The influence of glycosylated hemoglobin on oxygen consumption in women

Donna Marie Barrett, Purdue University

Abstract

Type 2 diabetes is one of the most frequently encountered chronic diseases in the world. It is estimated to affect over 12 million adults in the United States, half of whom are women. Exercise is one of three strategies recommended for the treatment of type 2 diabetes despite its limited effectiveness in promoting glycemic control. Research has consistently shown that individuals with type 2 diabetes experience impaired aerobic abilities compared to healthy counterparts for reasons that are yet unknown. The purpose of this study was to examine the influence of glycosylated hemoglobin (HbA1c) on oxygen consumption (VO2max) and to explore the role of 2,3 BPG in this relationship. Ten middle-aged normoglycemic (HbA1c, 3.0–5.5%) and nine hyperglycemic women (HbA1c, 3.0–10%) exercised aerobically with personal trainers for 15 weeks, 3 times a week at 50–85% VO 2max for 30 to 45 minutes. Seven women served as controls. Body composition, hemoglobin, hematocrit, HbA1c, 2,3 BPG and VO2max were measured prior to and following the intervention. ANOVAs, repeated measures ANOVAs, ANCOVAs and correlations were used to determine differences between and within groups, and associations between HbA1c, VO2max and 2,3 BPG. Significant differences (p < .05) were found between the intervention groups in VO2max at baseline (22.8 versus 19.3 ml/kg/min) and posttest (24.6 versus 21.0 ml/kg/min), with normoglycemic women experiencing a 15% higher VO2max than hyperglycemic women. Nevertheless, hyperglycemic women improved as much as normoglycemic women in both HbA 1c (4% vs. 3%) and in VO2max (9% vs. 8%) following exercise training. HbA1c and VO2max were significantly inversely correlated at baseline (r = −.55) and at posttest (r = −.38). There were no significant differences in 2,3 BPG between groups, nor any significant correlations between 2,3 BPG, HbA1c and VO2max at either baseline or posttest. This study suggests that women with type 2 diabetes can improve metabolic control and aerobic ability as much as normoglycemic women with 15 weeks of moderate-intensity, supervised, and supported exercise training despite their lower initial oxygen consumption values.

Degree

Ph.D.

Advisors

Lyle, Purdue University.

Subject Area

Physical therapy|Biochemistry|Kinesiology|Therapy

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