Age-associated blood glucose levels during exercise in female swimmers.

The purpose of this study was to determine whether age-associated alterations in blood glucose levels occur during exercise. In addition, blood lactate and fitness levels (VO2max) were examined to ascertain if these factors influenced the age-related responses. Sixty-four female masters swimmers (25-75 years) were classified into either a well trained (WT) or recreational trained (RT) group and exercised on a treadmill to VO2max X VO2max data confirmed our classification of WT and RT swimmers based on activity levels. There were no differences in post-absorptive blood glucose and lactate levels across age and fitness. Significant age-related effects on blood glucose levels during exercise (p less than 0.01) but no fitness effect were revealed by ANOVA. Within the first or second exercise stage all age groups demonstrated a significant decline in blood glucose (6.3 to 14.1%). A hyperglycemic response was observed during recovery in all age groups with the exception of the over 60 (60+) group. The 60+ group exhibited lower blood glucose levels compared to all other age groups during exercise commencing with the second exercise stage. There were no significant differences in glucose levels among any of the other age groups during exercise or recovery. There were no age-related differences in maximal or recovery lactates. These data indicate that there is an alteration of blood glucose homeostasis during exercise in females over 60 years of age.