Cardiorespiratory Responses to Cycling Exercise in Trained and Untrained Healthy Elderly: With Special Reference to the Lactate Threshold

Abstract

The fastest growing age group in the United States and Japan is the elderly. There is a need to develop appropriate exercise training guidelines designed specifically for healthy older persons. Recent reports have shown that the lactate threshold (LT) can be used to evaluate the clinical significance of aerobic power (VO₂max) and its effect of exercise training in the elderly. However, there is a lack of research comparing the LT between well-trained and sedentary elderly individuals. Also, the effect of exercise training on the heart rate (HR) at LT needs further investigation. The purpose of this study was to compare the LT levels between the older trained men (T group; n=72, age=71.3 ± 5.8 yr, range 60-85 yr) and apparently healthy but untrained elderly men (U group; n=172, age=72.2 ± 5.7 yr, range 60-93 yr). The LT was measured during an incremental cycle ergometer test. A low relationship was found between VO₂ corresponding to LT (VO_2LT) and age in the T (r=0.20, P<0.05) and U groups (r=0.43, P<0.05). A significant difference was found in the VO_2LT between the T and U groups. The absolute VO_2LT corresponded to approximately 6 and 4 METs for the T and U subjects, respectively. However, there was no significant difference in HR corresponding to LT (HR_LT) between the two groups (T; 109 ± 19 b·min^-1, U; 107 ± 13 b·min^-1). The data show that the absolute VO_2LT is higher for T than U elderly subjects and is associated with a HR of approximately 108 b·min^-1 for both groups. Recommended exercise intensity in terms of HR may not differ between trained and untrained elderly men.