Acute effects of different intensities of exercise in normoalbuminuric/normotensive patients with type 1 diabetes.

OBJECTIVE: The purpose of this study was to investigate the effect of exercise occurrence and intensity on albumin excretion in normotensive, normoalbuminuric patients with type 1 diabetes. RESEARCH DESIGN AND METHODS: Eighteen patients (aged 29 +/- 2 years, duration of diabetes 14 +/- 2 years, blood pressure 120 +/- 2/74 +/- 1 mmHg, HbA(1c) 7.0 +/- 0.2% [mean +/- SE]) without microalbuminuria, hypertension, or anti-angiotensin II therapy participated in two exercise studies in a clinical research center. Exercise intensities were defined as moderate (50% heart rate reserve [HRR]) and intense (75% HRR) and were performed in random order. Subjects collected urine for albumin determination on the days before and after exercise. On the day of exercise, subjects exercised for 30 min on a treadmill at the assigned intensity. Timed urine collections were obtained over the day. Blood pressures were measured using an ambulatory blood pressure monitor. RESULTS: Moderate exercise demonstrated no changes in albumin excretion. Intense exercise demonstrated a significant increase in albumin excretion during the first 4 h compared with the rest of the day (P = 0.03) but returned to normal thereafter. Albumin excretion did not exceed normal levels throughout the study. There was no difference in albumin excretion surrounding days of intense exercise. Ambulatory blood pressures demonstrated nocturnal dipping after moderate and intense exercise (P < 0.001). CONCLUSIONS: We have demonstrated that normotensive, normoalbuminuric patients without anti-angiotensin II therapy do not have elevated albumin excretion following exercise intensities experienced by most patients with type 1 diabetes.