority of research is of a experimental design
with long term follow-up, detailing chronic
adaptations to exercise in diabetics. - Continuous glucose monitoring (CGM) has emerged
as a new tool for diabetics help maintain
normoglycaemia. CGM provides acute information
on ambulatory, postprandial and/or nocturnal
glucose excursions (Hay et al., 2003). - To date only two studies implementing CGM within
exercise protocols, charting acute glucose
responses to exercise may allow optimal
intervention (Klonoff, 2005).
3Aim
- Two concurrent aims-
- To determine the effect of continuous exercise
and lifestyle-embedded (intermittent bouts)
physical activity (as measured by accelerometry)
on the regulation of interstitial glucose (as
measured by CGM). - To determine the feasibility of CGM data
collection alongside exercise protocols.
4Methods
- One physically active non-diabetic male age 22
y mass 71.5 kg height 181 cm. - 8 days CGM (iPro, Medtronic, Northridge, USA) and
accelerometry data collection (Actigraph GT1Ms,
Actigraph USA). - 3 trial conditions
- Sedentary control (lt 2500 steps, pedometer
controlled). - Continuous exercise condition (2 x 30 min
treadmill running at 70 HRmax). - lifestyle-embedded physical activity condition
(100 min of physical activity including stair
climbing, brisk walking outside etc.).
5Table 1. Experimental Design
6Figure 1. Medtronic MiniMed (SOF-SENSOR) glucose
sensor
Figure 1.1. CGMS iPro digital recorder attached
to SOF-SENSOR
7Results
8Results continued
9Results continued
- The relationship between physical activity counts
(as measured by accelerometry) and glucose values
was assessed during various parameters (e.g.
exercise, postprandial) via Pearson's correlation
analysis. The alpha level was set at lt0.05. - A strong positive correlation was identified
during the continuous exercise bouts (R 0.75, P
0.02).
10Discussion
- Tighter glycaemic control potentially due to
elevated glucose uptake resulting from increased
GLUT-4 translocation to cellular membrane
(Kennedy et al., 1999 Sigal et al., 2004). - Greater uptake in continuous vs. lifestyle
condition as muscle glucose uptake is greater at
higher intensities - increased GLUT-4, blood flow
etc. (Romijn et al., 1993). - Positive correlation during continuous bouts may
be due to increased hepatic glucose production
(Wasserman et al., 1996). - However 5 min time delay between interstitial
glucose and blood glucose , so time lag
correlations may prove more accurate (Klonoff,
2005).
11Conclusion/Future Research
- Day to day glucose regulation in a normoglycaemic
individual may be achieved through undertaking
vigorous intensity aerobic exercise. - Lifestyle physical activity (of the same energy
expenditure), a suitable alternative for
unwilling and unable. - CGM data collection is feasible.
- Limited by single participant design and
normoglycaemic population. - Future studies should increase sample size and
include pre-diabetic and overt diabetic
populations.
12References
- Bassuk, S. S., Manson, J. E. (2005).
Epidemiological evidence for the role of physical
activity in reducing risk of type 2 diabetes and
cardiovascular disease. J Appl Physiol, 99(3),
1193-1204. - Hay, L. C., Wilmshurst, E. G., Fulcher, G.
(2003). Unrecognized hypo- and hyperglycemia in
well-controlled patients with type 2 diabetes
mellitus the results of continuous glucose
monitoring. Diabetes Technol Ther, 5(1), 19-26. - Healy, G. N., Dunstan, D. W., Shaw, J. E.,
Zimmet, P. Z., Owen, N. (2006). Beneficial
associations of physical activity with 2-h but
not fasting blood glucose in Australian adults
the AusDiab study. Diabetes Care, 29(12),
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subjects and subjects with type 2 diabetes.
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13 Klonoff, D. C. (2005). A review of continuous
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