Relationship of changes in maximal and submaximal aerobic fitness to changes in cardiovascular disease and non-insulin-dependent diabetes mellitus risk factors with endurance training: The Heritage Family Study

The purpose of this study was to determine the relationship between changes in maximal oxygen uptake (VO2 max) and submaximal markers of aerobic fitne ss and changes in risk factors for cardiovascular disease (CVD) and non-ins ulin-dependent diabetes mellitus (NIDDM) consequent to a 20-week endurance training program. The 502 participants in this study were healthy and previ ously sedentary men (n = 250) and women (n = 252) of varying age (17 to 65 years) and race (blacks n = 142; whites n = 360) who had completed the HERI TAGE Family Study testing and training protocol. Following baseline measure ments, participants trained on cycle ergometers 3 days/week for a total of 60 exercise sessions starting at the heart rate (HR) associated with 55% of VO2 max for 30 minutes/session. This was progressively increased to the HR associated with 75% of VO2. max for 50 minutes/session, which was maintain ed during the last 6 weeks. VO2 max, heart rate at 50 W, power output at 60 % of VO2 max, lipids and lipoproteins, resting blood pressure, body composi tion including abdominal fat (computed tomography [CT] scan), and blood glu cose and insulin at rest and at peak following an intravenous glucose toler ance test (IVGTT) were determined both before and after training. Following training, there were significant increases in VO2 max (16%) and the power output at 60% of VO2 max and a significant decrease in HR at 50 W. These ch anges in markers of aerobic fitness were significantly correlated only to t he changes in the body composition variables and the lipids and lipoprotein s. Further, there was considerable individual variation in response for all variables studied. Finally, when risk factor data were analyzed by quartil e of change in VO2 max, there were few significant relationships. It is con cluded that there is a significant relationship between changes in markers of aerobic fitness and changes in several risk factors for CVD and NIDDM. H owever, the magnitude of these relationships is small. Copyright (C) 2001 b y W.B. Saunders Company.