A preliminary investigation into the effect of continuous vigorous exercise and lifestyleembedded ph

1
A 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.
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Introduction

• 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).

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Aim

• 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.

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Methods

• 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.).

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Table 1. Experimental Design
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Figure 1. Medtronic MiniMed (SOF-SENSOR) glucose
sensor
Figure 1.1. CGMS iPro digital recorder attached
to SOF-SENSOR
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Results
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Results continued
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Results 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).

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Discussion

• 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).

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Conclusion/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.

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References

• 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),
  2598-2604.
• Kennedy, J. W., Hirshman, M. F., Gervino, E. V.,
  Ocel, J. V., Forse, R. A., Hoenig, S. J., et al.
  (1999). Acute exercise induces GLUT4
  translocation in skeletal muscle of normal human
  subjects and subjects with type 2 diabetes.
  Diabetes, 48(5), 1192-1197.

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Klonoff, D. C. (2005). A review of continuous
glucose monitoring technology. Diabetes Technol
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