Date of Award

Spring 2012

Document Type


Degree Name

Doctor of Philosophy (PhD)


Human Movement Sciences


Human Movement Sciences

Committee Director

Sheri R. Colberg-Ochs

Committee Director

Aaron Vinik

Committee Member

C. Thomas Somma


The rise in prevalence and incidence of type 2 diabetes mellitus (T2D) in the developing world continues unabated. Current treatment strategies, however, fall short of achieving optimal glycemic control. The aim of project I was to investigate the effect of an acute bout of a yogic breathing exercise on heart rate variability (HRV) in individuals with T2D. Project II was designed to assess the effectiveness of the neurohormone melatonin in lowering short- and long-term glucose levels, lipids and oxidative stress in T2D. Project III investigated the differential effects of two different styles of aerobic exercise on postprandial glycemia, mood and HRV in T2D.

Project I investigated the effect of short-term breathing exercises and demonstrated significant differences between the T2D group and an age-matched normoglycemic group (CON) in resting measures of HRV. Standard deviation of consecutive heart beats (SDNN), the square root of the mean squared differences (RMSSD) and total spectral power (TP) were almost uniformly lower in the T2D group than the CON group. A within-group analysis revealed no significant effect of breathing exercise upon HRV in the CON group. However, a 10-minute breathing protocol involving selective breathing through only the left nostril demonstrated a significant reduction in resting heart rate in the T2D group (-1.2 beats per minute, or bpm) compared to the heart rate average during the entire breathing protocol, indicating a possible acute improvement in vagal tone.

Project II, which investigated the effect of six weeks of melatonin supplementation on short-and long-term glycemic control, lipids, and oxidative stress in T2D, yielded impressive results. There was a significant reduction in malondialdehyde, a marker of oxidative stress (-6.3 vs. 0.7nmol/ml), as well as a significant drop in glycated hemoglobin (-0.24%±0.23) in the melatonin group vs. the placebo group.

Project III examined the impact of a more recreational style of exercise (table tennis) following a dinner meal vs. a more traditional exercise (walking). Our results indicated that self-paced walking generated a significantly higher heart rate than table tennis, which translated into a significant drop in blood glucose levels following a 30-minute bout of exercise. We did not, however, note any difference in mood between the two groups.


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